Fatigue of E-glass fiber reinforced composite materials and substructures by Daniel David Samborsky A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering Montana State University © Copyright by Daniel David Samborsky (1999) Abstract: Fiberglass composites have been used in thousands of applications since their inception in the late 1930's despite an incomplete understanding and characterization of their mechanical fatigue properties. Wind turbine blades, which are the main focus of this research, experience between10^8 to10^9 significant fatigue (loading-unloading) cycles in their 20 to 30 year lifetime, and fatigue is a major factor in their design. This thesis presents a detailed analysis of the DOE/MSU Composite Material Fatigue Database, which has been developed over the last nine years. The database currently includes over 6000 static and fatigue test results covering 148 different fiberglass materials and numerous loading conditions. Trends in fatigue resistance with various materials and loading parameters are explored, including: reinforcement fabric architecture, fiber content, content of fibers orientated in the load direction, matrix material and loading conditions (tension, compression and reversed loading). The results show unexpected transitions in fatigue resistance with fiber content and fabric architecture. Transitions to increased fatigue sensitivity have been related to fiber packing characteristics through detailed microscopy study. Material characteristics which produce maximum fatigue resistance have been established. Very high cycle tensile fatigue behavior (10^9 cycles) has been explored with a novel high frequency apparatus using impregnated strands. The strand data suggest a reduction in fatigue sensitivity in the 10^8 to 10^9 cycle range, but a material endurance limit has not been seen. Larger impregnated glass strands tested in excess of 10^8 cycles using conventional testing equipment provide similar results to the smaller strands. The study has also explored the application of the database to the prediction of the fatigue response of small composite substructures representative of wind turbine blades. Thirty six I-beams were tested under four-point bending. The beams were constructed of materials which showed a range of fatigue resistance in the materials coupon tests. The coupon database accurately predicted the performance of the beams when the failure modes were predominately tensile or compressive. Delamination of the tensile flange in the beams with improved fatigue resistance materials, due to the increase in bending loads and flange operating strains, provided less conclusive results. The effect of flaws (through-thickness holes) was also explored. A second geometry, hollow tubes, was also explored in conjunction with field tests on a small wind turbine. Twenty seven hollow tube test sections were tested under four-point and cantilever bending. Due to the hollow tube geometry, the compressive buckling behavior was the limiting static design parameter, and the obtained compressive strains in the tubes were slightly lower than the database compressive strength values (which used very short specimens).  FATIGUE OF E - GLASS FIBER REINFORCED COMPOSITE MATERIALS AND SUBSTRUCTURES by Daniel David Samborsky A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Civil Engineering MONTANA STATE UNIVERSITY Bozeman,. Montana December 1999 © COPYRIGHT by Daniel David Samborsky 1999 All Rights Reserved APPROVAL of a thesis submitted by Daniel David Samborsky This thesis has been read by each member of the thesis committee and has been found to be satisfactory regarding content, English usage, format, citations, bibliographic style, and consistency, and is ready for submission to the College of Graduate Studies. Dr. John F. Mandell irperson, Graduate Committee Approved for the Department of Civil Engineering Dr. Don Rabern D Head, Civil Engineering Department Date Approved for the College of Graduate Studies / 6 ^ Dr. Bruce McLeod Graduate Dean Date STATEMENT OF PERMISSION TO USE In presenting this thesis in partial fulfillment of the requirements for a master's degree at Montana State University, I agree that the Library shall make it available to borrowers under rules of the Library. I have indicated my intention to copyright this thesis by including a copyright notice page, copying is allowable only for scholarly purposes, consistent with "fair use" prescribed in the U.S. Copyright Law. Requests for permission for extended quotation from or reproduction of this thesis in whole or in parts may be granted only by the copyright holder. Signature Date iv I have been both a student and a research engineer at MSU for over 10 years and this thesis is a collection of some of the research I have performed. I estimate 63,000 machine hours and over 16,000 personal hours are present in this document, and as no good deed goes unpunished, and I have made many personal sacrifices in performing this research, but it has been my choice, as it was the only way to get it done and to accomplish something that needed to be done. This is by no means an average masters thesis, and both the amount, and detail of research can only be attributed to the truly outstanding mentors, and friends, I work with, notably: Dr. John Mandell (composites), Dr. Jerry Stephens (engineering) and Dr. Doug Cairns (composites). No one can achieve work like this without exceptional parents and family, like my father James Samborsky, P. Eng. (B.S., M.S. civil, B.S. mechanical engineering (all MSU)), mother Judith; brothers Richard (B.Ed.) and Scott, and a special sister Tanya. I wish that my mother and Scott were alive to celebrate this achievement with me. I want to also mention a special friend, who, unfortunately, at the time, did not understand my engineering passion, Teresa Keef, and my other friends and co-workers, who, at the time, did not understand the humor or t-shirts, which were (actually) funny. This work was supported by the following: Sandia National Laboratories, subcontracts 40-8875, 18-3958, AN-0412 and BC7159; the National Renewable Energy Laboratory, subcontracts XE-1-11009-5 and XAF-5-14076-04; and the Department of Energy through the DOE EPSCoR Program, contract DE-FC02-91ER75681. ACKNOWLEDGMENTS TABLE OF CONTENTS LIST OF TABLES..........................................................................................................viii LIST OF FIGURES ........................................................................................................ x ABSTRACT...................................................................................................... xxiv 1. INTRODUCTION......................................................................................................... I 2. FABRICATION OF MATERIALS............................................................................... I Fabric Reinforcement............................................. 7 Resins..................................................................................................................... 9 Flat Rectangular Plate Construction ....................................................................12 E - Glass Prepreg................................................................................................. 14 Industrial Supplied Materials ................................................................................15 Machining ......... 15 Test Specimen Geometries ................................................................................. 16 I - Beam Construction ......................................................................................... 20 Cylindrical Tubes................................................................................................. 24 Fiber Volume Fraction (Vf) Determination......................................................... 25 3. MECHANICAL TESTING EQUIPMENT................................................................. 29 Load Cells ........................................................................................................... 29 Extensometers ..................................................................................................... 31 Actuator Position (LVDT)................................................................................... 32 Strain Gages......................................................................................................... 33 Testing Machine Load Train Alignment........................................................ . .35 Fiber Testing Apparatus........ ...............................................................................37 4. TESTING AND TEST DEVELOPMENT ................................................................. 40 Coupon T ests..................................................................... 40 Tensile Tests .......................................................................................................41 Tensile T est Development............................ ....... ■............................................ 45 Test Coupon Gripping............................................................................! ......... 48 Compressive Test Development ....................*................................................. 54 I - Beam 4 Point Bending Development ............... 59 Cylindrical Tube Bending Tests............................................................ '. ........... 62 5. COUPON TESTS ......................................................... 63 Unidirectional Materials ..................................................................................... 63 Fiber Packing........................................................................................... 63 Strand Deformations in Fabrics............................................................... 64 Unidirectional fatigue behavior............................................................... 76 Background ........................ 76 Results and Discussion ............................................................... 78 Variability in Properties of Strands Taken From Fabric ............. 79 Unidirectional Laminates..................................................................................... 87 ±45° Fabrics....................................................................................................... 101 Materials With Varying Amounts of ±45° and 0° Plies ....................................107 Fatigue Trends................................................................................... 108 Effect of R Value................................................................................................120 Comparison of Materials................................................................................... 120 Failure Modes ....................................................................................... 130 Fabric Architecture Effects ....................................................................138 Conclusions ....................................... 144 6. BALANCED ANGLE PLY LAMINATES................................................... 146 Background Information ................................................................................... 146 Testing Methods................................................................................................. 150 Results and Discussion ..................................................................................... 152 Laminate Analysis Predicted Properties ........................................................... 158 Fatigue Testing...................................................................................... '...........165 Failure modes..................................................................................................... 174 Conclusions for Balanced Ply Laminates ......................................................... 183 7. I-BEAMS................................................................................................................... 184 Experimental Investigation Of Beam Static and Fatigue Behavior................... 185 Material and Beam Description......................................................................... 187 Studies of Beams with Triax Material Flanges ................................................. 191 Behavior of Beams................................................................................. 193 Studies of Beams with Improved Flange and Web Materials ............................199 Material Development and Coupon Results ......................................... 200 Beam Test Results................................................................................. 200 Conclusions for Beams With Improved Flange and Web Materials .. . 207 Stiffness Changes..................... 208 Studies Of Structural Details............................................................................. 213 Effects of Through-Thickness H oles..................................................... 213 Coupon Results With Holes ....................................................................214 Beam Results With Holes ..................................................................... 219 Beams Utilizing a Balsa Wood C ore ..................................................... 220 Conclusions for I-beam Study ........................................................................... 222 8. CYLINDRICAL TUBES........................................................................................... 224 Static 4-Point Bending T es ts ............................................................................. 225 Static and Fatigued Cantilever Beam T ests ....................................................... 239 Comparison with Coupon Tests.......................... : ........................................... 250 Conclusions for Cylindrical Tubes ................................................................... 253 9. CONCLUSIONS AND RECOMMENDATIONS ................ ............................... 254 High Cycle Fatigue Behavior of Glass Strands................................................254 Reinforcement Fabric Architecture Effects....................................................... 255 Fiber Content..................................................................................................... 257 Content of Fibers in the Loading Direction....................................................... 257 Matrix Materials................... 258 Optimum Laminates for Blade Primary Structure........................................ :. 259 I-Beams ............................................ .'............................................................. 259 Cylindrical Tubes........................................................... 260 Recommendations .............................................................................................260 i REFERENCES .............. 262 APPENDICES............................................ : ............................................................... 270 Appendix A - DOE/MSU Composite Material Fatigue Database..................... 271 Appendix B - Summary of I-Beam Tests.......................................... 448 vii vm 2.1. Summary of E - Glass fabrics.............................................................. ................... 11 2.2. Summary of resin matrix materials..........................................................................11 2.3. Summary of test coupon geometries........................................................................17 2.4. Summary of Tab Materials......................................................................................20 2.5 Summary of web I-shapes used in Beams 6 through 59.............................................23 2.6. Summary of additional beam components ............................................................. 24 3.1. Summary of mechanical testing equipment ............................................................. 30 3.2. Summary of Load ce lls ............................................................................................. 31 3.3. Summary of extensometers....................................................................................... 32 3.4. Summary of strain gages........................................................................................... 34 3.5 Summary of applicable bending standards for uniaxial testing machines................36 5.1. Summary of previous fatigue results on individual E-glass fibers and tows ........’.80 5.2. Impregnated strands tested in fatigue......................................................................82 5.3. Summary of fatigue properties for the unidirectional materials tested ..................89 5.4. Summary of static properties for the unidirectional materials tested......................95 5.5. Summary of the ±45° materials tes ted ................................................................... 102 5.6. Summary of materials with 16 to 63 percent 0’s................................................ 109 5.7. Summary of materials with 69 to 85 percent 0° plies............................................110 5.8. Lay-up summaries with 55 to 63 percent 0° plies...................................................119 5.9. Summary of fatigue results: tensile (R = 0.1), compressive (R = 10) and reversed loading (R = -I)................................................................................... 125 LIST OF TABLES 6.1. Measured angles of 0/±45 and ±45 materials listed in the database....................... 147 6.2. Properties of MSU manufactured (RTM) fiberglass materials with balanced angle plies........................................................................................... 149 6.3. Tension and compression test coupon gage lengths................................................151 6.4. Ply properties used in the laminate theory analysis (static) and values used for million cycle fatigue predictions adjusted to a fiber volume fraction of 0.39. .' 159 6.5. Failure criterion failure mode predictions for the balanced angle ply laminates with a fiber volume fraction of 0.39...................................................................165 7.1. Static and fatigue data for beams with AA flanges and material CHlO webs. . . . . 188 7.2. Static and fatigue data for beams with DD5P flanges and CHlO webs....................189 7.3. Fatigue data for beams with DD5P flanges and CH3 webs......................................189 7.4. Static and fatigue data for beams with DD5P flanges and CH12 webs....................190 7.5. Fatigue data for beams with DD5P flanges and DD5P webs....................................190 7.6. Fatigue data for beams with DD22 flanges (with balsa wood), and CH12 webs. . 190 8.1. Summary of static four - point bending tests performed on tube sections . : ......227 ix 8.2. Test summary for tubes T120 through T137 242 LIST OF FIGURES 1.1. Modified Bergey 10 kW wind turbine at Rice Ridge Renewable Energy Park........ 1.2. Maximum recorded turbine blade strains, Bergey 10 kW, 7.5 m/s wind speed. . . . 1.3. AOC 15/50 wind turbine........................................................................................... 1.4. Typical wind turbine blade cross sections................................................................. 2.1. D155 fabric................................................................................................................ 2.2. A130 fabric................................................................................................................ 2.3 DB 120 fabric.......................................................................... ................................. 2.4. Lamina (plies) and laminate description................................................................... 2.5. Flat plate RTM mold. .............................................................................................. 2.6. Test coupon geometries............................................................................................. 2.7. Instron 8511 and 8872 test coupon geometry................... ....................................... 2.8. C-Channel RTM mold.............................................................................................. 2.9. Web !-section RTM mold......................................................................................... 2.10. Assembled I-beam................................................................................................... 2.11. Cylindrical tube RTM mold.................................................................................... 2.12. Aluminum 2024-T3 tube end fittings. . : .............................................................. 2.13. Tube testing assembly............. ............................................................................... 2.14. Fiber volume content versus RTM composite thickness......................................... 3.1. Strain gage photograph showing tensile strain cracks............................................... 3.2. Clip strain gage......................................................................................................... 3.3. High frequency strand testing apparatus and test coupon geometry......................... . 3 .4 .4 . 6 . 8 . 8 . 8 10 13 19 20 21 22 23 26 26 27 28 34 36 39 4.1. Constant stress amplitude sine waveforms for different R values............................ 41 4.2. Stress-strain curves for material DD5P at different testing rates.............................. 42 4.3. Tensile strength versus testing displacement rate (25 mm wide coupons with a 100 mm gage length)........................................... ..................................... 43 4.4. Tensile strength versus coupon width (100 mm gage length, 13 mm/s testing rate)...........................................................................................................43 4.5. ASTM D3039 tensile test coupon geometry............................................................. 46 4.6. Width tapered coupon (DD5P material) with shoulder splitting...............................48 4.7. Grip damage in test coupons, with and without tabs.................................................49 4.8. Tensile fatigue damage present under tab material......................................... .... 50 4.9. Instron hydraulic wedge grip cross section......................................... ..................... 50 xi 4.10. Applied axial load to the test coupon versus the grip body hydraulic pressure. . . . 51 4.11. Applied axial tensile load versus the hydraulic grip clamping force on the test coupon..................................................: ................................................. 52 4.12. Steel wedge grip face contact area with the test coupon. Shown by pressure film........................................................................................53 4.13. Hydraulic grip head translation versus side loading force...................................... 57 4.14. Anti-translation and anti-rotation devices..................................... ......................... 57 4.15. Typical compressive stress-strain curves with back-to-back strain gages.............. 58 4.16. Material compressive strength versus testing displacement rate (25 mm wide test coupons with a 13 mm gage length).............................................................. 58 4.17. Apparent compressive strength versus coupon width (13 mm gage length with a 13 mm/s testing rate).................................................................................59 4.18. I-beam four-point bending test set-up..................................................................... 60 4.19. Cylindrical tube cantilever beam testing set-up 62 Xll 5.1. Fiber volume fraction versus the average fiber spacing in a composite with theoretical square and hexagonal packing geometries......................................... 65 5.2. Fiber volume fraction versus the normalized maximum principal stress for a transversely loaded composite............................................................................ 66 5.3. Micrographs of prepreg and D155 fabric composites............................................... 68 5.4. Composite fiber volume content versus D155 confined fiber tow area in Materials DD6, DD2 and DD7.............................................................................. 69 5.5. Composite fiber volume fraction versus average number of fibers in contact with each other for materials DD6, DD5, DD2, DD9 and DDlO........................ 70 5.6. Stacking geometries of unidirectional fiber bundles.................................................72 5.7 Fabric stitching interaction with adjacent plies........................................................73 5.8. Fabric stitching interaction with adjacent ply stitching and the effects of removing the stitching........................................................................................... 74 5.9. A130 fabric with woven architecture with cracking around thermoplastic bead in coupon DDl 1-107 after fatigue testing................................................... 75 5.10. Normalized S-N fatigue data for unimpregnated single glass fibers........................ 81 5.11. Normalized S-N fatigue data for unimpregnated glass fiber strands, R = 0.1..........81 ■ 5.12. Normalized S-N fatigue data for impregnated glass fiber strands, R = 0.1..............82 5.13. S-N fatigue data for impregnated fiber strand, R = 0.1...........................................83 5.14. Normalized S-N fatigue data for impregnated fiber strand, R = 0.1.......................83 5.15. Applied tensile load versus time for a 45 fiber test coupon.................................... 84 5.16. S-N fatigue data for D155 impregnated fiber strand, R = 0.1................................. 84 5.17. Normalized S-N fatigue data for impregnated D155 fiber strand, R = 0.1............. 85 5.18. Strength distributions for strands from individual D155 rolls with Weibull fit parameters........................................................................................................85 5.19. Weibull distribution of pooled D155 strand ultimate tensile strengths from rolls I through 6......................................... ......................................................... 86 5.20. S-N fatigue data for D155 strands from D155 rolls 4 and 5................................... 87 5.21. Schematic representation of the development of damage during the fatigue - life of a multidirectional composite laminate.......................................................88 5.22. Normalized fatigue data for fabrics D072 and D092, R = 0.1................................ 90 5.23. Maximum initial fatigue strain data for fabrics D072 and D092, R = 0.1.............. 90 5.24. Normalized fatigue data for D155 fabrics (with and without stitching), R=0.1. .. 91 5.25. Maximum initial fatigue strain for D155 fabrics (with and without stitching), R = 0.1.............................................. ................................................................... 91 5.26. Normalized fatigue data for woven fabrics, R = 0.1............................................... 92 5.27. Maximum initial fatigue strain data for woven fabrics, R = 0.1. . .•......................92 5.28. Normalized fatigue data for industrial materials A, B and L (with and without thickness tapering), R = 0.1.................................................... 94 5.29. Maximum initial fatigue strain data for industrial materials A, B and L (with and without thickness tapering), R = 0.1.................................................... 94 5.30. Fiber tensile strength versus fiber content for unidirectional materials.................. 95 5.31. Ultimate compressive stress versus fiber volume for unidirectional materials. . . . 96 5.32. Compressive failure strain versus fiber volume for unidirectional materials......... 97 5.33. Million cycle tensile strain versus fiber volume for unidirectional materials, R=0.1..................................................................................................................... 99 5.34. Tensile fatigue coefficient, b, versus fiber volume for unidirectional materials. . . 99 5.35. Normalized compressive fatigue data for various unidirectional materials, R= 10.................................................................................. 100 5.36. Comparison of maximum initial fatigue strain data for various unidirectional materials and impregnated strand tests, R = 0.1................................................. 100 xiii 5.37. Normalized Fatigue SN data for materials with DB 120 ±45 fabric (R=0.1 and 10)................................................................................................... 103 5.38. Initial fatigue strain data for materials with DB 120 ±45 fabric (R=0,1 and 10). .103 5.39. Initial fatigue strain data for materials with DB240 ±45 fabric (R=0.1 and 10). . 104 5.40. Initial fatigue strain data for materials with DB400 ±45 fabric (R=0.1 and 10). .104 5.41. Normalized fatigue SN data for ±45 composites constructed with D155 fabric and different matrix materials (R=0.1 and 10).........................................105 5.42. Initial fatigue strain data for ±45 composites constructed with D155 fabric and different matrix materials (R=0.1 and 10)..........................................................105 5.43. Million cycle strain versus fiber volume fraction for ±45 materials.....................106 5.44. Tensile fatigue coefficient, b, versus fiber volume fraction for ±45 materials. . . 106 5.45. Normalized S-N fatigue data for materials with 16 percent 0° plies, [±45/0/±45]s layup with D092 and DB240 fabrics, R=0.1 and 10.....................I l l 5.46. Maximum initial fatigue strain data for materials with 16 percent 0° plies, [±45/0/±45]s layup with D092 and DB240 fabrics, R=0.1 and 10.....................I l l 5.47. Normalized S-N fatigue data for materials with 24 percent 0° plies, [±45/0/±45]s layup with D155 and DB240 fabrics, R=0.1 and 10.................... 112 5.48. Maximum initial fatigue strain data for materials with 24 percent 0° plies, [±45/0/±45]s layup with D155 and DB240 fabrics, R=0.1 and 10.................... 112 5.49. Normalized S-N fatigue data for materials with 28 percent 0° plies, [±45/0/±45]s layup with D092 and DB 120 fabrics, R=0.1 and 10.................... 113 5.50. Maximum initial fatigue strain data for materials with 28 percent 0° plies, [±45/0/±45]s layup with D092 and DB 120 fabrics, R=0.1 and 10.....................113 5.51. Normalized S-N fatigue data for materials with 39 percent 0° plies, [±45/0/±45]s layup with D155 and DB 120 fabrics, R=0.1 and 10.....................114 5.52. Maximum initial fatigue strain data for materials with 39 percent 0° plies, [±45/0/±45]s layup with D155 and DB 120 fabrics, R=0.1 and 10.....................114 xiv XV 5.53. Normalized S-N fatigue data for materials with 50 percent 0° plies, [±45/0/]n layup with stitched triax fabrics, R=0.1 and 10..................................115 5.54. Maximum initial fatigue strain data for materials with 50 percent 0° plies, [±45/0]n layup with triax fabrics, R=0.1 and 10................................................ 115 5.55. Normalized S-N fatigue data for materials with 55 to 63 percent 0° plies, R=0.1....................................................................................................................116 5.56. Maximum initial fatigue strain data for materials with 55 to 63 percent 0° plies, R=0.1.................................................................... 116 5.57. Million cycle tensile strain data versus fiber volume fraction for materials with 19 to 63 percent 0° plies, R=0.1................................................................ 117 5.58. Tensile fatigue coefficient, b, versus fiber volume fraction for materials with 19 to 63 percent 0° plies, R=0.1.................................................................118 5.59. Normalized S-N fatigue data for materials with 72 to 85 percent 0° plies...........119 5.60. Maximum fatigue strain versus cycles for material DD5P, R = 0.1, 10 and -I. . . 121 5.61. Maximum fatigue stress versus cycles for material DD5P, R = 0.1, 10 and-I. ..121 5.62. Tensile fatigue data for various MSU and industrial materials, R = 0.1................ 123 5.63. Extremes of normalized S-N tensile fatigue data (R = 0.1) for fiberglass laminates with at least 25 percent of the fiber in the 0° direction..................... 123 5.64. Normalized compressive fatigue data for standard coupons with 25 percent or greater percent 0° fibers, R=IO.......................................................124 5.65. Reversed loading fatigue data normalized by the compressive strength for materials with 25 percent or greater percent 0° fibers, R = -1..................... 124 5.66. reversed loading fatigue data normalized by the tensile strength for materials with 25 percent or greater 0° fibers, R = -1........................................125 5.67. Strain fatigue data for [±45]s and [0/±45/0]s materials, R=0.1.............................128 5.68. Effect of fiber content on the normalized S-N data, R=0.1, for DD materials [0/±45/0]s........................................................................................................... 129 (5.69. Fiber content versus fatigue sensitivity coefficient, b, for DD materials..............129 5.70. Initial strain for IO6 cycles (R = 0.1) versus percent 0° plies, D155, CH and DD materials......................................................................................... 130 5.71. Comparison of tensile fatigue test coupons, unidirectional Material A.............. 132 5.72. Unidirectional materials based on A130 fabric.....................................................132 5.73. Unidirectional low fiber content materials based on D155 fabric........... ' ............ 133 5.74. Unidirectional high fiber content materials based on D155 fabric....................... 133 5.75. Material GG showing heavy brooming upon failure, tensile fatigue.................... 134 5.76. Material CH9 coupon failures...............................................................................134 5.77. Low fiber content, low percent 0’s coupon failures................................................135 5.78. High fiber content, low percent 0’s coupon failures...............................................135 5.79. Moderate fiber content and percent 0’s coupon failures..................................... 136 5.80. Standard structural material at low fiber content, 72% 0’s coupon failures......... 136 5.81. Standard structural material with 72% 0’s coupon failures.................................... 137 5.82. Standard structural material at moderate fiber content coupon failures................. 137 5.83. Standard structural materials at higher fiber content coupon failures.................... 138 5.84. Photographs of unidirectional stitched and adhesively bonded fabrics................ 141 5.85. Photographs of woven unidirectional and stitched ±45° fabrics.......................... 142 5.86. Photographs of stitched Triax fabrics................................................................... 143 6.1. Tensile stress - strain curves for balanced ±10°, ±20°, ±30°, and ±33° angle ply laminates (D155 fabric, Vf = 0.39).....................................................153 6.2. Tensile stress - strain curves for balanced ±40°, ±45°, and ±50° angle ply laminates (D155 fabric, Vf = 0.39).............................................................. 153 xvi (6.3. Tensile stress - strain curves for balanced ±60°, ±70°, ±80° and 90° angle ply laminates (D155 fabric, Vp = 0.39).....................................................154 6.4. Ultimate tensile failure strain versus balanced ply angle........................................ 155 6.5. Compressive stress - strain curves for balanced ±10°, ±20°, ±30° and ±40° angle ply laminates..................................................................................... 156 6.6. Compressive stress - strain curves for balanced ±50°, ±60°, ±70° and 90° angle ply laminates.................................................................................157 6.7. Calculated average ultimate compressive failure strain versus ply angle............... 157 6.8. Longitudinal elastic modulus versus laminate theory predicted values.................. 159 6.9. Major Poisson’s ratio versus laminate theory predicted values.............................. 160 6.10. Calculated shear modulus versus balanced ply angle........................................... .160 6.11. In - plane laminate stresses versus balanced ply angle...........................................161 6.12. Ultimate tensile strength versus balanced ply angle with laminate theory predicted values from the maximum stress, maximum strain and quadratic failure theories..................................................................................................... 164 6.13. Ultimate compressive strength versus balanced ply angle with laminate theory predicted values from the maximum stress, maximum strain and quadratic failure theories......................................................................................164 6.14. First cycle hysteresis loops for balanced angle ply laminates from ±10° to 90° with a maximum stress equal to 50% of the laminates UTS........................166 6.15. Hysteresis energy generated on the first cycle for angle ply laminates from 0° to 90°with a maximum stress equal to 50% of the laminates UTS.............. 167 6.16. Tensile fatigue stress versus cycles to failure data for balanced ±10° to ±50°laminates (±[0]3 laminates with D155 fabric, Vp = 0.39).......................... 169 6.17. Tensile fatigue strain versus cycles to failure data for balanced ±10° to ±50°laminates (±[0]3 laminate with D155 fabric, Vp = 0.39)...........................169 6.18. Tensile fatigue stress versus cycles to failure data for balanced ±60° to 90°laminates (±[0]3 laminate with D155 fabric, Vf = 0.39)............................. 170 xvii 6.19. Tensile fatigue strain versus cycles to failure data for balanced ±60° to 90“laminates (±[0]3 laminate with D155 fabric, Vf = 0.39).............................. 170 6.20. One million cycle tensile fatigue failure strain versus balanced ply angle with laminate analysis predicted first ply static cracking strain and predicted million cycle strain. (±[0]3 laminate with D155 fabric, Vf = 0.39, R = 0.1). ..171 6.21. Tensile fatigue coefficient, b, versus balanced ply angle......................................171 6.22. Compressive fatigue stress versus cycles to failure data for balanced ±30° to 90“laminates (±[0]3 laminate with D155 fabric, Vp = 0.39).................172 6.23. Calculated compressive fatigue strain versus cycles to failure data for balanced ±30° to 90“laminates.................................................................... 172 6.24. One million cycle compressive fatigue strain versus balanced ply angle with laminate analysis predicted first ply static cracking strain and predicted million cycle fatigue strain. .............................................................. 173 6.25. Compressive fatigue coefficient, b, versus balanced ply angle.............................173 6.26. Failed tensile fatigue coupons from ±10° to ±30° laminates showing delamination and cracking of plies with edge effects........................................ 176 6.27. Failed tensile fatigue coupon 20D155112 ..........................................................177 6.28. Failed tensile fatigue coupons from ±40° to ±45° laminates showing delamination and cracking of plies.'..................................................................178 6.29. Failed tensile fatigue coupons from ±60° to 90° laminates showing cracking of plies............................... ."............................................................... 178 6.30. Failed compressive fatigue coupons from ±30° to ±40° laminates showing cracking and shearing of plies............................................................. 180 6.31. Failed compressive fatigue coupons from ±50° to 90° laminates showing cracking and shearing of plies............................................................. 180 6.32. Static tensile failure of ±10°, ±20° and ±30° coupons showing lamina cracks parallel to the fiber direction...................................................................181 6.33. Static tensile failure of ±40°, ±45° and ±50° coupons showing lamina cracks parallel to the fiber direction and delaminations causing matrix yielding and fiber movement............................................................................. 182 xviii 6.34. Static tensile failure of ±60°, ±70°, ±80°and 90° coupons showing lamina cracks parallel to the fiber direction....................................................... 182 7.1 Sketch and photograph of composite I-beam...........................................................186 7.2. Fatigue data for materials AA and DD5P, R = 0.1..................................................192 7.3. Fatigue data for materials AA and DD5P, R=IO...................................................192 7.4. Fatigue data for materials CH3, CH10, CH12 and DD5P, R = 0.1.......... 193 7.5. Fatigue data for material AA, R = 0.1 and 10...........................................................195 7.6. Beams 6 -14, 22 and 23 with material AA flanges and material CHlO web compared with material AA coupon fatigue data....................................... 195 7.7. Beams 6 - 14, 22 and 23 with material AA flanges and material CHlO web. Compensated for flange thickness compared with CHlO coupon fatigue data. 196 7.8. Tensile and compressive flanges of failed beams with material AA flanges and material CHlO webs.................................... 197 7.9. Beam 13 static compression flange failure..............................................................198 7.10. Beam 8 tension flange failure., ............................................................................. 198 7.11. Beam 14 tension flange fatigue failure.............................................................. .199 7.12. Beams 18-21 and 24 - 29 with material DD5P flanges and material CHlO web compared with material DD5P coupon fatigue data........................ 202 7.13. Beams 18 - 21 and 24 - 29 with material DD5P flanges and material CHlO web compensated for flange thickness compared with material CHlO coupon fatigue data.................................. 202 7.14. Photograph of web from Beam 10 showing extensive cracking of the web near tension flange...............................................................................................203 7.15. Tension flanges of failed beams with material DD5P flanges and material CH3 webs............................................................................................................ 203 7.16. Beams 30 - 33 with material DD5P flanges and material CH3 web compared with DD5P coupon fatigue data..........................................................204 xix 7.17. Beams 30 - 33 with material DD5P flanges and material CH3 web compensated for flange thickness compared with CH3 coupon fatigue data. . . 205 7.18. Beams 34 and 35 with material DD5P flanges and material CH12 web compared with material DD5P coupon fatigue data.................'.........................205 7.19. Beams 34 and 35 with material DD5P flanges and material CH12 web compensated for flange thickness compared with CH12 coupon fatigue data. . 206 7.20. Beams 51-54 with DD5P flanges and web compared with DD5P coupon fatigue data.......................................................................................................... 206 7.21. Tension and compression flanges of failed beams with material DD5P flanges and webs.,............................................................................................... 207 7.22. Shear stress XY at the adhesive interface of flanges (17.8 kN load).....................209 7.23. Shear stress XZ at the adhesive interface of flanges (17.8 kN load).....................210 7.24. Shear stress YZ at the adhesive interface of flanges (17.8 kN load )...................211 7.25. Normalized Von Mises stress on the centerline of the beam................................ 212 7.26. Matrix cracking at tensile flange in Beam 28 (x = 178 mm) at delamination initiation location.................................................................................................212 7.27. Beam stiffness versus lifetime................................................................................214 7.28. Tensile fatigue data for material AA coupons with and without a 13 mm diameter hole, R = 0.1......................................................................................... 215 7.29. Tensile fatigue data for material AA coupons with and without a 13 mm diameter hole, R = 0.1......................................................................................... 216 7.30. Normalized tensile fatigue data for material AA coupons with and without a 13 mm diameter hole, R = 0.1.........................................................................216 7.31. Compressive fatigue data for material AA coupons with and without a 13 mm diameter hole, R = 10.............................................................................. 217 7.32. Fatigue data for material AA coupons with and without a 13 mm diameter hole, R = -1.......................................................................................................... 217 XXl 7.33. Damage around the 13 mm diameter hole versus fatigue lifetime.................... '. . 218 7.34. Photograph of damage around the 13 mm diameter hole at different stress levels, R = 0.1.................................................................... ..218 7.35. Delamination on a compression fatigue coupon (coupon 127 A A)....................... 219 7.36. Comparison of AA material flange beams without holes to AA beams with 13 mm diameter holes in the flanges......................................................... 220 7.37. Comparison of AA material flange beams with holes to AA material coupons with 13 mm diameter holes..................................................................221 7.38. Beam 15 with holes, static compression flange failure.........................................221 8.1. Hollow cylindrical tapered tube geometry.............................................................. 225 8.2. Bending moment versus bending strain for Tl 10................................................... 228 8.3. TllO failed tube surface.............................................. ........................................... 228 8.4. Bending moment versus bending strain for Tl 11................................................... 229 8.5. Tl 11 failed tube surface..........................................................................................229 8.6. Bending moment versus bending strain for Tl 12................................................... 230 8.7. Tl 12 failed tube surface..........................................................................................230 8.8. Bending moment versus bending strain for Tube Tl 13.......................................... 231 8.9. Tl 13 failed tube surface..........................................................................................232 8.10. Bending moment versus bending strain for Tl 14............... ................................. 232 8.11. Tl 14 failed tube surface........................................................................................233 8.12. Bending moment versus bending strains for Tl 15................................................233 8.13. Tl 15 failed tube surface........................................................................................235 8.14. Bending moment versus bending strains for Tl 16............................................... 235 8.15. Tl 16 failed tube surface........................................................................................236 8.16. Bending moment versus bending strains for Tl 17............•.................................. 236 8.17. Bending moment versus bending strains for Tl 18................................................237 8.18. Tl 18 failed tube surface........................................................................................237 8.19. ’Bending moment versus bending strains for Tl 19.............................................238 8.20. Tl 19 failed tube surface...................................................... '.................................238 8.21. Cantilever tube end fixture failures.......................................................................239 8.22. Normalized maximum bending stress vs. position on the tube.............................241 8.23. T121 failed tube surface................................................................ ....................... 243 8.24. T122 failed tube surface........................................................................................243 8.25. T123 failed tube surface........................................................................................244 8.26. T124 failed tube surface........................................................................................244 8.27. T126 failed tube surface....................... ■...............................................................245 8.28. T129 failed tube surface....................................................... 245 8.29. Bending strain versus bending stress for T122.......................................................246 8.30. Polished end of T130 showing adhesive cracking..................................................247 8.31. T137 fixed end support showing extensive cracking. ............................................248 8.32. T130 fixed end support showing cracking. ............................................................248 8.33. Axial stress in the gage length versus axial strain for tube T130 tested in uniaxial tension after 1,800,000 bending fatigue cycles................................ 249 8.34. Axial stress in the gage section versus axial strain for tube T133, tested in uniaxial tension without prior fatigue testing................................................ 249 8.35. Fixed end of tube T134 showing a metal fatigue crack after 3,200,000 cycles. .. 250 xxii XXlll 8.36. Tubes T120 - T137 compared with material DD5P Tensile (R=OT) and Compressive (R=IO) coupons............................................................................. 251 8.37. Compressive fatigue data for Tubes T120 - T137 compared with material DD5P compressive (R=IO) coupons................................................................... 252 8.38. Normalized compressive fatigue data for Tubes T120 - T137 compared with material DD5P compressive (R=IO) coupons............................................. 252 XXlV ABSTRACT Fiberglass composites have been used in thousands of applications since their inception in the late 1930's despite an incomplete understanding and characterization of their mechanical fatigue properties. Wind turbine blades, which are the main focus of this research, experience between IO8 to IO9 significant fatigue (loading-unloading) cycles in their 20 to 30 year lifetime, and fatigue is a major factor in their design. This thesis presents a detailed analysis of the DOE/MSU Composite Material Fatigue Database, which has been developed over the last nine years. The database currently includes over 6000 static and fatigue test results covering 148 different fiberglass materials and numerous loading conditions. Trends in fatigue resistance with various materials and loading parameters are explored, including: reinforcement fabric architecture, fiber content, content of fibers orientated in the load direction, matrix material and loading conditions (tension, compression and reversed loading). The results show unexpected transitions in fatigue resistance with fiber content and fabric architecture. Transitions to increased fatigue sensitivity have been related to fiber packing characteristics through detailed microscopy study. Material characteristics which produce maximum fatigue resistance have been established. Very high cycle tensile fatigue behavior (109 cycles) has been explored with a novel high frequency apparatus using impregnated strands. The strand data suggest a reduction in fatigue sensitivity in the IO8 to IO9 cycle range, but a material endurance limit has not been seen. Larger impregnated glass strands tested in excess of IO8 cycles using conventional testing equipment provide similar results to the smaller strands. The study has also explored the application of the database to the prediction of the fatigue response of small composite substructures representative of wind turbine blades. Thirty six I-beams were tested under four-point bending. The beams were constructed of materials which showed a range of fatigue resistance in the materials coupon tests. The coupon database accurately predicted the performance of the beams when the failure modes were predominately tensile or compressive. Delamination of the tensile flange in the beams with improved fatigue resistance materials, due to the increase in bending loads and flange operating strains, provided less conclusive results. The effect of flaws (through-thickness holes) was also explored. A second geometry, hollow tubes, was also explored in conjunction with field tests on a small wind turbine. Twenty seven hollow tube test sections were tested under four-point and cantilever bending. Due to the hollow tube geometry, the compressive buckling behavior was the limiting static design parameter, and the obtained compressive strains in the tubes were slightly lower than the database compressive strength values (which used very short specimens). ICHAPTER I INTRODUCTION The selection of a material and prediction of the service lifetime for a fatigue dominated structural design, whether using metal, plastic, or composite, is one of the most difficult tasks faced by an engineer. Glass fiber reinforced plastics (GFRP) have been available for over 60 years and are presently incorporated into thousands of different applications ranging from consumer products to aerospace applications. However, fatigue research is time consuming and costly, and generally has been limited to the high technology areas, such as aerospace and defense, which can support these costs. The availability of fatigue data for the wide variety of GFRP materials has generally been very limited compared with carbon fiber composites used in aerospace. Furthermore, much of the available fatigue data for GFRP is flawed hysteretic heat generated failures at high frequencies using thick materials, and very few results are at lifetimes greater than IO6 cycles for any composite system. This lack of fatigue information has led to apparent fatigue failures and overly conservative designs. Wind turbine blades, such as those shown on the Bergey Excel 10 KW machine in Figure 1.1, operate at up to 300 rpm and typically experience more than IO9 rotations over their 20 to 30 year design lifetime. Typical Complex fatigue loading which occurs in 2these blades is shown in Figure 1.2, recorded on the experimental Bergey Excell 10 kW machine at the Rice Ridge Renewable Energy Park operated by Montana Tech of the University of Montana and Montana State University-Bozeman. Figure 1.3 shows an Atlantic Orient Corporation (AOC) 15/50 wind turbine whose blades have been a focus of portions of the present study; this turbine has been installed at the Madison Valley Distributed Generation Demonstration site. Most wind turbine designs use relatively heavy, stiff blades which are designed to operate at maximum strains in the range of a few tenths of a percent, at most. While this approach may be necessary for the poorest of the GFRP material systems, it results in costly, inefficient blades compared with the best material systems found in the present study. Variables which are generally manipulated in GFRP material systems include: fabric reinforcement type, fiber orientation angle, matrix material, fiber volume fraction and laminate lay-up (the sequence of plies of varying orientation). There is also a range of loading parameters to be studied, including various combinations of tension and compression cycling (R value), high and low cycle ranges, and spectrum loading with varying loads on each cycle. The main focus of this research has been the development of a GFRP fatigue database including the materials and loading parameters of interest to the wind turbine blade application. Also, specialized strand tests are used to achieve higher cycle data than has been previously reported. (It must be noted that wind turbine blades are one extreme application of this fatigue research. Materials constructed and discussed in the database could be applied to any other structural component.) Most of this research has been 3summarized in References I through 17. The database related study has also been extended to small substructural elements, typical of wind turbine blades, which are shown in Figure 1.4. These blades can range in length from 3.3 m for the 10 KW Bergey Excell to 49 m for the 3.2 MW Boeing Aerospace turbine [18]. Reference [18] is a good overview of present wind turbine technologies and their fundamental operating principles. These turbine blades have an aerodynamic structural skin with internal stiffeners and spars which increase the rigidity of the blade structure. Figure 1.1. Modified Bergey 10 kW wind turbine at Rice Ridge Renewable Energy Park. Insert shows special test section with tube specimens at the blade root. 4Edge % strain XlOO Flap % strain XIOO 50 - - 40 30 - Axial % strain XlOO —- ^W r Time, seconds Figure 1.2. Maximum recorded turbine blade strains, Bergey 10 kW, 7.5 m/s wind speed. Figure 1.3. AOC 15/50 wind turbine. 5The geometry and manufacturing of composite structures of this type can strongly affect the performance of composite materials relative to simple test coupons used in the database. Thus, this study has also included tests on a number of structural details and substructures typical of blades, to explore the structural performance relative to predictions from the database. Substructures included in this study are structural details, such as ply drops for thickness tapering, incorporated into test coupons, as well as structural geometries including hollow cylindrical tubes and I-beams. Future work will include full scale 8 m long AOC 15/50 blades which incorporate these substructures and details. Due to the large amount of data presented in the DOE/MSU Wind Turbine Blade Composite Material Fatigue Database (hereafter referred to as “the database”), it is suggested that the reader become familiar with the introductory comments of the database presented in Appendix A. Generation of data for the database involved performing over 6,000 fatigue tests over a time period of approximately nine years, with many additional substructure tests. The author hopes to focus the reader on the most significant aspects of the database, fatigue testing and the mechanical fatigue behavior of fiberglass structures. 6NREL 9.6 m long airfoil blade section 140 cm AOC 15/50, 8 m long, typical cross section 81 cm Smaller blade cross section 3 > 35 cm Figure 1.4. Typical wind turbine blade cross sections. 7CHAPTER 2 FABRICATION OF MATERIALS All of the materials manufactured at MSU for this study involved resin transfer molding (RTM). This process produces a composite with uniform thickness, excellent fiber wet out, low porosity and negligible fiber Wash. It can also be used to produce materials typical of related processes, including hand lay-up used for many commercial blades. The process allows easy manipulation of ply lay-up and fiber volume content and produces more consistent material characteristics as compared to hand lay-up. A rigid and consistent approach to manufacturing was adopted from the start of the program and was applied to the RTM process to ensure consistent results. Fabric Reinforcement Stranded fabrics are available in a variety of stitched and woven architectures with varying strand (tow) size and fabric tightness. Examples of these fabric architectures are shown in Figures 2.1, 2.2 and 2.3 from Owens Corning Fabrics (formerly Knytex). Figure 2.1 shows a D155 unidirectional fabric which has a transverse (weft direction), polymer thread chain stitched to keep the fabric together. Figure 2.2 shows an A130 woven unidirectional fabric. These strands are woven over a transverse polymer thread coated 810 mm Figure 2.2. A 130 fabric. 10 mm Figure 2.3 DB 120 fabric. 9with a thermoplastic adhesive which is melted and holds the architecture together. Figure 2.3 shows a DB 120 fabric which is a stitched ±45° fabric. The +45° and-45° fabrics are individually stitched with a polymer thread and then the two are stitched together to form the ±45° fabric. Thicker and multiple angled fabrics are also constructed using this process. The additional transverse stitching allows handling and placement of the fabrics with very little fabric movement or tow rotation. Laminates are constructed with individual layers (plies) or stitched multilayer fabrics as detailed in Figure 2.4. E-glass fabric reinforcement was provided by (or purchased from) Owens Corning Fabrics, Collins Craft Incorporated, and Brunswick Technologies Incorporated and was delivered on 127 cm wide'rolls. The fabrics were unrolled onto a table where rectangular patterns were cut using a standard rotary fabric cutter, with the O0 fibers in the long dimension to aid in resin flow and fiber wet out. Fabrics in most of this study were limited to 0°, ±45° and 0o/±45° stitched fabrics, which are summarized in Table 2.1. These rectangular cut fabric patterns were then placed in the RTM mold and stacked as per the specific ply arrangement desired. Resins Five different resins were used in this study: CoRezyn 63-AX-051, an unsaturated orthophthalic polyester resin obtained from Interplastic Corporation, Derakane 411-C-50 and Derakane 8084 (rubber modified) vinyl esters produced by Dow Chemical Company, Epon epoxy resin 9410 with 9450 Epon curing agent, a modified bisphenol “A” epoxy resin system and liquid MDA based aromatic amine curing system obtained from Shell 10 CT CT CT a = O0 a = +45° a = 90° 0° ply +45° ply 90° ply Laminate Stacking Sequence 4X [0/±45/0] Figure 2.4. Lamina (plies) and laminate description. Chemical Company, and a toughened epoxy (two-phase acrylate modified) system, SC- 14, obtained from Applied Poleramic Incorporated. The mixing and cure schedules are summarized in Table 2.2, as recommended by each respective manufacturer. Methyl Ethyl Ketone Peroxide (MEKP) was the catalyst used by both the CoRezyn and the Derakane 411C. The 41 IC and 8084 Derakane were the only resins which had to be promoted with cobalt naphthenate (CoNap) and dimethylaniline (DMA) prior to mixing with the MEKP catalyst. Trigonox 239A (2%) was substituted for MEKP in the Derakane 8084 which reduced the amount of foaming. Most of the RTM composites in this study involved the CoRezyn polyester resin, which is a common wind turbine blade manufacturing resin. The other resin systems were chosen for specific properties like toughness and heat resistance, and due to their wide commercial acceptance and general use in industry. The resin systems were initially stored at approximately -15 0C until needed. The resin was allowed to warm up to room 11 Table 2.1. Summary of E - Glass fabrics. E - glass fabric Description Total weight g/m2 Dry thickness mm Manufacturer A060 woven O0 206 0.35 Owens Coming Fabrics A130 444 0.53 A260 868 0.91 CDB200 0°/±45o 759 0.86 CM1701 0° plus mat 587 0.78 D072A stitched 0° 230 0.40 D092 310 0.48 D155 527 0.53 DB 120 45° 393 0.53 DB240 837 0.86 DB400 1,349 1.24 UC1018V 0° 620 0.52 Collins Craft TVM3408 0°/±45o 1,150 1.42 Brunswick Table 2.2. Summary of resin matrix materials. Resin Catalyst Promoter Cure cycle CoRezyn 63-AX-051 2% by vol. MEKP min. 4 hours in the mold +2 hours at 60°C Derakane 4 11 -C-50 1.5% by vol. MEKP 0.3% CoNap 0.05% DMA Derakane 8084 2% by vol. Trigonox 239A 6% CoNap min. 4 hours in the mold +2 hours at 60°C SC14 100:35 A:B mix ratio by weight 3 hours at 60°C +5 hours at IOO0C Epon 9410 Epon 9450 - 35% by weight 10 hours at 80°C 12 temperature, 18 to 22 0C, for 24 hours before mixing with MEKP or mixing the two component Epon system. For the CoRezyn, if the room temperature was greater than 25 0C, the percentage of MEKP was reduced to 1.5% to ensure a minimum 30 minutes before it gelled. The catalyzed resin was then pumped into the two center injection holes in the aluminum baseplate using a peristaltic pump (Cole-Parmer Instruments Company Model 7553) and silicone tubing. The resin was transferred to the mold over a 5 to 15 minute period, with pressures less than 150 kPa, depending upon fiber reinforcement lay up, angle and fiber volume. Approximately 50 ml of resin was allowed to flow out of the exit ports at each end of the mold to ensure that all the layers had been wet out. The pump was then stopped and the center injection ports were plugged. The resin exit ports at the ends of the mold were left open to equalize the resin pressure throughout the mold. This action prevented pressure induced deflection of the mold faces, which would vary the thickness of the composite plate. The CoRezyn and Derakane plates were removed from the mold after a minimum of four hours from the time of the MEKP addition and placed in a post cure oven at 60 0C for two hours. The Epon epoxy plates were injected and directly placed in an 80 0C oven for ten hours and then allowed to cool down slowly to room temperature overnight. References 19 and 20 provide a detailed discussion of the resin transfer molding process used here. Flat Rectangular Plate Construction The most common flat rectangular plate resin transfer mold used in this study consisted of a lower 13 mm aluminum baseplate with a gasket channel milled around its 13 perimeter, as shown in Figure 2.5. This channel allowed the placement of a 13 mm by 13 mm extruded Buna N (nitrile rubber) gasket. The relative height of the top of this gasket to the top of the baseplate could be changed by adding sheet metal spacers under the gasket, allowing the thickness of the composite plate to be changed. A 13 mm thick tempered glass plate acted as the top of the mold, allowing visual examination of the mold filling process as the resin was injected into the mold. A positive seal was produced between the glass, gasket and the aluminum plate with ten C-clamps. Steel blocks were placed between the C-clamp heads and the glass plate to provide a bearing surface and to prevent fracturing of the glass. The clamps were torqued to 35 cm-kg. This torque setting was established at the beginning of the project and provided reproducible composite plate thicknesses throughout the study. A second, fixed thickness mold was later constructed to manufacture larger composite plates with dimensions 51 cm x 81 cm and a thickness of 3.15 ±0.05 mm. I----------------------------- 85 cm --------------------------------1 Figure 2.5. Flat plate RTM mold. Both inside surfaces of the mold were coated with external mold release agent F- 57NC, from Axel Plastics Research Laboratories Incorporated or Frekote 700 - NC mold release agent by the Dexter Corporation. The aluminum plate was initially surface 14 polished with 600 grit emery paper which produced an excellent carrier surface for the mold release. The mold release was applied over both the aluminum and the glass surfaces using a small cloth and approximately 10 to 15 ml of mold release. The release agent was then air dried for 15 minutes producing a viable film which lasted for 30 to 40 plates. When this film was exhausted, the mold surfaces were cleaned with acetone and a new film layer was applied. For composite plates with fiber volume contents greater than 0.5 or fabrics with poor resin transfer channels, a special method of resin injection was developed. A special process was necessary, to prevent fiber wet out problems, fiber wash in the mold or injection pressures greater than 200 kPa, which was the capacity of the pumping system. A layer of double sided mounting tape (Scotch HO) was placed between the glass and the rubber gasket and initially, very lightly clamped (surface contact). The mold was then completely injected with resin before the C-clamps were torqued up to 35 cm-kg. This caused the foam tape to compress from 1.6 mm to approximately 0.4 mm, causing excess resin to flow out the vent ports of the mold. The maximum fiber volume fraction produced by this process was 0.67 with excellent fiber wet out with negligible porosity. E - Glass Prepreg Scotchply reinforced epoxy unidirectional prepreg, SP-250E, was also prepared as coupon tabbing material, as well as a comparison material to some of the RTM materials. The storage and processing conformed to 3M Aerospace specifications. The prepreg tape was stored at -15 0C and was allowed to warm up to room temperature before handling. 15 The tape was cut into 29 cm long strips and placed on a 30 cm by 30 cm aluminum plate where additional layers of prepreg were added to obtain the required lay-up and thickness. This prepreg preform was then transferred to two electrically heated platens in an Instron 8562 servo-electric testing machine. Teflon release film, bleeder cloth and a peel ply sheet were placed between the two heated platens and the prepreg preform. The platens were preheated to 120 0C. The preform was heated under contact pressure with the heated platens for five minutes. The pressure on the preform was slowly increased over an additional five minutes and finally held at 340 kPa. The temperature and pressure were held for a period of two hours. At the end of this period the prepreg plate was taken out of the heated platens and placed in a post-cure oven for an additional 14 hours at 120 0C. The plate was then taken out and allowed to cool down to room temperature. Industrial Supplied Materials Materials were supplied by various wind turbine blade manufacturers for fatigue testing and evaluation. Most of these materials were supplied as hand laid-up flat sheets, and one manufacturer supplied a pultruded turbine blade from which test coupons (material EE) were cut. In most cases, details of the resin systems or the reinforcing fabrics used in these industrial composites were not available. Machining The edges of the RTM, prepreg and industrial plates were trimmed off to eliminate any edge composition variability, ensuring representative, uniform material 16 properties. The trimmed plates were then cut to produce flat rectangular coupons for testing. The plates were cut into 25 mm or 38 mm wide strips depending upon the required coupon width. From these strips, at least two tensile and two compressive coupons were cut. This stratified random sampling scheme, with replication, was necessary to produce the required number of testing specimens and to achieve the required statistical confidence in the experimental design. The plates were cut with a 20 cm diameter diamond coated blade rotating at 3,450 rpm (36 m/s), which was water cooled and lubricated. The feed rate of the composite plates during cutting was less than approximately 5 mm/second to ensure clean, perpendicular cut edges. Coupons which had to be thickness or width tapered were dry machined with a three flute carbide router bit rotating at 23,000 RPM. The final test coupons did not undergo any form of edge surface modification or polishing, they were tested “as cut”. For materials which had a 12.7 mm diameter hole, the holes were drilled using a four step process. An originating locator hole was first drilled using a 3 mm diameter twist drill. This allowed for precise placement of the hole center and minimized the amount of drilling induced delamination damage. A second 7.9 mm diameter and a final 12.3 mm diameter twist drill followed. Final preparations involved polishing the circumference of the hole with 240, 400 and 600 grit polishing cloths. Test Specimen Geometries Determining accurate and representative material fatigue properties involved a number of tradeoffs. The material tests ideally would involve a representative material 17 volume, require low forces to test (which prevents load transfer problems and grip failures), a short gage length to achieve higher fatigue frequencies for a given hydraulic capacity and a gage area of uniform axial strain where the material modulus can be determined. Table 2.3 and Figure 2.6 summarize the nominal geometry of the test coupons with relation to the mechanical test to be performed. These developed geometries worked well in the static and fatigue tests performed on the MTS 880 and Instron 8501,8511,8872 and 1350 testing machines. The coupons tested in the Instron 8511 and 8872, due to the machine capacity, had to have smaller coupon cross sectional areas which are detailed in Figure 2.7. Additional tab material was added in the coupon gripping areas to reduce the stress concentration generated by clamping the coupon and to provide a wear surface between Table 2.3. Summary of test coupon geometries. Test % zero’s in composite Coupon geometry Materials Gage Length Static tensile and fatigue at R = 0.1 <50% rectangular, as cut A-Y, AA, CH, ±20°-90° 100 mm ±10° 160 mm 50% to 84% width tapered BE, CC, DD, FF, GG 135 mm 100% thickness tapered Axxx, Dxxx, CM 1701 100 mm Static compressive and fatigue at R = IO and R = -I All cases rectangular, as cut All cases 13 mm 18 the test specimen and the steel wedge grips. Additional tab material was bonded to the coupons, when necessary, as the last step in the manufacturing process. The tab material utilized in this study included electronic protoboard, fiberglass prepreg (0°/90o and ±45° lay-ups) and, with limited success, aluminum with chopped glass fiber mat. These are summarized in Table 2.4. Different tab materials and adhesives were tried in order to produce good failure modes in the gage length of the coupons while avoiding grip induced damage or failures. For tab material attachment, the areas of the coupon and the tab material surface were lightly roughened with 180 grit emery cloth, cleaned with a sponge and water, and air dried to produce clean bonding surfaces. Each surface was" then smeared with a thin layer (0.1 to 0.4 mm) of Hysol EA 9309.2NA adhesive and assembled. Paper binder clips, 50 mm wide, were used to apply pressure to the assembly and keep the tabs aligned. The assembly was then cured in a convection oven at 60 0C for two hours, as recommended by the adhesive manufacturers. This adhesive cure cycle also served as the coupon material post cure treatment. After curing, the clamps were removed and the tab faces were lightly sanded to remove any excess adhesive and to provide flat and parallel clamping surfaces. The coupons were labeled for identification with a unique material letter label and a sample number. The finished test coupon was then measured for its average and minimum cross sectional area in the gage length using a Mitutoyo Digimatic digital caliper, or equivalent, with a minimum resolution and accuracy of 0.01 mm. 19 - 200 mm 25 mm static tensile and R = 0.1 coupons ^ p*38 mm ►( tab material top view T 38 mm I 25 mm r ---------- -- I *1 static tensile and R = 0.1 coupons for width tapered coupons u— t 22 mm x^R - 280 mm i ....... - i tab material Ir--------- 1 Izivjw rum static tensile and R = O l coupons for thickness tapered coupons _____________________ i_____________________ i side view top view side view top view side view 0.6T h 25 mm 100 mm static compressive, R=IO and R = -I test coupons *- top view side view Figure 2.6. Test coupon geometries. 20 tab material 9 mm diameter 6 mm I 15 Top View \* 25 mm 1 ■75 mm Side View Figure 2.7. Instron 8511 and 8872 test coupon geometry. Table 2.4. Summary of Tab Materials. Material Description Protoboard Radio Shack catalog number 276-1396, 1.6 mm epoxy sheet with I mm diameter holes spaced 2.5 mm in a rectangular grid. Fiberglass1 Plastifab G 10, 1.6 mm, [0/90]7, Vf = 35%. With and without IO0 tapered ends. Fiberglass 3M SP250 prepreg, [±45]10, Vf = 55%. Aluminum 6061-T6, 2.5 mm with 10° tapered ends with resin impregnated chopped mat (170 g/m2) between the aluminum and the composite. 1 most common and most successful tab material used in this research I - Beam Construction Most of the developmental work on the composite I-beams and their initial construction was detailed by Combs [21] and involved Beams I through 5. The basic construction of the beams involved the resin transfer molding of two fiberglass C- channels, which were then secondary bonded together to form a I-shape. Flange material to be tested was then attached to this I-shape. For the C-channel mold, the glass fabric reinforcement was cut into 12 cm by 91 cm rectangular patterns and placed on the lower 21 external mold ring and gasket top glass plate injection ports gasket 25 mm “T 57 mm -H exit port' Figure 2.8. C-Channel RTM mold. bottom aluminum 2.2 mm plate mold, which is shown in Figure 2.8. The external mold ring was then placed on top of the fabric and carefully pushed over the lower mold to create a C shape. The glass top plate was then placed on top and clamped down using twelve C-clamps torqued to 17 cm-kg. This mold was then injected identically to the large flat plates previously described. The two C-channel exterior web faces were lightly sanded with 180 grit emery cloth and wiped clean with a sponge and water. After air drying, the two C-channels were bonded together to form an !-section. The adhesive used exclusively during this I-beam study was Hysol EA 9309.2NA; it was cured using the manufacturers recommended procedures. Beams numbering 30 and higher involved an !-channel mold which is shown in Figure 2.9. This mold operated exactly as the C-channel mold, but eliminated sanding and the other intermediate steps involved with secondary bonding of the two C-channels; it produced an !-section with less dimensional variability. Previous dimensional variability was caused by surface sanding and a poorly controlled adhesive layer thickness. Table 2.5 summarizes the beams and the different !-shapes used. To this !-Section was added 2 2 additional shear and torsional stiffeners in the load reaction areas to prevent shear failures between loading points. These additional elements are summarized in Table 2.6. Flange material on this !-Section was manufactured using the large flat RTM mold, cut up into 54 mm by 760 mm flange test sections, lightly sanded on one side and bonded to the I- Section external flanges. Load pads were then attached to the flanges. These pads were necessary to provide a wear surface for fatigue and to distribute the loading. Surfaces which were bonded together were mechanically clamped using C-clamps and load transfer bars, while the adhesive cured over a 24 hour period at room temperature. The completed beam was then post cured at 60 °C for two hours. The load pads on the beam, shown in Figure 2.10, were then machined in a vertical milling machine so that they were perpendicular to the web and parallel to the flange plane. side plates bottom plate 2.9 mm Figure 2.9. Web !-section RTM mold. 23 Table 2.5 Summary of web I-shapes used in Beams 6 through 59. Beams Web lay-up Web database material Average thickness, mm Vp,% Web Flange2 Web Flange 6 -2 9 (±45)3 CHlO 5.3 (0.11)1 2.3 (0.14) 34 33 30 -33 (±45/0/±45)s CH3 5.5 (0.16) 2.1 (0.21) 30 31 34,35 (±45/0/±45)s CH12 3.0 (0.10) 1.6(0.19) 34 28 51 -59 (0/±45/0)s DD5 3.0 (0.13) 1.6 (0.13) 33 28 'Numbers shown in parenthesis are the sample standard deviation. 2 Flange portion of the web I-shape, not the total flange. 610 mm 381 mm >Load pads Compression f la n g e ^ Tension flange Shear stiffeners Torsional stiffeners Load pads Figure 2.10. Assembled I-beam. 24 Cylindrical Tubes The tapered cylindrical tubes were manufactured by placing the fabric around a two piece tapered steel mandrel, one ply at a time, with no circumferential overlap. The fabrics were held in place by tacking small areas of the fabric surface with 3M spray adhesive number 77. The 45° plies were placed on the mold individually, which required removing the stitching thread (de-coupling) from the ±45° fabrics. With the completed lay-up on the steel mandrel, this section was then placed in a two piece clam­ shell (external) mold. The ends of the mold were then sealed and filled with resin. After two hours, the mold clamping bolts and the internal mandrels were removed. After an additional four hours, the external mold was separated and the tube removed. This mold Table 2.6. Summary of additional beam components. Beam Component Lay-up Fabric Vf Thickness Drawing Shear stiffener (±45), DB400 0.40 8.5 mm h-------- 295 mm -------- i 56 15 mm radius^) I-------240 mm —— 4 Torsional Stiffener (±45)* DB400 0.40 8.5 mm ~E E S ------- 56 mm------ » Load Pad (±45),, DB400 0.42 16 mm 37 mm —4 / X l I h------- 82 mm ---------- 4 width = 54 mm 25 is shown in Figure 2.11. These tubes were then attached to structural load transfer ends, which allowed the tube to be tested. The details of these aluminum 2024-T3 ends are shown in Figure 2.12. The ends consisted of an internal plug which was inserted and attached to the tube end using Hysol BA 9309.2NA adhesive. The aluminum ends were prepared for bonding following the ASTM standard D2651 involving P-2 etchant, Turco 4215NC-LT alkaline cleaner and acetone. Prior to the bonding of the external ring, approximately ten meters of glass roving was impregnated with polyester and wrapped around the ends of the tubes to aid in filling the space between the tube outside diameter and the inside diameter of the external ring. After curing the polyester, the external ring was attached and the void space filled with the Hysol adhesive. The entire assembly was then post cured at 60 °C for two hours. The finished assembly is shown in Figure 2.13. Fiber Volume Fraction (Vf) Determination In all the composites, the percentage of glass reinforcement was determined by the matrix burn off method described in ASTM D2584. This process involved taking a known volume of composite material and placing it in an electric muffle furnace at a temperature of 550 0C for one hour or until all of the carbon on the glass fibers had been removed. This glass reinforcement was then weighed on a Ohaus 1500 D digital balance with a resolution of 0.01 grams or a Sartorius BP210S digital balance with a resolution of 0.0001 g. The glass volume was calculated by dividing the glass fiber mass by a confirmed glass density of 2.56 g/cm3. This glass volume divided by the original volume / equaled the fiber volume fraction. The only deviation from the ASTM standard was the 26 ex terna l mold "— 25 mm 4 4 mm _L --------- 3 0 5 mm --------------- tub e th ick n ess = 3.1 mm end cap Figure 2 .11. Cylindrical tube RTM mold. Internal end External ring 89 mm diameter bolt circle 6 -13 mm diameter holes 60 degrees apart Top v iew Top v iew i-34 mm-j 38 mm diameter (end of taper)^ 6 mm radius 13 mm 4 I- 13 mm 51 mm S id e v iew L— 56 mm— ►] 6 mm radius I : : I . I : I k—49 mm —*| S id e v iew WO) Co I I SL. _ t Figure 2.12. Aluminum 2024-T3 tube end fittings. 27 amount of material to be used in the burn off test. The standard requires five grams of material which works well with uniform, thin plied prepreg materials, but it was felt that the ASTM standard would not generate a representative average fiber volume fraction due to the coarse architecture, size and spacing of the fiber bundles in the stitched fabrics. Thus, a greater amount of material, 15 to 25 grams, was used. This fiber volume fraction was associated with the average thickness of the burn off specimen. If there was a difference between this thickness and the average thickness of the tested coupons, a linear Figure 2.13. Tube testing assembly. 28 (0/t45Z0) - D155, DB120 ,(t4 5 /0 /t4 5 ) - D 155, DB240 (M 5 /0 /t4 5 ) - D 155, DB120 3 0 — ( 0 ) . - D l55 — C om posite material th ick n e ss , mm Figure 2.14. Fiber volume content versus RTM composite thickness. adjustment to the fiber volume fraction was made and recorded. Figure 2.14 shows the fiber volume content versus thickness for different lay-ups studied. Generally, the Vf varied only by I - 2% between the average thickness of the burn off specimen and the tested coupons. Quantitative microscopy using Jandel Scientific Incorporated, Sigma ScanPro software was also used to determine the fiber volume content and porosity of smaller cross sections. 29 CHAPTER 3 MECHANICAL TESTING EQUIPMENT The static, fatigue and four point bending tests were performed on nine different testing machines listed in Table 3.1. The Fiber Testing Apparatus used a unique audio speaker as an actuator and an Instron 8500 electronic console to provide control and feedback. Approximately 80 percent of the tests were performed on the Instron 8501, five percent on the MTS 880 with the remainder of the tests on the other machines. The MTS 440 structural testing system has interchangeable actuators which were used in cantilever fatigue tests of the cylindrical tube sections. All the hydraulic machines utilized 21 kPa hydraulic pressures. The testing machines had their respective transducers: load cell, extensometer and actuator LVDT, calibrated to their respective ASTM standards. Load Cells The load cells in each of the mechanical testing machines, along with their associated readout electronics, were calibrated as a complete system following the standards in ASTM E4 and E74. These procedures were also used for additional piggy back load cells used with lower force tests. These ASTM standards allow a maximum of ±1 percent error. The Instron 8501, 8562, 8511 MTS 440 and 880 had maximum errors less than ±0.4 percent during the entire duration of this study. The load cells were 30 Table 3 .1. Summary of mechanical testing equipment. Machine Actuator control Capacity Stroke Servo valve capacity Instron 1350 Servo hydraulic 98 kN ±51 mm 0.32 L/s Instron 8562 Servo electric 100 kN ±51 mm Instron 8501 Servo hydraulic 100 kN ±51 mm 0.64 L/s Instron 8511 Servo hydraulic IOkN ±25 mm 0.32 L/s Instron 8872 Servo hydraulic 20 kN ±51 mm 0.64 L/s MTS 440 Servo hydraulic 50, 100 kN ±75, ±127 mm 0.64, 0.96 L/s MTS 440A1 Servo hydraulic 50 kN ±267 1.92 L/s MTS 8802 Servo hydraulic 250 kN ±140 mm 0.64 L/s Fiber Testing Apparatus electric ION ±3 mm 22 N ±4 mm 1 - The original 406 test controller was replaced with a new digital 407 controller 2 - The original 880 controller was retrofitted with Instron 8500 Plus electronics calibrated or verified every four to six months using standard calibration cells calibrated through Morehouse Instrument Company and by additional ASTM E617 Class I precision dead weights, calibrated directly against secondary national standards. The dead weights were necessary to calibrate the load cells in the zero to two kN range where the extensometers were used to measure the initial elastic modulus of the test coupons; they consisted of ten separate 44.48 N weights. The standard test weights were not corrected for gravimetric differences between the standards calibration laboratory and the testing machine locations, as this effect was considered negligible. Smaller, NIST (National Institute of Standards and Technology) traceable weights under 10N, were also employed to calibrate equipment which operated in these lower ranges. The load cells used in the testing machines are listed in Table 3.2. 31 Table 3.2. Summary of Load cells. Machine Load Cell Capacity Manufacturer Serial Number Instron 1350 100 kN Lebow 3 116-136, sn 2 133 Instron 8501 IOOkN Instron, sn UK515 Instron 8511 22 kN Sensotec, sn 336154 Instron 8562 100 kN Instron, sn UK 517 Instron 8872 25 kN 2527-101,sn 10787 MTS 440 45 kN MTS 661.21, sn 442 100 kN MTS 661.21, sn 585 250 kN MTS 661.22, sn 461 MTS 880 250 kN MTS 380041-04, sn 69 General Use (Piggy back) 2.2 kN. Lebow 3132, sn 8796 LI kN Interface 1010AJ-250-B, sn 103726A Fiber Testing Apparatus 4.45 N Omega Engineering Inc. LCL-454G, 981077894 9.8 N Omega Engineering Inc. LCFA-1 KG, 970805 22.2 N Omega Engineering Inc. LCL-005, 05993101-016 Extensometers Contact extensometers and their associated electronics were directly calibrated and verified to ASTM E 83 and classified as class B2 extensometers with a maximum error of ± 0.5 percent. The seven extensometers used during this study are summarized below in Table 3.3. The extensometers were calibrated using a Boeckeler Instruments mechanical micrometer model 4-MBR which had a resolution of 0.0005 mm (0.5 pm) and a certified maximum error of 0.00033 mm (0.33 pm). A Mitutoyo IDC - 112E digital gage with a resolution of 0.001 mm was also used. The gage length was measured with an optical microscope calibrated with a Nikon MBMl 1100 objective micrometer. 32 Table 3.3. Summary of extensometers. Extensometer S/N Range Gage Length Machine 2620-524 6236 ± 5 mm 12.70 mm Instron 1350 2620-525 6237 ± 5 mm 12.70 mm Instron 8501 2620-528 8405 ± 5 mm 12.70 mm Instron 8501 2620-824 185 ± 5 mm 12.70 mm Instron 8501 2620-826 251 ± 2.5 mm 12.70 mm Instron 8501 2620-528 8405 ± 1.3 mm 12.70 mm Instron 8511 632.12B-20 430 + 13/-2.5 mm 25.40 mm MTS 880 The gage lengths of the extensometers were checked with this digital gage and an optical microscope as described in ASTM E 83 using the indirect method. During tensile strain measurements, the extensometer was attached to the edge of the test coupon, or when possible, on the face of the coupon using rubber bands. When placed on the face of the coupon, it was necessary to attach two pieces of self adhering 240 grit polishing paper (extensometer mounts) to prevent the knife blades from slipping and to prevent the blades from damaging the composite surface. The knife blades were sharpened or replaced when they were damaged or failed to track the composite surface strain. Generally, the extensometer was removed prior to catastrophic failure of the test specimen to prevent damage to the device. The extensometer was not used during compression tests due to the short gage length of the compression coupon and the possibility of extensometer damage, so strain gages were generally used instead. Actuator Position (LVDT) The actuator position was calibrated using a CD IJ4-C100-5000 mechanical 33 displacement gage with a resolution of 0.0254 mm (0.001 inches). Gage blocks were used to check displacements and set compression gage lengths (12.70 mm). The gage blocks were of grade A+ or better. Although no ASTM standard was referenced for this procedure, the maximum amount of error was less than ±1 percent over the entire actuator travel range. Strain Gages A Measurements Group Incorporated 2100 system strain gage conditioner and amplifier system with eight strain channels was used to measure strains. The strain gages were calibrated using the internal shunt calibration of the 2100 system. This active gage method of calibration and operation used a three lead wire circuit as recommended by Measurements Group TT-612 technical bulletin and conformed to ASTM E251. A minimum wire gage of 26 was used for connecting the gages to the instrumentation and the total length of connection wire was minimized to reduce lead wire resistance effects, hi all cases, the excitation voltage was 2.000 Vdc with 120 and 350 ohm strain gages. Electronic gain's of approximately 500 were used for strains up to 13.6 percent and gains of 5000 allowed measurement of strains up to 1.36 percent. Generally, one quarter Wheatstone bridges were used for strain measurements. The strain gages used in this study are summarized in Table 3.4. In all cases, the life of the strain gage was limited to a few hundred cycles, as matrix cracks on the surface of the composite opened and damaged the strain gage, as shown in Figure 3-1 from Beam 29. 34 Table 3.4. Summary of strain gages. Company Catalog Number BLH FAE-25-35-S13EL1 FAET-2S A-3S-S13 P A -7 Micro-Measurements CEA-00-250UW-3501 EA-OO-015EH-350 EA-06-250-BF-350 ED-DY-125 AD-350 WA-OO-015-EH-350 WK-06-250AF-350 WK-00-250-BG-350 1 - These gages had the longest lifetimes underlying matrix cracks ,cutting strain gage foilt T ^strain gage foil Figure 3 .1. Strain gage photograph showing tensile strain cracks. 35 Using extensometers on the fatigue coupon for extended periods caused damage and subsequent failure of the coupon, as the knife edges of the extensometer dug into the coupon. Thus measurement problems were addressed with the development of strain clips which are shown in Figure 3.2. These devices reduced the running strain that the strain gage experienced, which prevented fatigue failure of the gage and eliminated strain gage failure by matrix cracking. Of the many methods tried to measure the fatigue running strain of the composites, this method yielded the best results. The clip gage was manufactured from 0.15 mm brass (C26000) shim stock, using a one half Wheatstone strain gage bridge with temperature compensation which minimized any material thermal mismatch and produced a durable gage. An additional aspect associated with this gage was that it initially had to be calibrated on each specimen with an extensometer or another strain gage on the composite surface. Adhesives used to bond the strain gages to the composite surface included Loctite 496 cyanoacrylate ester and Micro-Measurements Incorporated M - Bond AE 15 epoxy resin. The AE 15 was used when the expected strains were greater than two percent. Testing Machine Load Train Alignment Alignment of the load train of the mechanical testing machines was critical to ensure a uniform stress distribution across the test coupon, especially during compression tests. The grip and actuator travel centerline was adjusted to conform to ASTM E3039 even though the main standard concerning alignment is detailed in ASTM E1012. ASTM E1012 does not address the acceptable amount of bending in a testing setup, whereas 36 tension compression Figure 3.2. Clip strain gage. ASTM D 3039 addresses it as an additional aspect to composite testing. Table 3.5 summarizes the available standards and their recommended allowable bending strains. The amount of bending during an axial test must be minimized, but it cannot be totally eliminated, so every effort was made to limit the amount of bending strain to less than five percent of the axial strain. The load train alignment had to be checked every time the hydraulic grips were removed from the machine or just prior to compression testing. Table 3.5. Summary of applicable bending standards for uniaxial testing machines. Standard Maximum allowed bending strain (% of axial strain) ASTME 1012 Not stated ASTM D 3039 5% General Electric S-400 10% for ductile materials 5% for brittle Military Standard 1312B 6% 37 To measure the amount of bending, four strain gages were placed on a thin (3 mm) rectangular, 4130 steel, coupon, as per ASTM D3039. The 3 mm thick by 50 mm wide steel calibration coupon was chosen as it was similar in dimensions to the fiberglass coupons. Although aluminum could yield higher sensitivity, gripping indentation by the steel grip faces could influence the results. The coupon was loaded up to a calibration load of 53 kN and the maximum amount of bending was calculated using the equation in Section 10 of ASTM D 3039. This maximum load, 53 kN, was used to prevent yielding of the calibration coupon. If the amount of bending strain was greater than five percent of the axial strain, the load train of the testing machine was adjusted. This alignment procedure was performed with the actuator at the position it was to be used during the material test to ensure test alignment. The hydraulic wedge grip faces were cleaned and freshly coated with MolyKote molybdenum disulfide lubricant between the grip body and the grip faces. Required cleaning of the grip faces was necessary as the fatigue tests wore down the lubricant and produced a hard black film between the grip face and the grip body. This film, if not cleaned and replaced regularly, caused angularity of the grip faces and nonuniform grip pressures and, therefore, grip misalignment. Fiber Testing Apparatus Standard testing machines are limited in their frequency and displacement response by low force noise and hydraulic oil pumping requirements. Testing to high cycles requires high frequencies to be practical, and high frequencies can only be used for very thin specimens to avoid hysteretic heating. In order to test a very small tow of 45 38 glass fibers to one billion cycles (or more), it was necessary to build a separate testing apparatus. The required maximum load was less than 15 N, and the desired frequency was 200 to 300 Hz (or higher). The Instron 8511 was used to test the D155 tows to IO8 to IO9 cycles, but the maximum acceptable frequency was judged to be only 80 Hz, and one test required 97 days. A new apparatus was constructed using a standard 25 cm diameter audio speaker (Radio Shack 40-1028) as the actuator. A second apparatus using a 30 cm diameter speaker (Radio Shack 40-1029) was later constructed. A grip for load transfer to the coupon was constructed out of carbon fiber to minimize the grip mass (18 g with bolts). The test coupon was gripped in a sandwich friction grip system where two bolts clamped the grip assembly around the coupon. Self adhesive 1000 grit polishing paper lined the internal surface of the grip plates to ensure coupon gripping with the low clamping pressures generated by the 2 mm diameter clamping bolts. This low clamping pressure also minimized any clamping damage to the coupon. This grip assembly was then bonded to both the speaker dome and the cone with Plexus A0425 adhesive. The upper grip assembly was bolted to a bending beam load cell, which completed the load transfer path. This testing apparatus is shown in Figure 3.3 • along with the coupon geometry. The crosshead was moveable by two 6 mm bolts, which were used to apply the mean cyclic load to the test coupon. An Instron 8500 electronic display tower was used to condition the load cell. The display also provided a sine wave frequency and cycle counting for the test. The Instron electronics were only capable of providing a low power frequency output up to 200 Hz, which was used as an audio input to an 80 watt amplifier to power the speaker. For frequencies greater than 200 Hz, a separate frequency generator was used. 39 Crosshead Load cell Grips Test coupon assembly I 25 mmr 1 25 cm diameter speaker Acoustical foam Cyanoacrylate (Quick Gel) Paper tabs |25 mm^ l Figure 3.3. High frequency strand testing apparatus and test coupon geometry. Impregnated1 strand Silicone adhesive 40 CHAPTER 4 TESTING AND TEST DEVELOPMENT Coupon Tests Unless noted, all fatigue tests were run at constant load amplitude with a sine waveform. Individual test coupons were selected from all available test coupons using a simple random sampling without replacement scheme, for static and fatigue tests at the different R values. The fatigue test R value is calculated by: R Value Minimum cyclic stress Maximum cyclic stress (4.1) The three most common R values used in this study were: R = 0.L 10 and - I. The relationships of stress, or strain, versus time for a sine waveform for these R values are shown in Figure 4.1. When additional test coupons were needed from two or more material plates, every effort was made to randomly select coupons from all the different material plates prior to initial testing to ensure a random selection from all the possible test material. For all the tensile tests, static and fatigue, an initial material elastic modulus, E, was calculated by taking the least squares fit of at least five evenly spaced axial stress-strain data points at total strains less than approximately 0.12 percent. This procedure allowed for modulus calculations with little, if any matrix cracking and to 41 ensure no extensometer slippage. The extensometer was used to obtain the initial fatigue running strain of the coupon and then removed to prevent damage to the test coupon. Compression tests utilized strain gages for the static tests and the fatigue tests used the average material modulus to calculate the fatigue running strains. 2 0.8 R = 0.1, Tension - Tension 5 0.4 R = -I, Tension - Compression R=IO, Compression - Compression Figure 4 .1. Constant stress amplitude sine waveforms for different R values. Tensile Tests A minimum of three static tensile tests were performed for each material, with the testing machine under displacement control, using a linear displacement - time ramp rate of 13 mm per second. This ramp rate provided similar strain rates to the fatigue tests. Figure 4.2 shows typical stress-strain diagrams for material DD5P for different testing rates. Figure 4.3 shows the trend of ultimate tensile strength versus the testing 42 displacement rate. The testing rate does significantly influence the static tensile ultimate strength, but does not significantly alter the elastic modulus over the strain rate range of 2.5x10"5 to 1.27 x IO"1. The effect of coupon width was also studied and is shown in Figure 4.4. As long as the coupon width has a representative number of fiber bundles to minimize the effects of edge bundles, thicknesses greater than approximately 20 mm showed little sensitivity in ultimate tensile strength. 12.7 mm/s 2.5 mm/s 0.25 mm/s w 6 0 0 0.025 mm/s to 5 0 0 m 3 0 0 1 .5 2 .0 Tensile strain, % Figure 4.2. Stress-strain curves for material DD5P at different testing rates. Most of the tensile tests were performed without computer data acquisition and relied upon the testing machine instrumentation to accurately record the maximum load applied to the test coupon. This method was periodically checked with an HP 5452A 500 MHz digital oscilloscope with no noticeable problems. With the ultimate tensile strength calculated, the first fatigue test was then run at approximately 60 percent of the static 43 1 6 0 0 „1400 CL ^-1200 # 51000 ■B ^ 800 il)I 600 I 400 =) 200 0 1E-3 1E-2 1E-1 1EO 1E1 1E2 1E3 Displacement rate of static test, mm/s Material Lay-up VF,%Linear regression equation D155G [01,6 60 UTS= 1021 +68(rate) DD5P [0/+45/0] s 36 UTS = 741 + 68(rate) CH12 [±45/0/+45]s 34 UTS= 399 +32(rate) CH5 [(±45)3]s 28 UTS= 129 + 5(rate) - H -H B - H— HHH D155G ' DD5P ; CHl 2 CH5 — I— HH-H Figure 4.3. Tensile strength versus testing displacement rate (25 mm wide coupons with a 100 mm gage length). 900 800 I 700 I 600 I5000 V) 400 c 0) Z 300 fa 1 200 3 100 0 0 10 20 30 40 50 60 Coupon width, mm Database material description: a AA ▼ AA2 ffl CH12 ■ DD5P Figure 4.4. Tensile strength versus coupon width (100 mm gage length, 13 mm/s testing rate). ■ ■ ■ I A A A A A A A A- ▼ ▼ m FH FH ffl EB 44 strength, usually at an R value of 0.1. This fatigue data point was then used to approximate the fatigue sensitivity coefficient b from the linear semi-log relationship [2] - b Log N (4.2) where S is the maximum stress, S0 is the single cycle strength and N is the total cycles to failure. This equation was used to determine all stress levels of an S-N data set. Stresses were picked to obtain fatigue failures in each log decade (2, 3, 4,5,6 and 7) of the fatigue semi-log plot to accurately determine the fatigue trend. Test coupons were then randomly assigned to these stress levels, with a minimum of three coupons per stress level. These coupons were then tested in their assigned order. Most materials were tested to beyond IO5 cycles, with some more fatigue resistant materials tested to the IO6 to IO8 cycle range. Fatigue tests used a sine-wave cyclic waveform with the testing machine under load control, with active amplitude control, which increased the internal gain of the machine as the coupon compliance changed during the testing. The frequency of the waveform was varied approximately inversely with the maximum stress level, which maintains an approximate constant load rate. This limits the hysteretic heating within the coupon at higher loads and prevents thermal failures. The frequency was varied between I and 20 Hz in most cases. All the test coupons were ambient air cooled with an air flow velocity of approximately two meters per second measured one cm away from the coupon surface. This limited the maximum coupon surface temperatures to less than 5 0C above ambient room temperature. Surface temperatures of the composite were monitored 45 throughout the test using a Omega Engineering Incorporated HH23 digital thermometer with a Cole-Parmer E-08533-96 fast response thermocouple, with a time constant of 0.1 seconds. All the tests were performed at ambient room temperatures, 15 to 27 0C, and at low relative humidities, 10 - 50%, unless otherwise indicated. Generally, the test coupons were not removed from the hydraulic grips once the fatigue test was started. Occasionally, tests were stopped and the test coupon removed for examination. The coupons were then placed back in the grips and testing continued. Fatigue tests were generally performed until coupon failure, which was defined as the inability of the coupon to sustain the applied fatigue loading. Some of the tests were stopped before coupon failure (and after a large number of cycles) due to testing and time constraints. These coupons were labeled as “run outs”. With the completed fatigue diagram, the fatigue sensitivity coefficient b was then calculated using a least squares fit of the data points an a linear stress versus log cycles to failure plot, assuming equation (4.1). The goodness of fit coefficient of the least squares fit was generally greater than 0.96. This testing procedure was then repeated for different R values (R = 10, -I). Tensile Test Development Most of the test development involving the tensile coupons was done in redefining a suitable geometry which minimized mechanical grip induced failures and produced fatigue failures in the gage length. Geometries different than the flat rectangular coupons with tapered tabs in the gripping areas, as described in ASTM D3039 and shown in Figure 4.5, were studied. It should be noted that ASTM D3039 was changed in 1993 to 46 allow the optional use of coupon tabs, which was done so that the test standard would be technically equivalent to the European ISO 527 standard. This process was necessary, as the initial number of grip induced failures (using the earlier coupon geometry), was quite high, which is a common testing problem [22 to 25]. It is unlikely that a universal test coupon geometry could be developed which would work for all the composite lay-ups; therefore, it was necessary to design specific test geometries for different lay-ups. Gage length plus 2X coupon width 38 mm 38 mm min. Top view Side view> 5 deg. Figure 4.5. ASTM D3039 tensile test coupon geometry. The highest percentage of grip failures involved the unidirectional, 100% O0 fabric, materials. The best testing geometry found for these materials involved tapering the thickness of the coupon by at least 40 percent. When tested, the thickness tapered coupon did start to delaminate at the shoulder, tending to create a rectangular cross section, but the delaminations stopped at the point where the coupon was clamped in the hydraulic grips. This method of thickness tapering was similar to placing additional tab material on the rectangular ASTM D3039 coupon, but during initial fatigue experiments with tabs, tab failures occurred, as the adhesives used to bond the tabs onto the coupon 47 failed. This type of failure did not occur with the thickness tapered coupons. It was assumed that slight thickness-direction (Z direction) waviness in the glass fabrics created some additional through-the-thickness reinforcement, and thus more shear resistance as compared with bonded tabs. Adams and Finley [26] labeled these cracks “thickness taper release cracks” in compressive coupons and believed that these cracks reduce the stress concentrations associated with the taper radius and gripping effects. It is assumed that this same beneficial effect occurs in the tensile coupon geometries tested in this study. Thickness tapering only worked for unidirectional materials. For materials with additional ply orientations, a width taper, resulting in a cross sectional area reduction of approximately 40 percent, or more, proved acceptable and minimized the number of grip failures. Careful width selection ensured that a representative volume of material was present in the gage section. This geometry still had grip failures, especially with high percentages of zero fibers in the load direction and fiber volume fractions greater than 0.35. Most of the coupons with grip failures did have other damage nucleation sites all over the gage length before final failure. Width tapered coupons did split at the shoulders, which tended to create a rectangular coupon. The shoulder cracks stopped in the compressive zone created by the gripping force, similar to the thickness tapered coupons. The coupons developed cracks and delamination during the first few hundred cycles ■ which initiated in the taper radius region of the coupon and propagated along the coupon length and arrested in the compressive zone produced by the clamping action of the wedge grips shown in Figure 4.6. Coupons of the width tapered geometry were tried with and without additional tabs with no noticeable difference in the number of grip failures or 48 the number of fatigue cycles to failure. In fact, the presence of a tab produced no beneficial effect on the grip induced damage in the composites with fatigue lifetimes less than approximately a million cycles. It has also been reported that some material coupons without tabs provide consistently better testing results than those with tabs [22]. This gripping damage is also illustrated in Figures 4.7 and 4.8. The tab material, however, did provide abrasive protection to the test coupon on higher cycle (> I million) fatigue tests. Composite coupons with 50 or less percent 0° material did not generally need any special machining or tabs. These coupons had very few grip failures and the flat rectangular geometry proved acceptable. Figure 4.6. Width tapered coupon (DD5P material) with shoulder splitting. Test Coupon Gripping Hydraulically operated wedge grips were used to clamp the test coupons into the axial load train of the testing machines using externally generated and controlled hydraulic pressure. A tensile or compressive stress was applied to the coupon through a (. mechanical shear interface over the clamped coupon ends. The clamping force on the coupon is directly proportional to the applied hydraulic pressure, as shown in Figure 4.9. The hydraulic pressure caused the grip body to move down, causing the wedge grips to close and clamp onto the test coupon. The hydraulic pressure in the grips was also dependant upon the applied tensile load being transferred through the test coupon. Due to the hydraulic grip design, the hydraulic fluid pressure caused any axial load transmitted through the test coupon to be transmitted through the hydraulically prestressed grip body. When the load transferred through the test coupon was greater than the load induced by the hydraulic grip prestress, the hydraulic pressure in the grip body increased as the fluid started to transfer more load, as shown in Figure 4.10. This Figure shows three different initial grip hydraulic pressures which, as the axial tensile load on the test coupon was 49 Figure 4.7. Grip damage in test coupons, with and without tabs. 50 Tab surface A DD5P material under tab positive image negative image B C Z Damage area Bundle pullout Figure 4.8. Tensile fatigue damage present under tab material. Test Coupon •Grip Wedges /Grip Body Hydraulic Pressure Actuator Figure 4.9. Instron hydraulic wedge grip cross section. 51 increased, remained constant until the prestress was not enough to handle the transmitted axial load causing the internal hydraulic pressure to increase. This increase in hydraulic pressure causes an increase in the test coupon clamping force, which is shown in Figure 4 .11. This force divided by the composite gripped area determined the average compressive stress in the through-thickness direction (Z axis) of the test coupon in the grip area. Figure 4 .11 was used to determine the correct hydraulic gripping pressure for the fatigue tests. This data was obtained with an Omega Engineering Incorporated PX602 pressure transducer and DP41S digital meter. In s tron 8 5 0 1 Max. axial load on the coupon = 4.1 X (hydraulic grip pressure) Applied tensile load through the test coupon, RN Figure 4.10. Applied axial load to the test coupon versus the grip body hydraulic pressure. 52 Instron 8501 S C §.3 8 CO CD2 £O) .E O- Eroo Q- 120 110 100 9 0 8 0 7 0 6 0 5 0 4 0 3 0 20 10 0 z Z X X X ^ — — x X Grip clamping force on t ie cou]Don = I .18 (Applied axial IDad) Compressive stress on coupon = [ 1.18( Applied axial load)] X — — — gripping area or coupon --------1--------1--------1-------- 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 1 0 0 1 1 0 120 Applied tensile load through the test coupon, RN Figure 4 .11. Applied axial tensile load versus the hydraulic grip clamping force on the test coupon. The gripping force was measured with a 6.350 mm thick Mitutoyo steel gage block with a full strain gage bridge attached to its surface and the Measurements Group Incorporated 2100 system strain gage conditioner. Under cyclic fatigue loading, if the initial grip hydraulic pressure was insufficient to apply the correct amount of prestress to the grip body, the increasing and decreasing hydraulic grip pressure caused the corresponding coupon clamping force to increase and decrease. This varying clamping force caused the steel wedge grips to bed-down and abrade the tab surface which caused premature failure of the coupon. When the grip hydraulic pressure was too high, the excessive clamping force also caused a premature coupon failure due to the increased stress concentration at the grip edge. This clamping- 53 force-hydraulic pressure interaction did not occur during pure compression tests. Due to the design of the hydraulic grips, compressive loads were transferred directly into the steel load train structure and actuator. The hydraulic pressure just secured and clamped the test coupon in place. With the correct grip clamping pressure, the tensile coupon failures shown in Figures 4.6, 4.7 and 4.8 still occurred. It was suspected that the steel grip faces were not applying a uniform gripping pressure to the test coupon. The pressure distribution of the grip faces was checked using Pressurex tactile pressure measuring film manufactured by Fuji Photo Film Company Limited. The film is shown at four different clamping pressures on a 4.7 mm thick by 50 mm wide steel specimen (machinist’s precision flat and parallel) in Figure 4.12. The color contact film revealed a grip face clamping area at the top of the steel wedge faces which had no contact pressure on the coupon. The rest of the grip face had a uniform pressure distribution over the test coupon clamped areas. This steel grip face wear zone at the top of the faces was the result of long term fiberglass test Grip wedge face contact area with coupon vs. hydraulic pressure Grip hydraulic pressures 3.4 kPa 6.9 kPa 10.3 kPa 13.8 kPa Figure 4.12. Steel wedge grip face contact area with the test coupon. Shown by pressure film. 54 coupon movement, and corresponding wear in this area. Fatigue tests were then performed with the test coupons clamped in the grip areas with no noticeable wear under a uniform pressure distribution, with the same fiberglass gripping damage as before. This damage area in the fiberglass test coupon must have been caused by active movement of the fiberglass over the steel grip face. This active movement is probably the result of a Poisson’s ratio thickness shrinkage effect under axial loading, shear load transfer effects and material stiffness mismatch, but the reason this wear zone on the steel grip face is not symmetric is still unclear. Compressive Test Development Compressive testing of materials is always a difficult and controversial process as premature failure, or buckling of the coupon can undermine the test. Presently, ASTM specifies only three different methods of axial compression testing under ASTM D3410, while approximately 17 other methods are also used [27], and each method has been shown to produce different results. All these methods represent an attempt to obtain representative compression properties of the material being tested while limiting the amount of buckling. Buckling can be prevented by continuously supporting the faces of the test coupon and having the gage length as short as possible. Continuous support is not very practical in fatigue tests, as the supports cause abrasive damage to the coupon. Exploratory tests at the beginning of this study led to the choice of an unsupported gage length of 12.7 mm, which has given results consistent with compression failures in composite beam flanges (discussed later). This gage length is also required by the DTRI 55 (Illinois Institute Technology Research Institute, ASTM D3410), Celanese (ASTM D3410) and Wyoming modified Celanese compression test procedures. The tendency of a compression coupon to exhibit buckling is indicated by its slenderness ratio. With a 12.7 mm gage length, and a rectangular cross section, the column slenderness ratio is calculated by [28] , \/l2 Lf Slenderness ratio = --------- 4.3 t where Le is the effective length of the test coupon, which, for fixed-fixed end conditions is equal to 12.7 mm x 0.5 = 6.35 mm, and t is the composite thickness in the gage length. A study by Adams and Lewis [29] indicated that a slenderness ratio less than 30 was not prone to cause buckling failure in glass epoxy unidirectional composites. A 12.7 mm gage length and a slenderness ratio of 30 limited acceptable compressive testing, according to the above criteria, to test coupons which had a thickness greater than 1.5 mm. The initial compression tests performed on the Instron 8501 provided very low ultimate compressive stress values as the actuator moved sideways under the side loads produced by the coupon during testing, causing premature buckling failure due to eccentric compressive loading. This side movement of the actuator was due to the Instron 8501 actuator top hydrostatic bearing, whereas previous compression tests were performed on the MTS 880 which had both upper and lower labyrinth bearings which prevented this sideways translation. Figure 4.13 shows the applied lateral force vs. the lateral deflection of the hydraulic grip head. The translation of the Instron 8501 grip was 56 corrected by placing two needle bearings connected to the machine frame, on either side of the grip head, as shown in Figure 4.14. This assembly acted as a linear bearing guide for the grip and prevented the sideways translation of the grip head during compression. Figure 4.14 also shows the grip anti-rotation device which prevented the lower grip and actuator from rotating and causing premature coupon failure due to additional torsion loads. Where necessary, strain gages were attached to both the front and back center surfaces of the compressive coupon for stress-strain measurements. The extensometer could not be used due the small gage length of the test coupon and the possibility of extensometer damage during the test. Using back-to-back strain gages on the compression coupon provided valuable information on any bending or buckling during the test, which is shown in Figure 4.15. This figure indicates that a perfect compression test would show no bifurcation, or separation of the stress-strain curves provided by the two strain gages. If bifurcation of the curve is present, it indicates the presence of bending, buckling or a combination of both, which would effect the validity of the results. The effect of compressive strain rate was also studied and is summarized in Figure 4.16. The rate effects are similar to those of the tensile coupons in Figure 4.3. Figure 4.17 shows the effects of coupon width on the compressive strength and shows similar behavior to that observed in the tensile tests. Again, as long as there was a representative number of complete fiber bundles in the gage length, as compared with the number of partial bundles on the edges, the compressive strength was insensitive to widths greater than approximately 20 mm. 57 1000 900 800 2 L 700 0 600 (D 3 5 0 0 1 4 0 0 g 3 00 200 100 0 0 0.1 0 .2 0 .3 0 .4 0 .5 0 .6 0 .7 0 .8 0 .9 1 Grip face sideways translation, mm Figure 4.13. Hydraulic grip head translation versus side loading force. . I I T I / / With ou t c(Dnstramt Slope = i io k l \ | /m m Slope = 11 )2 N/mr / Upper spherical ended support (both sides) Lower bearing ended support (both sides) Actuator anti - rotational support Figure 4.14. Anti-translation and anti-rotation devices. 58 Perfect test Strain Buckling Strain Bending Strain Figure 4.15. Typical compressive stress-strain curves with back-to-back strain gages. 1200 TO 1100 5 1000 t 900 S 800 ! 700 1 000 2 500I 400 v 300I 200 3 100 0 IE -3 1E-2 IE-1 1EO 1E1 1E2 1E3 Speed of static test, mm/s Material Lay-up vF,%Linear regression equation D155G [0],6 60 UCS = 711 +49(rate) DD5P [0/+45/0] s 36 UCS = 604 + 98(rate) CH12 [±45/0/+45]s 34 UCS = 443 + 5(rate) CHS [(±45),ls 28 UCS = 215+ Iterate) D155G DD5P I * * CH12 I ----1- CH5 i— I I M I I I -------1— I—fr-H m ----- 1— t H-H Il l l -------1— I- H-I H ll ------1— I -H Figure 4.16. Material compressive strength versus testing displacement rate (25 mm wide test coupons with a 13 mm gage length). 59 800 ro 1 700 § ,600 g "S 500 a> % 400 2 E 300 8 S 200 *I I 100 0 0 10 20 30 40 50 60 Coupon width, mm Database material description: ▲ AA ▼ AA2 m CH12 ■ DD5P Figure 4.17. Apparent compressive strength versus coupon width (13 mm gage length with a 13 mm/s testing rate). ■ ■ ■ ► B ► $ A ffl __X EB $ _ ▼ ▼ ▼ I ▲ ▲ I - Beam 4 Point Bending Development In order to perform the four point bending tests on the I-beams, the hydraulic grips of the Instron 8501 were removed and replaced with upper and lower two point loading platform which are shown in Figure 4.18. This assembly provided a more stable loading arrangement. The upper loading platform consisted of a W 150 x 18 (AISC W6 x 12) steel I-beam with two 50 mm loading rollers spaced 610 mm apart, center-to-center. These rollers used needle bearings to allow easy rotation of the loading rollers during the testing. Combs [21] initially discovered that these rollers greatly reduced the amount of axial loading being introduced into the composite beam which was generated from contact friction. The lower loading platform consisted of two load rollers spaced 381 mm 60 apart, center-to-center, on a 127 x 127 x 6.35 hollow steel box beam (AISC ST5 X 5 X 0.25). Both steel platforms conformed to ASTM A500, Grade B steel specifications. Additional stiffeners were required on the W 150 X 18 platform under the roller bearings to increase the lateral stability of the section. The loading platforms were centered on the load cell and actuator and bolted down. Four shear strain gages were initially placed on the steel I-beam to check for system alignment with the lower box beam and to ensure that half of the applied load was being transferred through each roller. Figure 4.18. I-beam four-point bending test set-up. The composite beam to be tested was placed in the four point loading apparatus under a pre-load of 100 N. This pre-load was used to ensure positive contact of all four load pads on the four rollers, for initial readings. With the beam centered on the loading Lower load platform 61 rollers, two longitudinal end constraints were adjusted to keep the composite beam from rolling off of the rollers. These supports allowed the beam to move only five mm longitudinally, and thus prevented the beam from slipping off of the load rollers. For lateral alignment, four aluminum supports, 4 mm x 10 mm, kept the composite beam centered, side-to-side, on the load rollers. These bars made contact with the shear stiffeners, outside of the loading areas. A Mitutoyo IDU25E digital indicator was placed in the center on the top tension flange of the I-beam to measure vertical displacement. Strain gages mounted in the longitudinal direction on the tension and compression flanges were connected to a Measurements Group Incorporated strain gage conditioner and zeroed at the 100 N preload. The beams were loaded up to 18 kN in 8 steps, and readings from the two strain gages, the digital gage and the Instron 8500 electronics were taken. The digital displacement gage was then removed and the fatigue or static test was continued. These initial measurements were done for all the beams to obtain an indication of initial beam stiffness properties. The static tests were performed with the Instron 8501 in displacement control at a constant rate of 0.05 mm per second, while fatigue tests were run under load control with active amplitude control. During higher cycle tests, the beams were periodically taken out of the test setup and inspected for damage. Flexural tests were performed until beam failure, which was defined as either the inability of the beam to withstand the absolute maximum applied load or else total flange delamination. Upon failure, displacement safety limits terminated the test. 62 Cylindrical Tube Bending Tests The first series of cylindrical tube tests were performed under 4-point bending in the same apparatus as used for the beams. The second series of tests loaded the tube as a cantilever beam which was more representative of an actual wind turbine blade in service. The setup is shown in Figure 4.19. The composite tube was mounted with aluminum end assemblies to transfer the loads through the tube. This assembly was fitted with a one meter long steel cantilever beam (free loading end), while the other end (fixed end) was bolted to a 127 x 127 x 6.35 HSS (AISC ST5 X 5 X 0.25) steel support, which in turn was bolted to a 30 cm thick structural floor with two 38 mm diameter bolts in the MSU Structures Testing Laboratory. The free end of the assembly was then loaded with a 45 RN MTS hydraulic actuator equipped with MTS 406 controllers. Fiberglass tube test section Steel cantilever beam Actuator Figure 4.19. Cylindrical tube cantilever beam testing set-up. 63 CHAPTER 5 COUPON TESTS The database includes a systematic variation in basic laminate parameters to establish basic trends in static and fatigue behavior. Ultimately, these tests are intended to identify materials with improved static and fatigue resistance. Over 6,000 static and fatigue tests were performed, covering ,148 different materials. The database grew to these proportions in response to significant and unexpected variations in fatigue resistance which required detailed systematic study. This chapter explores trends in static and fatigue resistance included in the database and attempts to identify the underlying mechanisms responsible for failure. Three levels of complexity are considered: simple unidirectional composites, unidirectional composites with stitched or woven reinforcing fabrics, and multidirectional laminates. Special attention is given to the high cycle behavior and basic mechanisms of breakdown in unidirectional materials. Unidirectional Materials Fiber Packing An ideal composite lamina would have all the glass fibers aligned straight and 64 parallel to each other and to the load path, with just enough spacing between the fibers to prevent fiber-to-fiber contact. For this to occur, the arrangement of fibers would be in a uniform geometry, such as a square or hexagonal array. If all fibers have the same diameter, these arrangements would have a theoretical maximum fiber volume fractions of 0.79 (square) and 0.91 (hexagonal), shown in Figure 5.1. Random packing arrangements have a maximum fiber volume fraction which is between these limits and has a value of approximately 0.82 [30]. Practically, the fibers will involve a range of diameters, 10 to 20 pm, which could increase these fractions slightly. Increasing the fiber volume fraction is advantageous, as it increases the primary properties: longitudinal elastic modulus and tensile strength of the lamina. Above a fiber volume fraction of approximately 0.70, the transverse properties of the composite will degrade, as fibers contact each Other and stress concentrations increase, which is detailed in Figure 5.2 [3,1, 32]. The stress concentrations around the fibers are higher when the fiber transverse modulus is higher relative to the matrix modulus. In a well bonded composite, a matrix material which would yield at a lower stress would decrease the local stress concentrations. Strand Deformations in Fabrics Glass fabrics are constructed using glass fiber strands or tows, which contain hundreds to thousands of continuous glass fibers, 10 to 20 pm in diameter, without any definite twisting of the fibers. These tows are stitched or woven together to form a fabric, which allows the fabric to be handled during composite manufacturing. Fiber handling 65 during fabric manufacturing significantly reduces the fiber strength, as shown later. The properties of the fibers can be further reduced by the stitching thread tightness, and the spacing of the stitching or weaving. The stitching pinches the tow and causes a slight curvature of the fibers on the outside of the glass strand as the diameter locally decreases This curvature of the fibers introduces a bending stress in the fibers at the stitch, but it is postulated that the major effect is that the stitch decreases the average distance between fibers and causes the number of fibers in virtual contact, in that area, to increase. Virtual contact it is meant that the fibers appear in contact in micrographs; whether a thin matrix layer is present between the fibers is not known. The reinforcing fabrics have bundles of glass fibers separated by an area without fibers which forms resin rich areas between the tows in stitched fabrics, and both above 0 .9 Q 0 .8 d) 0 .7c 1 06 % 05 ^ 0 .4 OJ 2 0 .3 g < 0.2 . D . I cfb O O O O d b O O O O O H \ N x \ O \ . X O X Squars Packing Hexagonal Padling \ Squaie - Hexa £onal 0 0 .2 5 0 .35 0 .4 5 0 .5 5 0 .65 0 .7 5 Fiber Volume Fraction Figure 5.1. Fiber volume fraction versus the average fiber spacing in a composite with theoretical square and hexagonal packing geometries. 6 6 % I 5 2.2 I I l £ 2 — Maximum Principal Stress Optical birefringence image (A. Puck, 1967) Z Z 1.2 'Data from DF Adams, D.R. Doner, "Transverse Normal Loading of a Unidirectional Composite", J. Composite Materials, 1967,1:152---------1----------- 1----------- 1----------- 1------------1----------- 0.4 0.6 0 Fiber Volume Fraction Figure 5.2. Fiber volume fraction versus the normalized maximum principal stress for a transversely loaded composite. and below weave crossover points in woven fabrics. It is the presence of this resin rich channel between the tows which reduces the overall fiber content, and hence the lamina properties. In order to increase the fiber content, the elliptical fiber bundle cross section must be compressed and forced to spread out across the width of the lamina to fill this channel. The stitching or weave crossover points inhibit this spreading out from occurring. Figure 5.3 shows three different magnifications of Material PP, which used 3M-SP250 prepreg (no stitching or weaving), compared with a unidirectional composite with D155 stitched fabric. The prepreg material shows a uniform distribution of fibers with no large resin rich regions; the D155 composite, because of the stitching, has large resin rich regions between the tows. Figure 5.4 shows the D155 confined tow area versus 67 the overall ply fiber content for materials DD6, DD2 and DD7. As the composite fiber content increases, the cross-sectional area of the individual tows decrease (as expected), squeezing out the excess resin. The D155 fabric tows in Figure 5.4 start to interact and fill the matrix rich regions in the adjacent plies, and thus the elliptical tow cross-section geometry deforms. If this deformation of the tow is not uniform along the length, where the tow enters and exits the resin channel in the adjacent ply, a rotation of the strand occurs. The figure shows that the fiber content inside the fiber bundle does not change as significantly as the average composite fiber content, and that the fiber content in the fiber bundle changes along its length (x-axis) due to the periodic presence of stitching. Figure 5.4 shows that the stitching causes up to a 10 percent local increase (from Vf = 0.58 to 0.68) in the fiber volume fraction of the strand contained within the stitching in the DD6 material; the DD7 material exhibited only a 2 percent increase (from Vf = 0.70 to 0.72). The determination of strand fiber contents at higher individual ply fiber contents was not performed due to the difficulty in determination of the boundaries between adjacent strands. Figure 5.5 shows the number of fibers in direct contact with adjacent fibers versus the ply fiber volume fraction, both within and between stitching threads. A large increase in the number of fibers in contact occurs in the 0.31 to 0.36 fiber volume fraction region, which also coincides with the region where most of the composites in the database start to decrease in fatigue resistance. It should be noted that the D155 tow has stitching every 4 to 6 mm, which means that the tow fiber content varies between a maximum and a minimum value every 4 to 6 mm. 68 Prepreg ( 60X magnification) Prepreg ( 200X magnification) Prepreg ( 400X magnification) D155 ( 200X magnification) DI55 ( 400X magnification) Figure 5.3. Micrographs of prepreg and D155 fabric composites D 15 5 fa br ic to w a re a, m m 69 0.85 . 0.80 '0.75 0.70 0.65 0.60 0.55 I i i i i stitclnng min stitching ▼ I I i / V-)si Fl-I W I f. ■____ ▼ Bi 1 1 Pitching ■ ■ f ■ . H ... ■ iW 0.30 0.35 0.40 0.45 Composite fiber volume fraction 0.50 0.55 Material DD7 - composite Vf = 0.54, D 155 tow Vf = 0.70 - 0.72 Figure 5.4. Composite fiber volume content versus D155 confined fiber tow area in Materials DD6, DD2 and DD7. 70 Fiber volume fraction micrograph of a D155 tow in a DD6 composite micrograph of a D155 tow in a DDlO composite (micrograph fiber volume fraction = 0.54) (micrograph fiber volume fraction = 0.67) Figure 5.5. Composite fiber volume fraction versus average number of fibers in contact with each other for materials DD6, DD5, DD2, DD9 and DD10. 71 Since the fabrics are-stitched or woven with a regular spacing, the tows can be stacked in or out of phase with the adjoining plies. Figure 5.6 shows three possible stacking possibilities. Each has some degree of tow compression and elliptical shape deformation with increasing average fiber content as the tow interacts with "adjacent tows. The D092 fabric is a lighter fabric with a larger distance between the fiber tows and thus larger matrix rich regions. With the tows stacked directly in phase with each other (strands on top of each other) the resin rich areas can extend continuously through the composite thickness. When the tows are out of phase with the adjacent tows, the resin ' rich areas between the tows are partly filled in by deformed tows from adjacent layers, allowing for higher fiber contents. Figure 5.6 shows the D092 fabric at fiber volume fractions of 0.30, 0.41 and 0.50. At a fiber content less than approximately 0.30, the tows in all the fabrics are separated from the adjacent plies by a continuous matrix layer, and therefore do not have any direct fiber contact with the tows in the adjacent ply. As the fiber content is increased, the tows start to contact the tows in adjacent plies, causing elliptical tows to flatten out and fill the resin rich areas between the adjacent plies. Increasing the fiber content further causes the tows to deform in the width direction, filling in resin channels between the tows, within the ply. If this deformation is restricted by the weave or stitching, a pinched region along the strand will exist. Since the stitching is physically on the surface above and below the tow, the stitch introduces additional “hard points” of contact, which cause localized pinching of the fiber tow as well as adjacent tows in contact with this stitching. This situation causes additional points of pinching. In the DD series of materials listed in the database, the stitching in the 72 D155 fabric starts to interact with the adjacent plies at a fiber volume fraction of approximately 0.36. This interaction effect is illustrated in Figure 5.7. Since the stitching thread is also on a regular spacing, the stitching in one ply can contact the stitching in an adjacent ply, creating another hard contact point or location of increased bundle fiber content. Figure 5.8 shows the interaction of the plies when the stitches are stacked on top of each other. The stacking of the stitching causes the plies to be separated more at the stitch points than between the stitches, causing the fibers to collapse into the resin rich region, creating a small fiber angle which might reduce the localized compressive strength. The figure shows the effects of removing the stitching thread from the D155 fabric. Without the restrictions of the stitching thread, the glass fibers disperse and form a more uniform geometry similar to the prepreg materials, minimizing the size of the matrix rich regions in the ply. resin rich region (black) Material D155K - V f = 0.33 Material D092D - Vf = 0.30 Material D 155K - V f = 0.33 Material D092B - V f = 0.41 Material D155K - V f = 0.33 Material D092G - V f = 0.58I mm Figure 5.6. Stacking geometries of unidirectional fiber bundles. 73 Material DD6 -V^= 0.36. Stitching between 0°and 45° Figure 5.7 Fabric stitching interaction with adjacent plies. The A130 fabric, which has a woven architecture shown in Figure 5.9, uses the same glass roving that is used in the D155 fabric. This fabric is woven around a weft glass strand which is coated with a thermoplastic hot melt adhesive. During fabric weaving, this strand thermoplastic bead is woven into the fabric. Heat is applied to melt the thermoplastic to encapsulate the glass strands in direct contact with it, locking the fabric architecture together. The bonding of the matrix materials to this thermoplastic bead is poor. Cracks readily form at the interface of this bead and the matrix for all the resin systems in the database. 74 X D 155 stitching stacked Adjacent tows contact eachother Z D 155 stitching offset \ > Edge of D155 tow Gray areas are matrix material Black dots are stitching Edge view of D 155 plies (stitching spaced about every 4 mm) Material D 155 -V f = 0.45 Between stitching Stitching thread Stitched D 155 tows Released D 155 tows (stitching has been removed) Figure 5.8. Fabric stitching interaction with adjacent ply stitching and the effects of removing the stitching. 75 DD ll-107, 414 MPa, R=O.I Figure 5.9. A130 fabric with woven architecture with cracking around thermoplastic bead in coupon DDl 1-107 after fatigue testing. In summary, the following effects have been observed in strand-fabric interactions: • Stitching or weaving is necessary in order to physically handle the fabric during composite manufacturing in low cost composites. • The stitch or weave causes a local pinching and misorientation of the strands. • The stitching causes the strand fiber content to locally increase periodically along the length of the strand. • The stitching thread interacts with the strands as a hard contact point. • The thermoplastic bead in the woven fabrics does not bond with the matrix materials used in this study and was a nucleation point for starter cracks. • The strands deform in cross-section as the composite fiber content increases. 76 Unidirectional fatigue behavior Background. Bulk glass and single glass fibers are not affected by the cycling of stress. However, inorganic glasses are affected by a stress-corrosion mechanism termed “static fatigue” where the tensile stress causing failure is reduced by 3 to 5 percent for each decade of time under load [33, 34]. This mechanism of stress-corrosion is caused by water molecules attacking the silica bonds of the glass, creating surface flaws, which propagate to produce failure [35]. The rate of this.process is increased strongly by impurities such as sodium. This mechanism appears to be independent from the cyclic fatigue behavior of the composites [36, 37, 38]. Higher sodium content glasses are more sensitive to this corrosion and their strength can be reduced by as much as 10 percent for each additional decade of time under load. The inherent fatigue behavior of individual glass fibers and strands has been reported in the literature [39-46] and is summarized in Table 5.1 and Figures 5.10 through 5.12. The individual fiber tests listed show the static fatigue (stress corrosion) mechanism inherent in bulk glass. The 500 pm diameter fiber had a complex composition which degraded at 9 percent per log decade. References 39 and 43 researched these 500 pm diameter fibers which could be manufactured with a surface compressive residual stress which eliminated the static, as well as the cyclic fatigue behavior of the glass. The major limitations of this fiber were their low initial strength compared to smaller, conventional reinforcing fibers and their high manufacturing cost. The surface compressed fiber data was not included in Table 5.1 or Figure 5.10. Figure 5,11 shows unimpregnated fiber strands containing 5, 30 and 210 fibers. 77 The fatigue sensitivity coefficient, b, (equation 4.2) of these strands increased to 7 to 10 percent per log decade of cycles from the 4 percent per decade of the individual fiber shown in Figure 5.10. References I to 19, 47 and 48 all demonstrate that non-woven glass reinforced plastics degrade with a fatigue sensitivity coefficient, b, of approximately 0.10 or 10 percent per decade. Figure 5.12 details the impregnated strand data with strands varying from 30 to 2040 fibers. These data also show a b-value of approximately 0.10. This fatigue behavior must be inherent to the glass fiber as both the unimpregnated and the impregnated strands have approximately the same b-value and this also suggests that the fatigue behavior of the composites derives directly from the glass reinforcement [41- 44]. The basic mechanism of fatigue degradation in these composites appears to be some sort of glass fiber surface abrasion or friction and wear process. Looking at one glass fiber, the smallest incremental distance that a crack can grow in the glass is the diameter of the silicate ring, which is 0.4 to 0.5 nm (10"9 m) [35]. Using fracture mechanics to estimate flaw sizes at fiber failure, glass has a fracture toughness (Kic) of approximately 0.7 MNZm3z2 and at a tensile stress (a) of 800 MPa (typical of fatigue tests to IO6 cycles), using K1 = 1.12 a (tt a)1/2 [50], the crack length (a) equals 1.9 x 10'7m or 190 nm. This is a crack length of a few hundred silica rings in a fiber that has a diameter of 12,000 nm (12pm). Attempts to find fatigue damage of this size on the glass strands have been unsuccessful. Fatigue damage generated on the surface of the glass fiber could not be differentiated from the longitudinal irregularities found on pristine fibers due to the fiber manufacturing process. 78 Results and Discussion. Only very limited fatigue data is available with results past a few million cycles. A b-value of 0.10 extrapolates (assuming a linear S-N curve on a semi-log plot) to zero strength after ten decades or 10 billion cycles. The slope of the fatigue trend must change slope at some level. In order to determine the high cycle behavior of impregnated glass strands, a specially constructed strand consisting of 45 fibers and a D155 strand of 2000 fibers were impregnated with polyester (CoRezyn 63- AX-051) and fatigue tested out to IO9 cycles at R=0.1. These tests are detailed in Table 5.2. These are the first known fiberglass fatigue results at IO9 cycles. The 45 fiber strand was tested on the speaker cone based fiber testing apparatus discussed in Chapter 3, and the results are presented in Figures 5.13 and 5.14, as well as listed in the database (Appendix A). Figure 5.14 shows two plotted trend lines: one semi­ log prediction line at 8.3 % / decade, with a corresponding statistical goodness of fit value (R2) of 0.95, and a log-log prediction line. The log-log prediction line had a higher corresponding statistical goodness of fit value (0.93) when the static data was included in the line fit (forced through I). The three fatigue coupons which went in excess of lx IO9 cycles, unbroken, are considered “run-outs” and were included in the prediction line calculations. All calculated stresses and strains are based upon the actual glass fiber cross sectional area and an elastic modulus of 70 GPa. The static tests were performed by attaching a twelve volt battery across the speaker terminals, which drove the speaker at a displacement rate of 140 to 150 mm per second, similar to the fatigue rate. Figure 5.15 shows a typical static test applied load versus time diagram. Most of the coupons failed in the gage section, with significant fiber failures and 79 transverse matrix cracks. The fiber volume fraction of the coupons ranged between 0.52 and 0.57. The polyester resin used to impregnate these fibers had an ultimate strain to failure of approximately 2 percent, and the test coupons showed numerous transverse matrix cracks along the strands length. The D155 strand of 2000 fibers was tested in the Instron 8511 servo-hydraulic testing machine and the data presented in Figures 5.16 and 5.17. Figure 5.17 shows three predicted trend lines: two log-log and one semi-log. The semi-log predicted trend of 8.8 percent per decade had the highest corresponding statistical goodness of fit value into the IO5 to IO6 cycle range (R2 = 0.99). Past this range, the power law prediction (linear on a log-log plot) incorporating only the fatigue data at stresses less than a normalized stress of 0.55 had a better fit (R2 = 0.97 versus 0.69 for the entire data set). Variability in Properties of Strands Taken From Fabrics. The D155 strands were carefully taken from different rolls of D155 fabric. A variation of the static strength of the D155 strands with different batches was noticed early on in the research and was monitored. Six rolls of D155 fabric were used to fabricate the materials in the database over a seven year period. Strands were carefully removed from these rolls, impregnated with polyester and statically tested. Thirty coupons were tested from each batch, and the scatter is detailed in the Weibull graph in Figure 5.18. The Weibull values of Eta (level at which 62 percent of the coupons have failed) and the Beta or Weibull modulus (m) are also listed in Figure 5.18. Roll I had the lowest strength of all the rolls tested. Figure 5.19 combines all the 300 static strength tests into one curve. Since most of the statistical tests 80 performed in this study required a normal or near normal statistical distribution, it was necessary to test the strength distribution to determine normality. Figure 5.19 shows the three best statistical models, and their coefficients for the data, as determined by the computer simulation program Unifit II, by Averill M. Law and Associates. The data are normally distributed. The strengths range from 912 N (3.1% strain to failure) to 1,487 N (5.1% strain to failure), again with roll I filling in the lower end of the curve. A Weibull modulus of 12.2 was obtained from the pooled data sets (all data), which is within the range for ceramic materials [49], but is much lower than the individual data sets from separate batches. Table 5.1. Summary of previous fatigue results on individual E-glass fibers and tows. Number of fibers Fiber diameter pm Matrix material and fiber volume fraction UTSZVf MPa R = 0.1 b R = 0.1 IO6 strain % A Reference I 25 none, I 2130 0.040 2.31 39 I 500 none, I 738 0.090 0.49 39,43 5 25 none, I 1490 0.068 1.26 40 30 25 none, I 1390 0.099 0.81 39 210 9 none, I 1530 0.091 0.99 41-44 30 25 epoxy, 0.40 2324 0.088 1.57 39 210 9 epoxy, 0.49 2255 0.096 1.37 41-44210 9 epoxy, 0.45 2158 0.091 1.40 210 9 polyester, 0.23 1980 0.100 1.13 2040 13 epoxy, 0.16, (R=O) 1672 0.1 15b 0.74 45,462040 13 epoxy, 0.33, (R=O) 1659 0.1078 0.85 2040 13 epoxy, 0.50, (R=O) 1556 0.093B 0.98 A IO6 strain calculated using E = 70 GPa__________ bR = 0 data 81 w 1.1 4% / decade ■ 1 V runout9% / decade0 0.8 — S 0.7 ^ 0.6 runout E 0.2 UTS — 2130 MPa, 25 |im diameter UTS = 738 MPa, 500 |im diameter 1E3 I E4 Cycles to failure Figure 5.10. Normalized S-N fatigue data for unimpregnated single glass fibers (References 39, 43). II I to 2 In - u.w ; ■ " - I ■ m 84 1400 Fiber coupon #142 Maximum load = 1396 grams 1200 1000 Time, milliseconds Figure 5.15. Applied tensile load versus time for a 45 fiber test coupon. I I CL CLro E3 E Cycles to failure Figure 5.16. S-N fatigue data for D155 impregnated fiber strand (2000 fibers, average diameter = 15.98 pm, SD = 1.53 pm), R = 0.1 (tested in a servohydraulic machine). 85 0 % I 0-8 ■a 1 0.6 a E Tg 0 .4 N CDI z 0.2 ' So = 2,750 VtPa S / ^ s / . 3o = I - 0. D88 Log N % Il P 99) -I •x . x / /S /So = BN n , E (R2 = Oi= 1.53, n )7) = 11.5 s /so = N (-1/ (R2 = 0 i), n = 14 94) x. ' C IEO 1E1 1E2 1E3 1E4 I ES 1E6 1E7 I ES 1E9 C y c le s to fa ilu re (N) Figure 5.17. Normalized S-N fatigue data for impregnated D155 fiber strand (20 0 fibers, average diameter = 15.98 pm, SD = 1.53 pm), R = 0.1. & 0.1 900 1000 1100 1200 1300 1400 1500 1600 Ultimate tensile strength, N ■ roll 1 a roll 2 T roll 3 ? roll 4b • roll 5 o roll 5b * roll 6 a roll 6b + roll 6c % roll 6d Figure 5.18. Strength distributions for strands from individual D155 rolls with Weibull fit parameters. 86 1 0.9 a; 0.8 a5 0.7 5 0.6 1 05 S 0.4 2 Q- 0.3 0.2 0.1 0 800 900 1000 1100 1200 1300 1400 1500 1600 D155 Ultimate tow strength, N Figure 5.19. Weibull distribution of pooled D155 strand ultimate tensile strengths from rolls I through 6. ,weibull_ Weibull (0, 1318.7, 12.24) Extreme Value Type A (1323.3, 104.26) Normal (1263, 128.5) normal extreme treme normal Fatigue tests were run with coupons from roll 4 and roll 5, which had significantly different static strengths (statistical p-value <0.0001), with the data shown in Figure 5.20. Although there was a statistical difference in the static strengths, past a fatigue lifetime of approximately a million cycles, little difference can be seen between the strands. This same check was performed on materials DD2 and DD2A in the database with the same conclusions (no difference). 87 1 4 0 0 1 inn — i r i I U T S b 106 s tra in 10^ s tra in — Roll 4 1105 0 .087 1 .9% 1.6% I RoIIS 1189 0 .097 1 .8% 1 .4% Z xT 1 0 0 0 g "5 0 0 0 "q . CLro IIIU □ H in i □ - 2 6 0 0 3 E c§ 4 0 0 — rrnrn [ *#, ■ a w m m 5 OQQ 0 -----1—I-H--I-H+ KOII 4 U KOII D ......i....I-UHTH.......I....H -H Mlj...... +...I ' ! - I- I- I - I r l .......I....I - I-H itt 1EO 1E1 1E2 1E3 1E4 1E5 1E6 1E7 Cycles to failure Figure 5.20. S-N fatigue data for D155 strands from D155 rolls 4 and 5. Unidirectional Laminates The strand data support the conclusion that the basic fatigue response is inherent in the glass fiber interactions. This section describes results for larger unidirectional specimens using laminates fabricated from fabrics, which include the complications of stitching, weaving and matrix rich areas. The unidirectional materials studied are listed in Table 5.3, with additional information about the fabrics and composites listed in the database. Various authors have reported that the degradation in composite materials under fatigue loading results from the accumulation of stable cracking in the matrix and fiber- matrix interface [51]. This stable cracking increases in severity with cyclic loading, resulting in the gradual decrease in mechanical properties until final failure by overloading. Figure 5.21, from Reference 51, shows the generally accepted progression of 88 damage in a composite during fatigue. Further information on fatigue damage accumulation can be found in Reference 51. It is believed that this increased amount of damage in the matrix and at the matrix/fiber interface is what decreases the larger coupon fatigue behavior from the individual strand behavior. DAMAGE MODES DURING FATIGUE LIFE 3 - Delaminollon Fiber Breaking !-Matrix Cracking Fiber Breaking 5- Fracture 2 -Crack Coupling ,Interfacial Debonding,Fiber Breaking 4 - Delomination Growth, Fiber Breaking (Localized) PERCENT OF LIFE Figure 5.21. Schematic representation of the development of damage during the fatigue life of a multidirectional composite laminate. [51] Figures 5.22 to 5.29 show the normalized fatigue data and the initial fatigue strains for the materials listed in Table 5.4. Even though the increasing fiber content raises the static modulus and ultimate tensile strength, the fatigue performance deteriorates significantly on either a normalized (b-value, equation 4.2) or absolute (strain at IO6 cycles) basis, as the fiber content increases. The latter parameter is the value of maximum initial strain which the material can withstand for IO6 cycles. 89 Table 5.3. Summary of fatigue properties for the unidirectional materials tested. R= 10 R = 0.1 Material* Vf UCS MPa bc strain for IO6 cycles, % UTS, MPa bT strain for IO6 cycles, % E GPa A060 0.41 -315 — — 579 0.094 0.80 31.4 A130C 0.35 -373 0.062 -0.70 728 0.091 1.10 31.6 A130G 0.55 -423 — 1,203 0.133 0.70 44.4 A260A 0.35 -440 — 776 0.090 1.11 31.1 CM 1701 0.38 -573 0.084 -0.93 796 0.126 0.64 30.5 DG72A 0 36 -560 0.075 -1.11 799 0.106 1.04 28.3 D092B 0.41 -675 — 908 0.104 1.03 33.8 DG92D 0.30 -540 — 731 0.090 1.25 25.4 D092F 0.50 -679 — 1,112 0.121 0.70 40.8 D092G 0.58 -692 0.085 -0.97 1,163 0.132 0.60 44.5 D155B 0.39 -653 0.077 -1.10 854 0.102 1.12 31.5 D155C 0.51 -794 — 1,187 0.120 0.90 38.9 D155G 0.59 -765 0.057 -1.00 1,314 0.138 0.64 47.0 D155H 0.49 -755 — 1,121 0.099 1.07 38.3 D155 J 0.58 -776 — 1,142 0.108 0.80 47.9 D155K 0.33 -551 — — 861 0.114 098 28.1 * Reinforcing fabric designation followed by a letter designation where more than one fiber content was tested for that fabric (see Appendix A for more details). In all cases, the IO6 cycle strain was less than I percent for Vf > 0.50. Materials D155H and D155J had the stitching thread removed from the gage length prior to RTM manufacturing, which caused an IO6 cycle strain improvement from 0.64 to 0.80 percent strain at a fiber volume fraction of 0.58. The tensile strength of the D155J (no stitching) was lower than D155G, which probably resulted from some minor strand misalignment and/or the strength variation noted earlier for the D155 fabrics. 90 1.2 £ 1 CO 2 0.8Tm I 0.6I E 0.43 E X I 0.2 0 1EO IE I 1E2 1E3 I E4 1E5 1E6 1E7 Cycles to failure Figure 5.22. Normalized fatigue data for fabrics D072 and D092, R = Ol. Material Vf% UTS, MPa t>T strain for IO6 cycles, % E, GPa V D072A 36 799 0.106 1.10 28.3 - D092B 41 953 0.104 1.10 33.8 D092D 30 731 0.090 1.25 25.4 - D092F 50 1,112 0.121 0.70 40.8 * D092G 58 1,163 0.132 0.65 44.5 -Air- 1 . - I I i m n - 4.0 3.5 Se 3.0 I 2.0 1 “ 5 1.0 0.5 0 — — — Material Vf% UTS, MPa t>T strain for IO6 cycles, % E, GPa v D072A 36 799 0.106 1.10 28.3 - D092B 41 953 0.104 1.10 33.8 - D092D 30 731 0.090 1.25 25.4 - D092F 50 1,112 0.121 0.70 40.8 ' A D092G 58 1,163 0.132 0.65 44.5 — — ^ V * A ■ - V a * A A < ■ a * ^ — — — AA i . V - . A " . ----1 !-■L-- A ^AAA L -----1 I H-Hif ----1 I I I Hll ----1 I I HIM --- t i l l HH----1—I H Hll ----1 I I I Illl ----b I H Illl 1EO 1E3 I E4 Cycles to failure 1E6 F igure 5 .23. M ax im um initial fatigue stra in da ta fo r fab rics D 072 and D 092 , R = 0 .1. 91 I 1 g 0.8 TB I 0.6 I E 0.4L Material Vr% UTS, MPa br strain for 10* cycles, % E, GPa - DlSSB 39 854 0.093 1.12 31.5 ▼ DlSSC SI 1,187 0.118 0.90 38.9 • DlSSG 59 1,314 0.138 0.64 47.0 A DlSSH 49 1,121 0.094 1.07 38.3 V DlSSJ 58 1,142 0.108 0.90 47.6 A DlSSK 33 831 0.114 0.98 28.1 1 r ' Materials D155H and D155J had no weft stitching in the gage length I i i i in i i' i i mu 1EO 1E3 1E4 Cycles to failure 1E6 Figure 5.24. Normalized fatigue data for D155 fabrics (with and without stitching), R = 0.1. strain for IO6 cycles, % Material D155B 0.093 DlSSC 0.118 DlSSG 0.138 DlSSH 0.094 DlSSJ 0.108 DlSSK 0.114£ 2.5 ^ 2.0 1E0 1 El 1E2 1E3 1E4 1E5 1E6 1E7 Cycles to failure Figure 5.25. Maximum initial fatigue strain for D 155 fabrics (with and without stitching), R = 0.1. 92 1 1 s' 2 0.8 00 I I C E3 E 0.6 Material Vf% UTS, MPa bT strain for IO6 cycles, % E, GPa * A060 41 579 0.094 0.80 31.4 - A130C 35 728 0.091 1.10 31.0 A130G 55 1,203 0.138 0.70 44.4 • A260A 35 776 0.092 1.11 32.5 M — T * * J * - I - ’ t - K V r ----1—h-f ■< Hll 1EO I E3 1E 4 Cycles to failure 1E6 Figure 5.26. Normalized fatigue data for woven fabrics (A060, A 130 and A260), R = 0 .1. strain for IO6 cycles, %Material A060 0.094 ge 3 .0 A130C 0.091 A1300 0.138 A260A 0.092 2.0 g 15 Cycles to failure Figure 5.27. Maximum initial fatigue strain data for woven fabrics (A060, A 130 and A260), R = 0.1. 93 Figures 5.28 and 5.29 show the fatigue data for the standard and the thickness tapered unidirectional coupons for materials A, B and L (database material designations). These materials had some fiber misalignment away from the 0° load direction (up to 4°), which provided a lower static strength and reduced fatigue lifetimes but showed similar fatigue trends as the other unidirectional materials. The tapering reduced the amount of damage present in the coupon ends (hydraulically clamped areas), which improved the failure mode and the fatigue lifetime. Materials A and L had resin rich regions on the outside surfaces which, when thickness tapered, reduced the composite thickness without removing a representative amount of fiber, resulting in an overall longitudinal modulus increase. Table 5.4 and Figure 5.30 give the tensile and compressive ultimate strains and the normalized fiber strength (UTS / VF); dividing by Vp gives the stress per unit area of glass fiber, ignoring the matrix. The impregnated D155 strand average strength was 2,750 MPa, while the D155 composites averaged 2,220 MPa, which is a strength reduction of 19 percent; this reduction is probably due to the interaction with other strands and stitching, along with increased matrix cracking. The lighter weight A060 had a low tensile ultimate strain of 1.9 percent and a UTSZVf ratio of 1,412 MPa, which indicated load carrying problems in the composite. Further inspection of the material determined that the weaving weft and thermoplastic bead were the same that were used for the heavier woven fabrics, giving a great out of plane distortion relative to the tow diameter. 94 1.2 w 1-0 ■ O □■ «• • □ a • — i i i mu — i i i mu — i i11 mi --- 1—+-I-HlU— i I Him— i- i i inn —i—t mill — i i 11 nit ge 3.0 I 25 I 2.0 I:: o.o Material > * UTS,MPa bT strain for IO6 cycles, % E, GPa - A 30 566 0.111 0.87 21.5 O A (tapered) 30 571 0.100 0.98 24.6 • B 30 581 0.135 0.99 21.0 * L 50 742 0 135 0.80 32.6 V L (tapered) 50 752 0.127 0.65 38.6 e • nT * ▼DD ■ • „ 1 7 o • V % %.* ■ ^ o * ---- I-H--H-Bl--- 1 --H- HBl --- 1 I I Illll ---1 I I HIM---B-I-H-FBl---B-H-HtH—I- BHim— I I I mu IEO 1E2 1 ES 1E4 1 ES Cycles to failure 1E6 1E8 F igure 5.29. M ax im um initial fatigue stra in da ta fo r industrial m ate ria ls A , B and L (w ith and w ithou t th ickness tapering), R = 0 . 1. 95 Table 5.4. Summary of static properties for the unidirectional materials tested. Material v F UCSMPa Compressive failure strain, % UTS, MPa Tensile failure strain, % E GPa UTS / Vf MPa A060 0.41 -315 -1.0 579 1.8 31.4 1412 A130C 0.35 -373 -1.4 728 2.4 31.0 2080 A130G 0.55 -423 -1.1 1203 2.7 44.4 2187 A260A 0.35 -440 -1.4 776 2.5 31.1 2217 CM1701 0.38 -573 -1.9 796 2.6 30.5 2095 DQ72A 0.36 -560 -2.0 799 2.8 28.3 2219 D092B 0.41 -675 -2.0 908 2.7 33.8 2214 DQ92D 0.30 -540 -2.1 731 2.9 25.4 2437 D092F 0.50 -679 -1.7 1112 2.7 40.8 2224 D092G 0.58 -692 -2.0 1163 2.6 44.5 2005 D155B 0 39 -653 -2.2 854 2.7 31.5 2190 D155C 0.51 -794 -ZO 1187 3.1 38.9 2327 D155G 0.59 -765 -1.6 1314 2.8 47.0 2227 D155H 0.49 -755 -2.0 1121 2.9 38.3 2288 D155J 0.58 -776 -1.6 1142 2.4 47.6 1969 D155K 0.33 -551 -2.0 861 3.1 28.1 2609 3000 2800 2600 2400 2 2200 > 2000 P 1800 1600 1400 1200 1000 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 — I I I I I I I I /"VVCI a g c IV l J J SLI a n u s LI C IIg l U Z / - u iv i r a ; m ■ ■ ■ M ■I U — J I I — — — ...- — — X060 — — Fiber volume fraction Figure 5.30. Fiber tensile strength (UTSZVf) versus fiber content for unidirectional materials. 96 The thermoplastic bead was coating approximately 5 to 7 mm of the A060 strand every 30 mm, which did not bond to the matrix material and reduced the performance of the composite. Figure 5.31 details the ultimate compressive stress versus the fiber volume fraction. The fabrics with the well aligned fibers form an increasing trend with VF, while the woven fabrics (A060, A130 and A260) all fall significantly below this performance. Figure 5.32 shows the compressive failure strain versus the fiber volume fraction. As the fiber content increases, the compressive strain to failure decreases. The increasing compressive strength of the D155 fabric with Vf is more than offset by the increasing modulus, so the ultimate strain to failure decreases significantly with increasing VF. The woven fabrics have a low ultimate compressive strain which does not significantly change over the fiber volume fraction range of 0.30 to 0.60. 800 ra 1 700 %"2to £ 600 I E 8 500 S I 3 400 300 0.25 0.3 0.35 0.4 0.45 0.5 0.55 0.6 0.65 Fiber volume fraction Figure 5.31. Ultimate compressive stress versus fiber volume for unidirectional materials. ■ ■ ■ - ■ A26 OA : A130C ■ A060 ..........A l 3 O Q 97 ae Eto 23 S I I Ol E O 1.6 1.4 1.2 1 I - ■ ■ ■ I ■ ■ ■ A l 3 J OC O — — A26 OA A13 / l0 6 0 Fiber volume fraction Figure 5.32. Compressive failure strain versus fiber volume for unidirectional materials. Figure 5.33 shows the tensile million-cycle strain (R=0.1) versus fiber content. As the fiber content is increased, the million-cycle strain decreases. Thus, there is a significant transition to increased fatigue sensitivity in the fiber content range shown. Both the woven and the stitched fabrics are converging to the same strain at fiber volume fractions greater than 0.55. The D155H and D155J materials, which had the weft stitching removed, show the same strain reduction behavior with fiber content as the other unidirectional materials, but the transition occurs at a higher VF, and their overall strain performance was significantly higher than the stitched or woven fabrics (shifted to the right in Figure 5.33). Figure 5.34 shows the fatigue coefficient, b (R=OT), changing with fiber content, again with the non-stitched materials performing better. As noted earlier (Figure 5.5), the number of fiber contacts also increase in the range of fiber volume 98 fraction from 0.3 to 0.4, which may partially explain this trend. Figure 5.35 shows the normalized compression (R=IO) data for the various unidirectional materials. Except for the woven A130C material, the stitched fabric materials showed some ultimate compressive strength increase with increasing fiber content, but the strain at one million cycles was relatively unchanged (-0.97 to -1.11 percent strain) for this group of materials. The tensile behavior for the fiber strands compared with that of the composites are shown in Figure 5.36. The strands show better performance (as expected) than the composites, apparently due to a smaller volume and a lack of interaction with matrix cracks and other plies. The composites have a fatigue strain performance of approximately 50 percent of the strand strain, depending on VF; a similar ratio exists in the static tensile data at N = I. The D155H and D155J materials have a strain performance slightly higher than the other composites, but few points were tested past IO6 cycles to determine if this performance holds at higher cycles. The lower Vf composites are following a similar trend (b-value) as the strand data, and there appears to be a change in the slope of the trend line in the IO7 to IO8 cycle range. More composite data in this cycle range is required to determine if the slope is changing enough to attain a fatigue limit, or whether it is simply following a power law trend. 99 1 .3 1.2 Se 1.1 0) o 0 .9 5 0.8 0 .7 0.6 0 .2 5 0 .3 0 .3 5 0 .4 0 .4 5 0 .5 0 .5 5 0 .6 Fiber v o lum e fraction Figure 5.33. Million cycle tensile strain versus fiber volume for unidirectional materials, R=O.I. ▼ A 06 0 , A l 3 0 , A 2 6 0 x D 07 2 Bi D 09 2 ■ D 1 5 5o D l 5 5 (n o stitch ing ) .. I: r\ \ \ \ _^_ \ \ \ \\ \ X \ \\ \ V \ X 0 .1 4 0 .1 3 L I g 0.11 fLi. 0.1 0 .0 9 0 .2 5 0 .3 0 .3 5 0 .4 0 .4 5 0 .5 0 .5 5 0 .6 F iber v o lum e fraction Figure 5.34. Tensile fatigue coefficient, b, versus fiber volume for unidirectional materials. S/So = I - b Log N ~ t— m — r V A 0 6 0 , A l 3 0 , A 2 6 0 • D 0 7 2 , D 0 9 2 ■ D 1 5 5 r / 7 7 > r / LV I Ux, V IU ailLUII "U/ ......V X VX X X .A X / x 7" / y / 100 strain for IO6 cycles, %Material A130C 0.080 -0.77 D072A 0.075 D092G 0.085 -0.97 D155B 0.077 D155G 0.057 Cycles to failure Figure 5.35. Normalized compressive fatigue data for various unidirectional materials, R=10. a? .s'SE "5> 3.0 is I 2.0 I 1.0 0.0 ■ D155B I = D155C z D155G ’ D155H ■ D155 J - D155K * High Cycle a 45 fibers * D155 Tow I Strand tests --------------------- O0 laminates — 4 z 4 8 ZZ s tN T _ a —m --- ^ A z« ,A& ^ A : > t ... S z Z B...AA .ZW f i ... 1E0 I E4 1 ES Cycles to failure 1 ES 1E10 Figure 5.36. Comparison of maximum initial fatigue strain data for various unidirectional materials and impregnated strand tests, R = 0.1. 101 ±45° Fabrics Three different ±45° stitched fabrics at multiple fiber contents were fatigue tested: DB 120, DB240 and DB400; the data are summarized in Table 5.5 (these tests were conducted with the load in the 0° direction). The ±45° materials are expected to behave differently from the 0° materials because they are matrix dominated. The ±45° materials fail by the growth of matrix cracks parallel to the fibers of each ply, followed by the interlaminar separation of the plies. The DB 120 fabric is the same ±45° fabric used in the construction of the CDB200 triax fabric; the DB240 fabric uses the same glass strand that is used in the D155 and A130 fabrics. Additional static and fatigue tests were performed on materials using orientated D155 fabric, in a (±45°)3 composite using different matrix materials. Due to difficulties in maintaining a ±45° lay-up with the DB 120 and DB240 fabrics, the D155 fabric was used to control the fiber angles so that any variability seen would not be due to the fiber orientation. Figure 5.32 shows the normalized maximum stress diagram for the materials constructed with the DB 120 fabrics under tension-tension (R=OT) and compression- compression (R=IO) fatigue loading. The DB240 and DB400 fabrics showed similar normalized stress trends. Figure 5.37 includes fatigue data from material CH20, which consisted of the DB 120 fabric stitched to a glass mat, and the 3M-SP250 prepreg data. Figures 5.38, 5.39 and 5.40 show the maximum initial strains for these ±45° composites; generally, the compressive (R=IO) fatigue strain is higher than the tensile (R=OT) strain (as expected). An interesting observation about these two figures is that the prepreg 102 Table 5.5. Summary of the ±45° materials tested R= 10 R = 0.1 Material Vf % UCS, MPa bc strain for IO6 cycles, % UTS, MPa bT strain for IO6 cycles, % E GPa DB 120 fabrics CH20 25 -230 — — 133 0.118 0.38 10.9 CH5 28 -190 0.105 -0.85 139 0.123 0.54 8.5 CH4 40 -171 0.112 -0.48 155 0.124 0.48 11.4 CH9 49 -174 0.106 -0.67 151 0.133 0.51 10.3 DB240 fabrics CHlO 33 -163 0.126 -0.64 120 0.108 0.58 8.1 CH 45 -178 0.105 -0.50 145 0.104 0.46 13.6 CHll 54 -189 0.106 -0.58 134 0.114 0.38 13.4 DB400 fabrics CH8 39 -146 0.151 -0.35 93 0.113 0.38 10.0 CH9 49 -174 0.106 -0.67 151 0.133 0.51 10.3 3M-SP250 Prepreg PP45 54 -160 — — 155 0.101 0.34 17.9 Angle plies manufactured with D155 fabric and different matrix materials ±45 P 38 -138 0.089 -0.65 107 0.109 0.40 9.79 ±45 V2 36 -149 0.085 -0.71 136 0.119 0.45 10.3 ±45P2 40 -160 — — 96 0.109 0.35 11.4 ±45 V 40 -154 — — 121 0.110 0.40 10.7 90 P 38 -123 0.062 -1.00 27 0.083 0.20 7.34 90V2 38 -171 — — 54 0.107 0.21 8.85 90 V 40 -167 — — 49 0.108 0.18 10.3 90 E2 38 -152 — — 40 0.110 0.18 7.28 Matrix Abbreviations: E2 -Epoxy (SC 14), P -Ortho-polyester (COR63AX051), P2 -Iso-polyester (COR75AQ010), V-Vinyl ester (Derakane 411C), V2 -Vinyl ester (Derakane 8084) 103 1.2 1.1 F 2 0.8 to I 0.7 I 0.6 I 0.5 I 0 4 g 0.3 I 0.2 0.1 O w r ' L M I I ■ CH5 • CH9 □ CH5 o CH9 D x 3M-SP250(R=0.1) I - v CH4 I % CH2C W V v # X % v_ ^ 2 - Q W X a x P O g s * ▼ ▼ ■ W R = ID.1 (solid sy 0 (open sy mbols) R = mbols) ------- 1 i i i tin — i— H-H-nt — ■ i 11 mi - - - - - - 1 I I I Mil - - - - - -1 ' I I I Hll ----- I-I -I HIM — i i 11 mi IEO 1 ES I E61E1 1E2 1E3 1E4 Cycles to failure Figure 5.37. Normalized Fatigue SN data for materials with DB 120 ±45 fabric (R=0.1 and 10). 2 . 2 - O ▼ CH4 i i ■ CH5 • CH9 a CHS o CH9I A v CH4 ^ 1 6 I ! x CH2 0 x 3M-SP2 I c - I . O I S 1 4 : i n r m ^ 1 4 ! t o 1 O X r □ □______TO I / - 1 - W V X 3 OQ VW ^ ^7 V • * . x : co oC U . o x m n R W ▼ 3 • CV V mm O ^ U . D n a R = O/ (solid sym (open sym bo Is) X V n o R = 10 ools) u.z 0 — I I i I mi — i n i mi — I I 11 mi — i i 11mi ---- I-I--H-Hlt — I I 11 mi — i i 11 mi 1EO IE I 1E2 1E3 1E4 1E5 1E6 1E7 Cycles to failure Figure 5.38. Initial fatigue strain data for materials with DB 120 ±45 fabric (R=0.1 and 10). 104 2.2 2 1.8 55 1.6 I 14 I 1-2 I 0.8 '8 I 0.6 0.4 0.2 0 IEO I E1 1E2 1E3 I E4 1 ES 1E6 1E7 Cycles to failure Figure 5.39. Initial fatigue strain data for materials with DB240 ±45 fabric (R=0.1 and 10). EL_ CH ■ CH10 • CH11 CH □ CH m o CN11 CD ▼ V , , ir _________ CO CI V am _ n n a e V %Sb TW Tl I I V V ^ ▼ g o o * O _p ■ C] R = 0.1 (solid symt (open symb 30 Is) T 4% R = 10 ols) ------- I - I -H -H t t ------1 I I I IHl ------1 M l l l l l — I I 111 III ------1 I I I H 11— I— I 111 111— I I 11 Illl 2.2 2 1.8 1 1-4 1 1 I 0.8 I 0.6 0.4 0.2 0 CH8 ▼ 3H8 v ■ CH9 CH9 U I i Il cI HT^ r UD W V □ □ a TW V R = O 1 (solid symt (open symb ols) ■ C □ U R = 10 ols) ------ 1 I I I M i l — i i 11 m i ---- I - I - H - I l l l ---- 1 I I I I l l l — I I I l l l l l — I I 11 I l l l — 1 1 1 1 m i 1EO I E3 1E4 Cycles to failure 1E6 Figure 5.40. Initial fatigue strain data for materials with DB400 ±45 fabric (R=0.1 and 10). 105 1.2 1 o 1-1 8 <0 0.9V) I 0-8 I 0.7 I 0.6 I 0.5 "S 0.4N re 0.3 6 0.2 z 0.1 R = IO R = 0 .1 M a te r ia l V r % ucs, M P a W s t r a in f o r IO 6 c y c le s , % U T S , M P a h r s t r a in f o r IO6 c y c le s , % E G P a ± 4 5 P ( o r t h o p o ly e s t e r ) 3 8 -1 3 8 0 .0 8 9 -0 .6 5 1 0 7 0 .1 0 9 0 .4 0 9 .7 9 ± 4 5 V 2 (8 0 8 4 ) 3 6 • 1 4 9 0 .0 8 5 -0 .7 1 136 0 .1 1 9 0 .4 5 1 0 .3 ’ ± 4 5 P 2 ( is o p o ly e s t e r ) 4 0 -1 6 0 . . . . — 96 0 .1 0 9 0 .3 5 1 1 .4 ± 4 5 V ( 4 1 1 C -5 0 ) 4 0 -154 . . . . . . . . 121 0 .1 1 0 0 .4 0 1 0 .7 R = O I (solid symbols) R = 10 (open symbols) ■ r * " ' U ■ I I i mi i i i 11 1E0 1E3 1E4 Cycles to failure IE6 ■ ortho polyester ▼ 8084 • iso polyester ▲ 411C-50 □ ortho polyester v 8084 ° iso polyester a 411C-50 Figure 5.41. Normalized fatigue SN data for ±45 composites constructed with D 155 fabric and different matrix materials (R=0.1 and 10). 1.6 1.4 ^ 1.2 h I 0.8 I 0.6 I 0.4 I) I □e MD A A nm * I .aA1. □ o n 7 V J• •I V -R = 0.1 (solid symbols) R= 10(open symbols) Ti - - - - - - I l l l I l l l — I I 11 m i - - - - - ! - + - H - I H l - - - - - 1 I I I HH - - - - - 1 I I Mi l l — I - I - I I I l l l — I - I l l I l l l 1EO 1E6IE I 1E2 1E3 I E4 1E5 Cycles to failure ■ ortho polyester ▼ 8084 • Iso polyester a 411C-50 □ ortho polyester v 8084 o Iso polyester a 411C-50 Figure 5.42. Initial fatigue strain data for ±45 composites constructed with D155 fabric and different matrix materials (R=0.1 and 10). 1 0 6 C 0.5 Fiber volume fraction ■ DB120 ▼ DB240 • DB400 x SP350 □ P v V2 o R2 Figure 5.43. Million cycle strain versus fiber volume fraction for ±45 materials. Fiber volume fraction ■ DB120 ▼ DB240 • DB400 x SP350 □ P v V2 o R2 a v Figure 5.44. Tensile fatigue coefficient, b, versus fiber volume fraction for ±45 materials. 107 material shows higher than average normalized stress behavior, while performing below average in fatigue strain. The DB 120 fabric provided a higher static strength for a specific fiber content than the DB240 or DB400. Above a fiber volume fraction of approximately 0.45, the tensile strength and modulus of these composites start to decrease with increasing fiber content; a reason for this has not been determined, but may be associated with an increase in micro-porosity within the strands. Thinner plies have been reported to have a higher fatigue resistance due to reduced resin thickness and interlaminar stresses [52-56]. Figures 5.41 and 5.42 show the fatigue data for the D155 constructed ±45° materials using four different resins. Despite the matrix dominated properties of the ±45° materials, there is no significant fatigue difference in the performance of the different resins under R=0.1 or 10 fatigue loading. The results are similar to the results of the 90° materials tests, also listed in Table 5.5 Figure 5.43 details the million cycle tensile strain versus the fiber volume fraction, and Figure 5.44 shows the tensile fatigue coefficient, b, versus the fiber volume fraction. No consistent fatigue trends with fiber volume content are evident for the ±45° laminates Materials With Varying Amounts of ±45° and 0° Plies The ±45° and 0° fabrics were assembled in different combinations to obtain different percentages of 0° plies in the composites. The design of structures like turbine blades or I-beams require a material with a high shear strength and modulus for the web and a material with a high axial strength and modulus for the main spar caps and flanges. 108 Higher ±45° content provides higher shear properties, while high 0° content provides high axial properties. While these are the main drivers in the engineering of laminates, all the materials must have adequate fatigue resistance at the strain levels imposed in service. Fatigue Trends Figures 5.45. through 5.56 detail the fatigue resistance in terms of normalized maximum stress and the maximum initial strain for the materials with 16, 24, 28, 39, 50 and 55 to 63 percent 0° plies at R=0.1 and 10; these materials also differ in overall fiber content as noted. Materials with 16 percent 0° (Figure 5.46) behave similar to the ±45° fabrics previously discussed, with the compressive fatigue strains being at or better than the tensile fatigue strains. At 24 percent 0° (Figure 5.48) the tensile fatigue strains are higher than the compressive strains for most of the fatigue trend and converge around IO6 cycles. For materials with increasing amounts of 0° material (28, 39 and 50 percent), the difference in initial fatigue strain performance between tensile (R=0.1) or compressive (R=IO) fatigue at IO6 cycles becomes smaller, and at 55 to 63 percent 0° (Figures 5.55 and 5.56), the fatigue trends of the materials show a reduced amount of scatter. These figures show the FF materials (FFA, FFB, FFC, FFD and FFF) which all had the same fabrics, but with different lay-ups, to study the effect of ply stacking sequence. There were no statistical differences between the materials or their failure modes with these fabrics and a fiber volume fraction of 0.38. This may not be observed if significant flaws were introduced, [57] studying carbon fiber composites with 0°, ±45°, and 90° plies with through thickness holes did find a difference of fatigue properties with stacking sequence. 109 Table 5.6. Summary of materials with 16 to 63 percent 0’s. R= 10 R = 0.1 Material (% 0's) Vf % UCS, MPa bc strain for IO6 cycles, % UTS, MPa bT strain for IO6 cycles, % E, GPa 16% 0’s (D092 0° and DB240 ±45°) CH19 33 -252 0.122 -0.65 193 0.102 0.70 11.9 CH18 47 -298 0.105 -0.74 294 0.129 0.50 17.2 24% O s (0155 0° and DB240 ±45°) CH3 36 -318 0.127 -0.60 336 0.112 0.64 16.8 CH2 41 -342 0.110 -0.70 362 0.127 0.65 16.7 CH13 48 -385 0.107 -0.60 423 0.145 0.48 23.2 28% 0's (D092 0° and DB120 ±45°) CH15 32 -345 0.100 -1.02 309 0.103 0.85 14.8 CH16 40 -309 0.085 -0.80 360 0.129 0.68 18.5 CH17 48 -301 0.079 -0.94 359 0.139 0.40 17.6 39% 0's (D155 0° and DB120 ±45°) CH23 32 -448 0.106 -0.90 394 0.140 0.40 18.5 CH12 34 -451 0.092 -1.15 398 0.099 0.94 17.4 CH14 44 -412 0.081 -1.00 517 0.134 0.75 21.0 CH6 49 -408 0.100 -0.80 502 0.139 0.50 21.5 50% 0's (various triax materials) R 31 -330 — — 441 0.104 0.98 16.5 AA 35 -348 0.081 -0.95 452 0.140 0.50 18.8 N 36 -318 0.096 -0.70 468 0.140 0.46 19.3 AA4 37 -449 — — 377 0.105 0.67 20.4 M 38 -286 — — 516 0.141 0.40 20.7 AA3 51 -284 — — 478 0.140 0.40 25.2 55 to 63% 0's (DIO0, 0155, A130 0° and DB120 ±45° ) CC (55) 39 -459 — — 561 0.121 0.80 21.7 FFA (56) 38 -553 — — 716 0.123 0.80 24.2 FFB (56) 38 -506 — — 621 0.119 0.80 23.4 FFC (56) 38 -499 — — 624 0.121 0.79 22.9 FFD (56) 38 -542 — — 636 0.120 0.83 23.1 FFF (56) 38 596 — — 664 0.123 0.80 23.9 BB (62) 42 -308 — — 725 0.131 0.80 25.2 CC2 (63) 45 -527 — — 715 0.118 0.79 26.6 CC3 (63) 45 -541 — — 682 0.112 0.85 26.3 no Table 5.7. Summary of Materials with 69 to 85 percent 0° plies. R= 10 R = Ol Material (% 0's) Vf % UCS, MPa bc strain for IO6 cycles, % UTS, MPa bT strain for IO6 cycles, % E, GPa P (69) 40 -466 0.094 -0.66 667 0.134 0.48 22.5 DD22 (70) 30 -389 — — 549 0.100 1.13 19.6 DD24 (70) 39 -511 — — 730 0.115 1.05 23.9 DD6 (72) 31 -505 0.071 -1.40 605 0.100 1.15 21.1 DDl 1(72) 31 -319 0.090 -0.70 592 0.100 1.20 20.0 DD14 (72) 35 -428 — — 728 0.133 0.60 25.1 DD5V2 (72) 35 -605 0.064 -1.66 787 0.102 1.39 22.3 DD5E (72) 36 -521 0.056 -1.42 674 0.102 1.10 23.6 DD5P (72) 36 -574 0.072 -1.35 661 0.101 1.16 24.2 DD5V (72) 36 -530 0.057 -1.48 675 0.102 1.11 23.7 DD5 (72) 38 -534 — — 724 0.104 1.15 25.2 DD2 (72) 42 -581 0.079 -1.15 752 0.110 0.95 27.0 DD2A (72) 42 — — — 986 0.122 0.94 28.0 DD8 (72) 42 -582 — — 778 0.102 0.90 27.1 DD12 (72) 43 -302 — — 723 0.114 0.85 26.4 DD4 (72) 50 -541 — — 886 0.136 0.55 31.0 DD13 (72) 50 -314 0.094 -0.45 821 0.130 0.80 29.5 DD7 (72) 54 -581 0.072 -1.03 832 0.147 0.40 32.0 DD9 (72) 54 -556 — — 907 0.137 0.46 34.6 DDlO (72) 62 -552 0.052 -0.90 956 0.143 0.35 42.5 DD20 (73) 34 -313 — — 587 0.137 0.50 22.2 DD20A (73) 37 — — — 639 0.142 0.50 25.3 DD (76) 49 -788 — — 910 0.135 0.60 31.3 GG (84) 40 -628 — — 970 0.116 1.10 28.0 X (85) 35 -438 0.070 -1.00 612 0.091 1.05 25.4 Tf (85) 39 -454 0.059 -1.00 626 0.102 0.97 25.0 I l l 1.2 I0 § 2 0.8 In 1 I 0.6 I I 0 '4m EI 0.2 R = 10 R =O .1 Sj Material Vr % OCS, MPa be strain for IO6 cycles, % UTS, MPa br strain for IO6 cycles, % E, GPa [ ] CH18 47 298 0.105 -0.74 294 0.129 0.50 17.2 CH19 33 252 0.122 -0.65 193 0.102 0.70 11.9 . — -----------------------1 D — V -W -— t f l ■ BH ▼ ▼ C d W ▼ C O ▼ ▼ R = 0 . (solid sym (open sym bols) R = 10 bols) — ! i n m i -------1 I I I Hl l -------1 I I I Il l l — I I I I Il l l — i— i - i m u ------- 1— H I Il l l ------- F - l-t-FH Il 1EO 1E2 1E3 I E4 1E5 1E6 Cycles to failure CH18 ■ CH19 v CH18 □ CH19 Figure 5.45. Normalized S-N fatigue data for materials with 16 percent 0° plies, [±45/0/±45]s layup with D092 and DB240 fabrics, R=0.1 and 10. 2 ge I 1.5 I I ' Ii [] Ii T TT Ii V „□ V ^ V ii□ v% ▼ ▼ a n ▼ nC ▼ ■ R = 0.1 R = 10 -------f-H-B-W (solid symt (open symb ------1—H-H+H .. I l — I l l l Illl ------1 I I I Mil— F-M-imi — i i11mi 1E0 1E1 1E2 1E3 1E4 I ES 1E6 Cycles to failure T CH18 ■ CH19 v CH18 □ CH19 Figure 5.46. Maximum initial fatigue strain data for materials with 16 percent 0° plies, [±45/0/±45]s layup with D092 and DB240 fabrics, R=0.1 and 10. 112 1 1 s 2 0.8 v> E I 0.6 CO E CO EI 0.2 R = 10 R=C .1 Vr u c s , bt strain for UTS, bj strain for E, .... Material % MPa IO6 cycles. MPa IO6 cycles. GPa % % - CH2 41 -342 0.110 -0.70 362 0.127 0.65 16.7 CH3 36 -318 0.127 -0.60 336 0.112 0.64 16.8 .... CHl 3 48 -385 0.107 -0.60 423 0.138 0.48 23.2 1CA'V w V W O D .....ww'V D O O R = 0.1 (solid symbols) R = 10 (open symbols) i n i n i -H-H -H - - I - - II 1EO 1E61E1 1E2 1E3 1E4 I ES Cycles to failure ▼ CH2 ■ CH3 • CH13 □ CH2 v CH3 o CH13 Figure 5.47. Normalized S-N fatigue data for materials with 24 percent O0 plies, [±45/0/±45]s layup with D155 and DB240 fabrics, R=O. I and 10. I 2 I 1.5 I ' IIt I------------- ▼ ■ — -------------- El O e ■ # ) 'ScF c ...CD** J V7 OO ...inn..J!....... ■ a , O v Dv w 1 . 5 R = 0.1 (solid symt (open symt DOls) %»°v R=IO iols) , -----IM I Illl ----1 I I I Illl — I l l l Illl ----I-M-HlH— I I 11Illl — t i l l Illl — I- I I l Illl 1EO I E1 1E2 1E3 I E4 I ES 1E6 1 Cycles to failure ▼ CH2 ■ CH3 • CH13 □ CH2 v CH3 o CH13 Figure 5.48. Maximum initial fatigue strain data for materials with 24 percent 0° plies, [±45/0/±45]s layup with D155 and DB240 fabrics, R=O. I and 10. 113 1.2 CO 1 2 0.8 to E E 0.6 X OJ E I 0.4 ro I z 0.2 O 1E0 1E1 1E2 1E3 1E4 1E5 I ES 1E7 Cycles to failure ▼ CH15 - CH16 • CH17 □ CH15 v CH16 o CH17 Figure 5.49. Normalized S-N fatigue data for materials with 28 percent 0° plies, [±45/0/±45]s layup with D092 and DB 120 fabrics, R=0.1 and 10. R = IO R = 0.1 Material Vr % UCS, MPa bc strain for IO6 cycles, % UTS, MPa br strain for IO6 cycles, % E, GPaU Il I CHl 5 32 -345 0.100 -1.02 309 0.103 0.85 14.8 CHl 6 40 309 0.085 -0.80 360 0.129 0.68 18.5 — — V S CHl 7 48 301 0.079 -0.94 359 0.139 0.40 17.6 O - --------;----------------- ■ T « ‘ j l jO O ^ V mm T W ° 7 ^ ° O ▼ ▼▼ r G —# R = 0 . (solid sym (open sym bo Is) m ■ R = 1C bols) -------1 F i -F H # — i l i m n — i— f - H H ti -------1— 1"H (III -------MH H Il — M -I m u ------- F -I- I I Mi l 4 3.5 ^ 3 I 2.5 I 1.5 S 5 1 0.5 0 1E0 IE I 1E2 1E3 I E4 1E5 1E6 1E7 Cycles to failure ▼ CH15 ■ CH16 • CH17 □ CH15 v CH16 o CH17 I ' m I i — — — — — — I ■I ▼ ▼ ■ T Il ........... V...... s . ° cI — ooe^ v ▼ - R = O1 (solid symbols) •« !■ ° r c P -> R = 10 (open symbols) # -----1- HIH Mil ------1- I- -H-FHI — I I 11 Illl — I I 11 Illl ------1 I I I Illl ------HF -H I IH ------1 - I I I Illl Figure 5.50. Maximum initial fatigue strain data for materials with 28 percent 0° plies, [±45/0/±45]s layup with D092 and DB 120 fabrics, R=0.1 and 10. 114 1.2 % Iw iS 0.8 (Z) E E 0.6 (S E "S 0.4 ro E o 0 . 2 0 R = 10 R = O l Material Vr%UCS,MPa b, strain for IO6 c y c le s , % UTS, MPa br strain for IO6 c y c le s , % E , QPaII — — CH6 4 9 -408 0.100 -0.80 502 0.139 0.50 21.5 CH12 34 -451 0.092 -1.15 398 0.099 0.94 17.4 CHl 4 44 -412 0.081 -1.00 517 0.134 0.75 21.0 -448 0.106 -0.90 0.40 18.5 □ D ^ O O • t IXl i v W T EDO 0jD»X S g ■ O R = 0.1 solid symbc Dpen symbc >ls)........... T T T • R= 10( • I s ) ---------1 I I I HM -------1 I I I Il l l -------1 M I m i -------I l l t H M -------1 I I l l l l l ------- 1 l l l l l l l — I I 11 Il l l 1E0 1E1 1E2 1E3 I E4 1E5 1E6 1E7 Cycles to failure T CH6 ■ CH12 - C H M = CH23 v CH6 nCH12 o CH14 %CH23 Figure 5.51. Normalized S-N fatigue data for materials with 39 percent 0° plies, [±45/0/±45]s layup with D 155 and DB 120 fabrics, R=O l and 10. R = 0.1 (solid symbols) R = 10 (open symbols) Cycles to failure T CH6 ■ CH12 * CH14 % CH23 v CH6 oCH12 o CH14 %CH23 Figure 5.52. Maximum initial fatigue strain data for materials with 39 percent 0° plies, [±45/0/±45]s layup with D155 and DB 120 fabrics, R=0.1 and 10. 115 1.2 I 1 1 2 0.8 -a E I 0.6 CO E I 0-4 CO E I 0.2 0 R = 10 R =0 .1 Material Vr % u c s , MPa b, strain for IO6 cycles, % UTS, MPa br strain for IO6 cycles, % E, GPaSi AA 35 -348 0.081 -0.95 452 0.140 0.50 18.8Il------------------ EJ .. A A3 51 -284 — .... 478 0.140 0.40 25.2 AA4 37 -449 ---- —— 377 0.105 0.67 20.4 O OD OC I r w _ m * * ... T r a — R = 0.1 (solid symt (open symb W Is) » ■ R= 10 ols) ----- M H------ I l l l Illl ----- 1 I I I Illl — I I 11 Illl ----- I-I -H-IMI -----1 I I I Illl ----- 1 I I I IlH -H-FH- 1EO IE I 1E2 1E3 1E4 I ES 1E6 1E7 Cycles to failure ▼ AA ■ AA3 • AA4 □ AA v AA3 o AA4 Figure 5.53. Normalized S-N fatigue data for materials with 50 percent O0 plies, [±45/0/]n layup with stitched triax fabrics, R=0.1 and 10. SE I 2 I 1-5 I ' --- -« 4 __ I__ Il I I — — — —Il4» ! 5 H [] H............... rT * * L . e ..................• I T * e QD I / * OOO R = 0.1 (solid symt (open symt XD I S ) ■ ▼ Il O ols) ■ --- I-H-HFtF----1 I I I Illl — t i l l ini — i n i ini ----I-H-H-FMF----1 I I I Mil ----t i l l Mil 1E0 1E1 ▼ AA I ES 1E6E2 1E3 1E4 Cycles to failure AA3 • AA4 o AA v AA3 o AA4 Figure 5.54. Maximum initial fatigue strain data for materials with 50 percent 0° plies, [±45/0]N layup with triax fabrics, R=0.1 and 10. 116 Cycles to failure Figure 5.55. Normalized S-N fatigue data for materials with 55 to 63 percent 0°plies, R=0.1. Cycles to failure Figure 5.56. Maximum initial fatigue strain data for materials with 55 to 63 percent 0° plies, R=0.1. 117 Figure 5.57 details the million cycle tensile strain data versus the fiber volume fraction for the materials with 19 to 63 percent 0° plies. As the fiber content increases, the million cycle strain falls, except for materials BE, CC, CC2, CC3 and the FF series, which remain almost constant. These materials show a million cycle strain insensitivity over the fiber volume fraction range of 0.36 to 0.45; higher fiber contents have not yet been tested. The tensile (R=0.1) fatigue coefficient, b, versus the fiber volume fraction is shown in Figure 5.58. As the fiber content increases, the tensile fatigue coefficient increases, again except for materials CC, CC2, CC3 and the FF series. The lay-up of these materials are summarized in Table 5.8 and the improved fatigue behavior may be due to the use of a lighter more uniform fabric with less stitching QD100 fabric 0°) and more plies. ..CH23 (mat) 0.4 0.45 Fiber volume fraction n 19% 0's v 24% 0's a 28% 0's a 39% 0's ■ 50% 0's • 55 to 65% 0's Figure 5.57. Million cycle tensile strain data versus fiber volume fraction for materials with 19 to 63 percent 0° plies, R=0.1. 118 Figure 5.59 shows the normalized S-N fatigue data (R = 0.1 and 10) for some of the materials with 72 to 85 percent 0° plies. The material lifetime scatter is similar to the materials with less than 55 percent 0° plies and the compressive fatigue behavior is better than the tensile behavior. The reason for the materials with 55 to 63 percent O0 plies having a less scatter in fatigue (R=0.1 and 10) than all the other materials tested has not been determined. CH23 (mat) o 0.13 % 0.12 ^ 0.11 S/So = 1 - b Log N Fiber volume fraction D 19% 0's v 24% 0's A 28% 0's a 3 9% Q's ■ 50% 0's • 55 to 65% 0's Figure 5.58. Tensile fatigue coefficient, b, versus fiber volume fraction for materials with 19 to 63 percent 0° plies, R=O.I. 119 Table 5.8. Lay-up summaries for materials with 55 to 63 percent 0° plies. Material Vp % Ply Configuration Matrix Fabric Description BB 42 [±45/02/+45]s P O s-A130 (62%), 45's-DB120 CC 39 [±45/02/+45]s P O s-D100 (55%), 45's-DB120 CC2 45 [±45/03/+45]s P O's-D 100 (63%), 45's-DB 120 CC3 45 [0/±45/02/+45]s P O s-D 100 (63%), 45's-DB 120 FFA 38 [±45/0/0/±45]s P O's-D 155 (56%), 45's-DB 120 (44%)FFB 38 [0/±45/0/±45]s P FFC 38 [0/±45/±45/0]s P FFD 38 [0/0/±45/±45]s P FFF 38 [±45/±45/0/0]s P Cycles to failure - DD2 (72% 0's, R=0.1) * DD25 (76% 0's, R=0.1) * Y (85% 0's, R=0.1) • GG (84% 0's, R=O. 1) a DD2 (72% 0's, R=10) ? DD25 (76% 0's, R=IO) a y (85% 0's, R=10) Figure 5.59. Normalized S-N fatigue data for materials with 72 to 85 percent 0° plies. 1 2 0 Effect of R Value Figures 5.60 and 5.61 shows stress and strain S-N data for R values of 0.1, 10, and -1.0 for material DD5P. The compressive one-cycle strength is typically lower than the tensile strength, but the fatigue coefficient, b, is also lower (less fatigue sensitive), so the R = 0.1 and 10 data sets usually cross at some point as the stress decreases. The reversed loading (tension - compression) case, R = -I, tends to follow below the stresses for the lowest of the other curves, being dominated by compression at higher stresses (shorter lifetimes) and tension at lower stresses (longer lifetimes). The corresponding one million cycle maximum initial strain values for R = 0.1, 10, and -1.0 are 1.15%, 1.30%, and 0.62%, respectively. The strain value is usually the lowest for R = -1.0, while the • fatigue coefficient, b, for this case is poorly defined because the failure mode shifts from compression to tension dominated. Thus, these data are markedly nonlinear. Comparison of Materials Figure 5.62 gives the tensile fatigue strain based S-N data for a broad sampling of the database, including both MSU and industry fabricated materials. The results show a very broad range of performance, varying from the best observed fiberglass response (b = 0.10, IO6 cycle e = 1.2%), evident for many materials, to much poorer performance. The one million cycle strain varies down to about 0.4% for the poorest materials, and b increases to about 0.14 for these same materials. The consequences of the poorer materials relative to the best materials are lifetimes of over 100 times shorter and stresses and strains reduced to as low as one-third of the values for typical material DD5 in the 121 ■ C l rr I -S2 1 c F • I■ ■ ■ ■ W i i • •• • W V ■ ■ ■— ■ ■ V ▼ L • * • « * • ■ " . _■) CD 6 CD IAl ----1-I H UH— i 11 mu ----1 HHUl ----1 I I Illtl ----I -H HHl ----1 HHIII ----1- 1-1 Iltll — I I m m — I i t mu 1E0 1E1 1E2 1E3 1E4 1E5 1E6 1E7 1E8 1E9 Cycles to failure - DDSP-R = Ot ▼ DDSP-R = IO - DDSP-R = -I Figure 5.60. Maximum fatigue strain versus cycles for material DD5P, R = 0.1, 10 and-I. 700 600 CLS * 500 2 400 Ijsoo E I 200 roS too 0 1E0 I Et 1E2 1E3 1E4 1E5 1E6 1E7 1E8 1E9 Cycles to failure Figure 5.61. Maximum fatigue stress versus cycles for material DD5P, R = 0.1, 10 and -I. Ii Ii ■ R = 0.1 ▼ R = IO • R = -I I r ■ * I ■ ■ m^w * mm e m W ■ ▼ WV • * ■ ■ ■ I ■ * i ■ * I m m — i t min—I H t-Wf—I I mm—I- I--HfHt—M HIHli---I-FH HH—I 11 mu—i 11inn—i i mm 1 2 2 Figure 5.63 gives a simplified representation of the normalized maximum stress mid-stress range. This materials difference could represent a factor of three in wind turbine blade weight if the entire blade length were tensile fatigue dominated in design (which is unlikely), data in terms of "best" and "worst" normalized S-N performance under tensile loading. While fatigue limits have not been rigorously established, failures have not been observed at maximum stresses below SZS0 = 0.15 in the database, which extends to between IO7 and IO8 cycles for several materials. This figure should not be interpreted to indicate that SZS0 = 0.15 represents a fatigue limit out to any cycle range. Rather, it indicates that even the poorest performing materials (containing significant O0 fibers) do not fail at stresses below this value over the cycle range tested. Materials with few or no fibers in the 0° direction often fail at much lower strains than those of the “worst” materials in Figure 5.62, as discussed earlier, but still with SZSo > 0.15. Figures 5.64, 5.65, and 5.66 give corresponding results for the overall database at R = 10 and -1.0., with the -I data normalized by the compressive strength in Figure 5.65 and the tensile strength in Figure 5.66. There is considerably less variation in fatigue performance between different materials under compressive loading (R = 10), as compared to tensile fatigue (R = 0.1). The compressive fatigue response is actually slightly better than the best tensile fatigue performance, with b values generally in the 0.07 to 0.10 range. The reversed loading performance, as noted earlier, is slightly worse than the lowest (lowest stresses on the S-N curve) of the tensile and compressive fatigue data sets. At worst, the strains under reversed loading are around 0.40% at one million cycles, with the best performance around 0.70%. Table 5.9 compares these values for several materials. 123 3.5 3.0 § 2.5 "S I 2.0 I I 1'5 1 1.0 I l r I N D U S ! 4< - Q T - r M S U - ■ ■ 1A I 5 N a wd _ V A ■ f STV r - r ■ i ,W0 C a . . ----------1 ------ ■ - - -------1—f -H tlH -----1 I I I till -----1 I l UI H — i - H i mi — i i i m u — t I I m u -----1—1-1 FHH — i - i I t i i i i 1E0 I E6 1E8I E1 I E2 1E3 1E4 1E5 C y c l e s t o f a i l u r e Figure 5.62. Tensile fatigue data for various MSU and industrial materials, R = 0.1. Cycles to failure, N Figure 5.63. Extremes of normalized S-N tensile fatigue data (R = 0.1) for fiberglass laminates with at least 25 percent of the fiber in the 0° direction. 124 S/So = 1 - b log N b = 0.07 3 0.3 2 0.2 I E3 1E4 1E Cycles to failure, N Figure 5.64. Normalized compressive fatigue data for standard coupons with 25 percent or greater percent 0° fibers, R=10. S/So - I - b log N b = 0.12 3 0.3 b = 0.18 <5 0.2 Cycles to failure, N Figure 5.65. Reversed loading fatigue data normalized by the compressive strength for materials with 25 percent or greater percent 0° fibers, R = -I. 125 S/So = I - b log N 2 0 .3 Cycles to failure, N Figure 5.66. reversed loading fatigue data normalized by the tensile strength for materials with 25 percent or greater 0° fibers, R = -I. Table 5.9. Summary of fatigue results: tensile (R = 0.1), compressive (R= 10) and reversed loading (R = - I)._____________________________________________ /0 H p R= 10 R = -I Material vF % % 0° bT strain for IO6 cycles, % be strain for IO6 cycles, % bR strain for IO6 cycles, % E, GPa H 37 70 0.114 0.52 0.100 -0.72 0.136 0.45 24.0 N 38 50 0.140 0.46 0.096 -0.70 0.135 0.30 19.3 P 40 48 0.134 0.48 0.099 -0.66 0.133 0.42 22.5 AA 35 50 0.140 0.50 0.081 -0.95 0.139 0.40 18.8 EEAV 49 70 0.100 0.75 0.077 -1.30 0.068 0.70 28.2 DD4 48 72 0.136 0.55 — — 0.123 0.50 31.0 DD5E 36 72 0.110 1.20 0.056 -1.42 0.123 0.66 23.6 DD5P 36 72 0.101 1.16 0.072 -1.35 0.135 0.62 24.2 DD5V2 35 72 0.102 1.39 0.064 -1.66 0.117 0.68 213 DDll 31 72 0.100 1.20 0.090 -0.70 0.095 0.60 20.0 45D155* 38 0 0.109 0.40 0.089 -0.65 0.148 0.25 9.79 ^Material 45D155 was a ±45° composite 126 The stitched fabrics used in this study were expected to behave more like uniform layer composites common in materials such as prepreg laminates, which show a fatigue coefficient, b, of about 0.10 at R=0.1 [60]. However, early results in this study with the Triax fabrics showed trends following the “worst” behavior in Figure 5.63 [3], The Triax fabrics vary in detail, but have ±45° strands stitched against the 0° strands. Detailed experimental study of these materials showed that the 0° strands failed at these stitch points [3]. A very detailed finite element model for the individual strands with cracked matrix found the apparent cause of this problem: if there is no layer of resin matrix between the strands, matrix cracks along the 45° strands will produce significant stress concentrations in the 0° load-bearing strands. Results reported in References 3, 4, and 58 showed that the Triax reinforced materials failed under tensile fatigue loading shortly after the ±45° layers failed, giving it the worst behavior. In general, it is expected that a composite will be designed to fail in a “fiber dominated” mode, where the trend, b, is the same as for the 0° material alone. Here, the combination of glass fiber properties and tightly stitched fabrics resulted in composite failure soon after matrix failure, a behavior which is “matrix dominated”. Since matrix failure in 45° layers occurred at lower strains than for fiber failure, this produced poor composite performance in tensile fatigue. Unfortunately, this matrix dominated response is not limited to Triax reinforcements. Additional tests [7] have shown similar behavior under some conditions with separate 0° and ±45° layers, and even with 0° unidirectional stitched fabric composites without any ±45° material. Figure 5.67 shows the database trends for several materials at R=0.1, but broken into several groups. The top group (denoted with the solid triangles in the figure) behaves like the “best” materials, with b close to 0.1. The middle 127 group (denoted by an open triangle) behaves like the “worst” materials, with b close to 0.14. The lower group of materials (denoted by a solid square) are ±45 laminates containing no 0° layers. Just as determined for Triax laminates earlier, Figure 5.67 indicates that the poorly performing laminates with 0° layers.fail close to the “worst” line in Figure 5.62, because they fail shortly after the ±45° layers reach their failure condition. Thus, the “worst” line in Figure 5.62 appears to originate from matrix failure in the ±45° layers, where present. Unidirectional laminates with only 0° layers which show “worst” behavior (at high Vf) appear to fail shortly after the fabric stitching debonds. In general, the trends with Vf for laminates with 0° and ±45° material are similar to those for the unidirectional materials (Figures 5.33 and 5.34), but the transitions to greater fatigue sensitivity occur at slightly lower values of Vf when ±45 ° material is present. Tensile S-N data for the DD series of structural materials (72% 0°, 28% ±45°) at various overall fiber contents are given in Figure 5.68. The trends are clear: at fiber volume fractions below 0.42 the data follow the “best” line in Figure 5.62, b = 0.10; at higher fiber contents the data approach the “worst” condition, b = 0.14. Thus, there is a transition with increasing fiber content from “best” to “worst” fiberglass behavior in tensile fatigue. The strains at IO6 cycles shown in the insert on Figure 5.68, follow a similar trend, from around 1.0 to 1.2% at lower fiber content to 0.6 to 0.7% at higher fiber content. Even though the increasing fiber content raises the static modulus and ultimate tensile strength, the fatigue performance deteriorates significantly on either a normalized (b) or absolute (strain at IO6 cycles) basis. Figure 5.69 shows the tensile and compressive fatigue coefficient, b, versus the fiber volume fraction for most of the DD series with D155 stitched fabrics and A130 woven fabrics. 128 The data are also interesting when plotted as the million-cycle initial maximum strain which can be withstood in tensile fatigue. Figure 5.70 gives the million-cycle strain plotted against the percent 0° layers for low and high fiber volume fraction ranges. At high fiber contents, where b approaches the “worst” value close to 0.14, the million-cycle strain is about 0.5% for the ±45° laminates alone, and for all laminates containing 0° and ±45° layers, rising slightly for the pure unidirectional (0°) laminates. This is consistent with the view that the “worst” behavior corresponds to laminate failure when the ±45° layers or matrix regions fail (all layers are at the same strain). This is matrix-dominated behavior, since the laminate fails shortly after matrix cracks form in the ±45° layers. Compression and reversed loading trends are detailed in Reference 2. 2.6 2.4 2.2 2 I 1-6 I 14 I 1.2 I i a o s 5 0.6 0.4 0.2 0 -I-M-I 1EO ▲—A I M Mill “ T 1: x 4, -H- A i , 4&A -H- A t Material Vf ■ [±45]s 0.28 - 0.49 A [0/±45/0]s 0.31 - 0.42 A [0/±45/0]s 0.43 - 0.62 - A £ AfeP i ' * / -I-I-I till I I I mu i i i mu 1E3 1E4 1 ES Cycles to failure 1E6 1 ES Figure 5.67. Strain fatigue data for [±45]s and [0/±45/0]s materials, R=0.1. 129 S/So = I - b log N Tensile strength, So, MPa strain for IO6 cycles, % Material b = 0.10 W 0.8 b = 0.14 DD2 ▲ DD4 # DD5 ▼ DDG X DD7 I--Hmnl I i i i im| -M -MHlI I I I H ill Cycles to failure, N Figure 5.68. Effect of fiber content on the normalized S-N data, R=0.1, for DD materials [0/±45/0]s. S/So = I - b Log N ■DD7----- tension (R = 0.1) DDl 3 U 0.12 DDl 3DD5P DDll compression (R= 10) DD5P 0.42 0.46 Fiber volume fraction Figure 5.69. Fiber content versus fatigue sensitivity coefficient, b, for DD materials. 130 1.4 1.2 SR i 1 s- % 0.8 I 0.6 I I 04 C 0.2 0 ■------- : ■ ■ ■ I■■ ▼ ▼ ▼ ▼ ▼ ▼ ▼ ■ Vp = 0.3 - 0.4 ▼ Vp = 0.45 - 0.55 I All ±45 Percent 0 plies 80 90 100 AIIO0 Figure 5.70. Initial strain for IO6 cycles (R = 0.1) versus percent 0° plies, D155, CH and DD materials. Failure Modes Figures 5.71 to 5.83 show photographs of typical failed specimens for a variety of materials and loading conditions. Failure modes for all tests in the database were compared, and, for the most part, few strong trends were evident. This section describes the main differences seen in failure modes. Testing of unidirectional materials of fiberglass in tensile fatigue is difficult, as noted earlier. Figure 5.71 compares failures of unidirectional Material A tested in the standard tabbed configuration and the tapered thickness configuration (Figure 2.6). The failure is much improved for the tapered specimen, with the brooming-type of separation as compared with failure under the tabs for the standard specimen. However, differences in the tensile fatigue results for the two cases were not significant. Figures 5.72 to5.74 131 show typical failures for unidirectional RTM materials with two fabrics and low vs high fiber content. The A130 fabric failures show a clear association with the bead over which they are woven, particularly in compression. The D155 fabric based materials show no effect of the stitching in the failure patterns; axial splitting is evident at high fiber content in compression. Figures 5.76 through 5.81 show materials varying from low to high percent 0° layers at different fiber contents. The 0° layers include both woven (A130) and stitched (D155) fabrics. Other weights of these types of fabric show similar failures. The tensile static and fatigue failures become less localized, with more specimen-long brooming as the fiber content increases. The bead effects evident in the unidirectional Al 30 materials are also evident when ±45° layers are added. Cracking and delamination at tapered-width specimen shoulders (described in Figure 4.6) is more prominent, even at low cycles, as the percent of 0° layers increases. The typical structural materials such as DD5 (Figure 5.80 and 5.81) show severe shoulder delamination, but failure zones (failed 0° strands) can be seen in the gage section prior to failure at low stresses. At high fiber contents (Figure 5.82), the failures tend to localize in the gage section, with less shoulder damage. The D155 fabric with stitching removed (Figure 5.83) behaves similarly. Shoulder damage starts as splits parallel to the 0° fibers at the break between cut and uncut 0° material, with interply delamination then developing at higher loads or cycles. Specimens which fail away from the shoulder area are preferred, since there is no possible effect of specimen geometry on the test. However, for many materials, this has been impossible to achieve for all specimens in a series of S-N tests. 132 Figure 5.71. Comparison of tensile fatigue test coupons, unidirectional Material A (Vf = 30%). Standard test coupon (top) and thickness tapered coupon (bottom). Figure 5.72. Unidirectional materials based on A130 fabric (Material A130C, Vf = 35%). From top to bottom: static tensile coupon; tensile fatigue (R = 0.1, 345 MPa); static compression, and compression fatigue (R= 10, 276 MPa) 133 Figure 5.73. Unidirectional low fiber content materials based on D155 fabric (Material D155B, Vf = 39%). Static coupon (top), tensile fatigue R = 0.1, 345 MPa (bottom). Figure 5.74. Unidirectional high fiber content materials based on D155 fabric (Material D155G, Vp = 59%). From top to bottom: tensile fatigue, R = 0.1 coupons tested at 552 and 276 MPa; static compression and compression fatigue (R= 10, 483 MPa). 134 Figure 5.75. Material GG (VF = 40%) with 84% O0 in the loading direction showing heavy brooming upon failure, tensile fatigue (R = 0.1, 345 MPa). Figure 5.76. Material CH9, (Vf = 49%, all ±45 layers). From top to bottom: static tensile coupon, tensile fatigue, (R = 0.1, 86 MPa); static compression and compression fatigue (R= 10, 86 MPa). 135 Figure 5.77. Low fiber content, low percent 0’s. Material CH3 (VF = 36%, 24% 0's). Static tension coupon (top) and tensile fatigue (R = 0.1, 72 MPa). Figure 5.78. High fiber content, low percent 0’s. Material CH13 (VF = 48%, 24% 0's). Static tensile coupon (top) and tensile fatigue (R = 0.1, 172 MPa). 136 Figure 5.79.Moderate fiber content and percent 0’s. Material CH14 (VF = 44%, 39% 0's). From top to bottom: static tensile coupon; tensile fatigue (R = 0.1 172 MPa); static compression; and compression fatigue (R= 10,241 MPa). Figure 5.80. Standard structural material at low fiber content, 72% 0’s. From top to bottom: Material DDl I (A130 fabric 0’s, Vf = 31%); tensile fatigue (R = 0.1,276 MPa); compression fatigue (R= 10, 172 MPa); and Material DD6 (D155 fabric 0’s, Vf = 31%); tensile fatigue (R = 0.1,276 MPa); and compression fatigue (R = 10, 379 MPa). 137 Figure 5.81. Standard structural material with 72% O’s, (Material DD5, Vf = 38%). From top to bottom: static tension, tension fatigue (R = 0.1) 310 MPa and 276 MPa. Figure 5.82. Standard structural material at moderate fiber content, Material DD12 (71% A130 0° fabric, Vf = 43%), (top) tensile fatigue (R = 0.1, 241 MPa) and DD5 (72% D155 0° fabric, Vf = 38%) tensile fatigue (R = 0.1, 345 MPa). 138 Figure 5.83. Standard structural materials at higher fiber content, from top to bottom: Material DD13 (71% A l30 fabric, Vf = 50%), tensile fatigue (R = 0.1, 345 MPa); Material DD7 (72% D155 fabric, Vf = 54%), tensile fatigue (R = 0.1, 207 MPa); Material DD9 (72% D155 fabric, stitching removed, Vf = 54%), tensile fatigue (R = 0.1, 207 MPa); Material DD7 static compression, and compression fatigue (R= 10, 345 MPa). Compressive failures are very similar for static and fatigue tests, with a symmetrical splaying-out of the layers from the unconstrained specimen surfaces. Little damage is evident in the compressive specimens prior to sudden failure. The A l30 fabric based materials often show independent delamination of strands at failure in compression (Figure 5.80). The thermoplastic-coated bead over which strands are woven is evident in this figure. Fabric Architecture Effects These results indicate a similar trend for all stranded E-glass fabric reinforced 139 laminates toward a steeper S-N curve (higher b) as the fiber content increases, with the presence of off-axis (± 45°) layers shifting this transition to lower fiber contents. Fabrics with an effectively high fiber content inherent in the fabric construction, Triax materials with 0° and ±45° strands stitched tightly together, show poor fatigue resistance over the entire fiber content range studied. The problem of finding a fabric for structural areas with good fatigue properties, good compressive strength, and a high percentage of warp unidirectionals has led in several directions, but has not been solved at this writing. One type of fabric available from Owens Coming Knytex is warp unidirectionals similar to D155, produced by stitching strands to a light mat material (CM1701). D155 in weft unidirectional provides a good balance of properties at fiber contents below 42 percent, but is not produced as a warp unidirectional. The CM 1701 fabric was tested at 38 percent fiber volume fraction with the results showing disappointing tensile (R=OT) fatigue results, with b = 0.126 and the million cycle strain at 0.64 percent. Figures 5.84, 5.85 and 5.86 show photographs of the fabrics used in this study. Figure 5.84 shows the unidirectional stitches and adhesively bonded fabrics. The D072, D092, D155 and UC1018V fabrics had “good” fatigue behaviors (R = 0.1 and 10) up to a fiber volume fraction of approximately 0.40. At higher fiber contents the fatigue performance shifted towards the “worst” behavior shown in Figure 5.63. The AlOlO and CM 170IA fabrics performed below expectations and provided poor fatigue behavior, especially the AlOlO fabric with loose stitching. Microscope specimens of these two materials revealed large and continuous matrix cracks around the stitching. It is believed 140 that the stitching provided a path for the cracks to develop and easily debond the fiber strands causing delamination and eventual failure. Figure 5.85 details the woven unidirectional fabrics and three ±45° fabrics which were tested. The A060 fabric was poorly constructed with a weaving thread and thermoplastic bead which was more suited for heavier fabrics. The right hand side of the A060 fabric photograph shows thermoplastic adhesive from other beads on the fabric roll. This thermoplastic bead material did not bond well to the matrix materials and was a starter location for cracking. The A130 and A260 fabrics performed similar to the D155 stitched fabric in tension fatigue (R=0.1), but due to the pre-buckled geometry, had a ultimate compressive strength of less than 50 percent of the D155 fabrics. The DB 120 fabric provided a higher static strength for a specific fiber content than the other fabrics. The DBM1204B fabric (not shown) was the DB 120 stitched to a glass mat, which showed poor fatigue behavior as the other fabrics containing a mat. Figure 5.86 shows the two Triax fabrics, front and back faces. The CDB-200 fabric showed consistently poor fatigue performance at all fiber contents, while the TV- 3400 showed better fatigue performance. The TV-3400 fabric had less stitching and had a weight which was twice as heavy as the CDB-200 fabric. Additional tests on higher fiber volumes need to be performed on this Triax. 141 13 mm X 13 mm photographs Figure 5.84. Photographs of unidirectional stitched and adhesively bonded fabrics. 142 Figure 5.85. Photographs of woven unidirectional and stitched ±45 fabrics. 143 O0 face CDB-200 Triax ± 4 5 ° face O0 face TV-3400 Triax ± 4 5 ° face 25 mm X 25 mm photographs Figure 5.86. Photographs of stitched Triax fabrics. 144 Conclusions The tensile fatigue (R = 0.1) performance of glass fibers and unidirectional strands is a property inherent in the fiber reinforcement. Smaller fiber strands gave the best tensile fatigue performance. The high cycle strand fatigue data suggest a leveling off of the S-N trend between IO8 and IO9 cycles, but more high cycle data are needed to establish this observation. No clear fatigue limit was observed. With fabrics containing stitching or weaving, this fatigue performance decreases to a fatigue coefficient of approximately 0.10 for lower fiber volume fractions, with a significant increase in sensitivity to around 0.14 for high fiber contents, where fatigue appears to be associated with stitching and matrix cracking. The Triax material, based on CDB200 fabric with 0° and ±45° layers stitched together, shows poor performance even at low overall fiber contents; similar data for several other Triax materials are given in References 4 and 5, and in the database. The DD materials, with separate 0° and ±45° layers, show a transition from good to poor resistance as the fiber content increases, with the transition centered around 42 percent fiber by volume; this transition is at a slightly lower fiber content than with all 0° materials. When the stitching is manually removed from the D155, 0° fabric, the trend to increasing b with fiber content is shifted to still higher fiber contents, so that good fatigue resistance is now observed above 50 percent fiber by volume. The D155 materials with stitching removed are difficult to handle, and show fiber wash problems during matrix infiltration. Literature values [60, 61] for E-glass/epoxy prepreg laminates with a very uniform distribution of fibers in each layer show a b-value close to 0.10 at 50 to 60 145 percent fiber by volume, demonstrating that much of the fatigue problem in tension is related to the stranded fabrics. It has been reported consistently in the course of this study [3, 4, 7] and in the European database [58] that changes in the matrix material have minimal effects on the static and fatigue properties of standard coupons. This has been explored under very well controlled conditions with the RTM process for materials DD5E, DD5P, DD5V, and other ±45° and 90° composites for epoxy, polyester, and vinyl ester matrices at the same fiber content and with other parameters held constant. All the data suggests that there is no significant difference in the fatigue performance of these composites using different matrix materials under dry, room temperature conditions. The main matrix effects occur in delamination resistance and environmental resistance, as reported in Reference 17. 146 CHAPTER 6 BALANCED ANGLE PLY LAMINATES Background Information To reduce the number of design variables, plies in most composites are orientated at either 0°, 90° or ±45°; however, other orientations may provide optimum properties in some applications. Furthermore, the ±45° fabrics used in this study had very poorly controlled orientation due to inaccuracies in the original fabric, or fiber movement either in handling or during the resin transfer molding process. Thus, a study of the effects of orientation on fatigue properties was performed. The initial study concentrated on balanced angle ply composites with angles of ±30°, ±40°, ±45°, ±50° and ±60°, which was later expanded to include ±10°, ±20°, ±70°, ±80° and 90° laminates. Most of the materials in the database with ±45° plies used the Owens Corning Knytex DB 120 fabric. The DB 120 fabric, as well as the heavier DB240 fabric, has fiber tows that are loosely stitched together and can be easily stretched during handling and composite manufacture, which alters the fiber orientation angles. The ±45° fiber orientation of the fabric could be easily changed by approximately ±6 ° to ±10° by handling (fabric unrolling). The angle orientation change from ±45° had been noticed in all the MSU manufactured laminates and the industrial supplied materials included in the DOE/MSU composite material database [2], The actual ply angles of the 0°/±45° and 147 ±45° laminates listed in the database were measured following matrix digestion, and are summarized in Table 6.1. Most of the industrial materials involved an Owens Corning triaxial fabric (07±45°), CDB200, which is a 0° fabric (D092), stitched to a ±45° fabric (DB 120). Table 6.1. Measured angles of 0/±45 and ±45 materials listed in the database. Material Measured Angles Average Measured ± Angles F [-55/48/0/-53/48/0/-49/47/0/-50/53/0] 497-52° G [0/-50/50/0/-50/51 /0/-50/52/0/-50/53] 527-50° H [45/-43/0/50/-47/0/43/-47/0/0/49/-47/0/50/-46/0/44/-48] 477-46° J [0/47/-47/0/50/-46/0/45/-47/45/-46/0/46/-45/0/51 /-42/0] 477-46° M [43/-49/0/43/-43/0/45/-46/0/37/-44/0] 427-46° N [42/-49/0/42/-50/0/42/-51/0/42/-48/0] 427-50° P [0/45/-42/Mat/0/0/Mat/40/-42/0] 437-42° R [0/33/-42/0/37/-39/0/49/-34/0/37/-42] 397-39° T [0/-53/54/0/-53/53/0/-54/53/0/-52/51 ] 537-53° U [0/42/-41 /0/42/-42/0/43/-41 /0/42/-42] 427-42° V [0/45/-46/0/45/-44/0/45/-45/0/46/-45] 457-45° W [55/-48/0/55/-48/0/56/-48/0/55/-48/0] 557-48° X [0/0/M/-51/50/0/0] 507-51° Y [0/0/M/35/-53/0/0] 357-53° DB 120 [42/-51] 427-51° DB240 [42/-51] 427-51° DB400 [40/-51 ] 407-51° 148 It was very difficult to prevent the original fiber orientations from changing during typical manufacturing operations. Careful fabric cutting, handling and RTM injection limited the maximum fiber misalignment of the DB 120 fabric to approximately -3 ° deviation from the +45° ply and an average of +6° from the -45° ply giving an overall fabric orientation of [+427-51°]. This was the typical fiber orientation found in the MSU manufactured materials listed in the database dealing with the ±45° Knytex fabrics. The construction of larger, non-flat or more complex composite shapes would cause further . difficulty with fabric handling during construction. Part of the fiber orientation problem is the physical tension force required as the fabric is spooled on and off of the fabric storage roll. This tension, and the loose structural stitching, allows for easier fiber reorientation, with biasing towards the fabric rolling (tension) direction. It should be noted that in high technology applications (prepreg or filament winding) such as aerospace, a fiber orientation tolerance of ±0.5° to ±1 ° is common. Although this study involved balanced lay-ups, with equal numbers of +0 and -0 plies, more research is required to study the effects of unbalanced lay-ups, which would better represent the actual composites. The balanced angle-ply composites were manufactured using six plies of the Owens Coming, Knytex D155 fabric and the CoRezyn 63-AX-051 orthothalic polyester resin. The D155 unidirectional fabric was easily manipulated into the various ply angles and the general D155 zero degree properties were well understood and documented in the database. A balanced laminate (±0°)N, rather than a balanced symmetric laminate (±0°)s was used to more accurately represent the MSU manufactured materials listed in the 149 database. A symmetric eight-ply laminate would have two plies with the same orientation in the center. The double center ply would matrix crack in both plies at once creating a matrix crack two plies in width, compared with the single-ply cracks in typical laminates. Thus, the unsymmetric case was chosen to avoid larger matrix cracks. General angle-ply data are summarized in the database and are also shown in Table 6.2, for the static strength, longitudinal modulus and major Poisson’s ratio, which are values that could be calculated by standard laminate analysis techniques. Very limited angle ply fatigue data (R = OT) are available elsewhere [61-64], with all these data being at a high enough testing frequency (17 to 30 Hz) which may have forced thermal, rather Table 6.2. Properties of MSU manufactured (RTM) fiberglass materials with balanced angle plies. R=IO R = OT Angle Vf % UCS MPa ^ c strain for IO6 cycles, % UTS, MPa bT strain for IO6 cycles, % E, GPa V XY [0]5 39 -653 0.077 -1.10 854 0.093 1.12 31.5 032 [±10o]3 38 -384 — 277 0.068 0.62 27.9 0.38 [±20° ]3 39 -287 — 268 0.079 0.55 24.2 0.56 [±30°]3 40 -176 0.065 -0.48 186 0.098 0.43 17.7 0.67 [±40o]3 40 -132 0.095 -0.50 144 0.109 0.41 11.4 0.62 [±45% 38 -138 0.089 -0.65 107 0.109 0.40 9.79 0.57 [±50% 39 -138 0.085 -0.78 65 0.092 0.38 8.62 0.51 [±60% 40 -141 0.081 -0.94 37 0.074 0.25 7.65 0.35 [±70% 40 -136 — 27 0.076 0.19 7.24 0.21 [±80% 38 -153 — 26 0.087 0.17 7.16 OTO [±90% 38 -123 0.062 -1.07 26 0.081 0.19 7.24 009 All R = 10 test coupons were 25 mm wide anc had a 13 mm gage length. 150 than mechanical fatigue failures. Other available data are limited to only ±45° angles [65, 66], again with most of the data being potential thermal failures. Reference [6] reported R = 0.1 tension fatigue tests on ±45° laminates at 6 Hz. A few high stress cycled coupons in this reference were probably thermal influenced, but the rest of the lower stressed data appear consistent with the database trends. The European FACT Database has a few dozen fatigue data points for ±10°, ±30° and ±45° at various R values [59] and different matrix materials, but not enough data are available to reach any general conclusions about trends. U Testing Methods The testing of composites with off-axis plies involves two associated problems with the composite coupon geometry: the width and gage length. The coupon width part of the problem involves interlaminar stresses, specifically txz, for [+0/-0] ply laminates under uniaxial tension at the free edges, which can initiate cracks and delaminations that will propagate inward, towards the coupon center, until the coupon fails. Literature [67 to 75] indicates that the high interlaminar stresses (Tx z , t x y , o z z ) could be treated as an edge effect and that the magnitude of these stresses reduces to laminate theory predicted values within one to two composite thicknesses away from the edges. Reference 76 reported that the failure of laminates with ply orientations less than approximately 35° to 40° is initiated at the free edges as a result of high interlaminar shear strains, but the failure of laminates with angles greater than approximately 40° were not sensitive to test coupon edge effects. A good discussion of edge effect stresses can be found in reference 75. The 151 effect of test coupon width was not studied and the width was kept constant, 25 mm, for all the static and fatigue tests. Testing problems associated with the coupon gage length deal with restricting the fibers from rotating as the laminate is stressed. If the gage length is too short, the fibers will be continuously clamped at both ends of the coupon, which increases the internal stresses in the composite [69, 77, 78] and decreases the apparent strength and fatigue life. This was shown in the initial series of ±10° test coupons in the database which had a 100 mm gage length (fibers at both ends were clamped) that averaged 5,500 fatigue cycles at a maximum stress of 172 MPa and R = 0.1. When the gage length was increased to 160 mm, which prevented fibers from being clamped at both ends, the average number of cycles to failure increased to 185,000 cycles at the same stress level and R value. A listing of the gage lengths used in this study is shown in Table 6.3. The compression tests, in order to prevent buckling, required a short gage length which prevented the fiber ends from being free for all angles except the ±70°, ±80°and 90“coupons. In this study, all compression tests used the same 25 mm wide test coupon with a gage length of 13 mm. These results may not be representative of larger test coupons or structures. Table 6.3. Tension and compression test coupon gage lengths. Angle Tensile gage length, mm Compressive gage length, mm ±10° ' 160 and 100 13 mm ±20° to 90 ° 100 152 Results and Discussion The tensile stress-strain diagrams are shown in Figures 6.1 through 6.3 for the angle ply laminates. For the tensile strain values listed in these figures, a clip-on extensometer was used during the tests. Figure 6.1 shows the tensile behavior of the ±10°, ±20°, ±30°, and ±33° laminates. The ±10° and ±20° laminates show linear behavior to failure (brittle behavior), failing when the first matrix crack appears. The ±30° laminates start to show some non-linear behavior as the specimen remains intact with matrix cracks in all plies until sufficient delamination occurs to cause complete separation. The ±33° laminate was tested to better define the angular region where the more nonlinear material behavior begins. Figure 6.2 shows the tensile stress strain behavior of the ±40°, ±45°, and ±50° laminates. All three of these laminates showed extensive non-linear behavior as lamina cracking and delaminations formed and grew until coupon failure. It should be noted that the neat polyester matrix had a tensile strain to failure of only 2%. Reference 62 determined that the onset of damage in the ±45° laminates was due to lamina cracking and not interlaminar shear, as was the case found with the ±10°to ±30° laminates. The ±45° laminate, after onset of cracking, continues to sustain load and continued to form cracks all over the coupon until interlaminar crack growth started and continued until the final coupon failure. Figure 6.3 details the stress-strain behavior of the ±60°, ±70°, ±80°, and 90° laminates, which showed little non-linear behavior and all had a strain to failure of less than 0.6%, which was much less than the failure strain of the neat polyester matrix. This weak behavior is associated with stress concentrations around the fibers, and voids, which 153 L ±20 5 200 C 100 Tensile strain, % Figure 6.1. Tensile stress - strain curves for balanced ±10°, ±20°, ±30°, and ±33° angle ply laminates (13155 fabric, Vf = 0.39). ro 120 Tensile strain, % Figure 6.2. Tensile stress - strain curves for balanced ±40°, ±45°, and ±50° angle ply laminates (D155 fabric, Vf = 0.39). 154 O 0.1 0.2 0.3 0.4 0.5 0.6 0.7 Tensile strain, % Figure 6.3. Tensile stress - strain curves for balanced ±60°, ±70°, ±80° and 90° angle ply laminates (D155 fabric, Vf = 0.39). lower the transverse composite strength and strain to failure relative to the neat resin [79]. Figure 6.4 summarizes the average tensile static failure strain versus laminate ply angle. The strain to failure peaked with the ±45° laminate which could be classified as having a ductile material behavior, while the other laminates outside of the ±35° to ±50° range resemble brittle materials. Except for the overall magnitude of strain to failure, this figure is consistent with the one generated by Reference 62. Compression stress-strain diagrams were generated for these laminates using an 18 mm gage length with bonded back-to-back strain gages (BLH FAE-25-35-S13EL-G) which had a 6.35 mm strain grid gage length. The longer coupon gage length was necessary to allow for the placement of the strain gages far enough away from the influence of the gripped coupon ends. The angle ply test coupon widths averaged 25.37 155 mm (S.D.= 0.21 mm) and the thickness averaged 3.08 mm (S.D.= 0.08 mm) for all of the coupons shown in the compression stress-strain diagrams. The stress-strain diagrams are truncated where the strain gages bifurcated, which was immediately followed by coupon failure. Balanced ply angle, degrees Figure 6.4. Ultimate tensile failure strain versus balanced ply angle. The compression stress strain diagrams for ±10°, ±20°, ±30°, and ±40° are shown in Figure 6.5. As was the case in the tensile curves, the compressive ±10° and ±20° coupons show little non-linear behavior, and the ±30° and ±40° curves show an increasing amount of non-linear behavior. Since both strain gages are indicating the same strain, it must be inferred that the coupon, under the axial compressive stress, is barreling outward, rather than buckling to produce the nonlinear stress-strain behavior shown. This 156 same behavior is seen in Figure 6.6 with the ±50°, ±60°, ±70°, ±80°, and 90° laminates. The strain to failure and amount of non-linear behavior decreases as the angle is increased to 90°, as the mode of failure changes from barrelling to through-thickness shearing. The average calculated compressive strength versus ply angle is listed in Table 6.2 and the ultimate strain is shown in Figure 6.7. The minimum failure strain occurs at approximately ±30° while the maximum is at 0° and ±80°. 9 = 3 5 0 % 3 0 0 Absolute compressive strain, % Figure 6.5. Compressive stress - strain curves for balanced ±10°, ±20°, ±30° and ±40° angle ply laminates (13155 fabric, Vf = 0.39, 25 mm test coupon width with a 18 mm gage length and unsupported edges). 157 > 8 0 9 r 6 0 ^ 20 1 1 . 5 2 2 . 5 Absolute compressive strain, % Figure 6.6. Compressive stress - strain curves for balanced ±50°, ±60°, ±70° and 90° angle ply laminates (D155 fabric, Vf = 0.39, 25 mm test coupon width with a 18 mm gage length and unsupported faces). - i 0 . 5 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 Balanced ply angle, degrees Figure 6.7. Calculated average ultimate compressive failure strain versus ply angle. 158 Laminate Analysis Predicted Properties From the generated stress-strain diagrams, the load-direction modulus (Ex) was calculated and is shown in Figure 6.8 along with the laminate theory predicted values. These laminate theory calculations, as well as subsequent laminate analysis, used the property values listed in Table 6.4, which were taken from the database [2] and adjusted for fiber volume content, 0.39 versus the listed 0.45 using the formulae listed in the database. At least one coupon from each angle lay-up was tested with a 0790° strain gage to measure the major Poisson’s ratio (Uxy) which is shown with the predicted values in Figure 6.9. The predicted Poisson’s ratios fall a little lower than of the measured . values, which was the same result found in reference 22. (Reference 80 stated that the predicted value of the major Poisson’s ratio is critically dependant on the value of the shear modulus used in the calculations and was probably the source of the variability seen.) Since only one test coupon per angle was tested, the variability of this parameter is unknown. The equations used a predicted shear modulus calculated from measured values using simulated shear tests (ASTM D3518) and Iosipescu V-notched shear coupons (ASTM D5379) reported in the database, and the variability of the measured value is probably the source of the over-prediction. The calculated value of the shear modulus (Gxy) versus the ply angle is shown in Figure 6.10 for the angle ply laminates. As expected, the maximum shear modulus occurs at ±45°. Figure 6.11 shows the laminate analysis of the longitudinal stress (Oxx), the transverse stress ( o Y Y ) and the in-plane shear stress ( T x y ) versus ply angle. All these stresses have been normalized with respect to the average tensile stress (ox) in the 159 Exx Laminate theory Database values Balanced ply angle, degrees Figure 6.8. Longitudinal elastic modulus versus laminate theory predicted values (13155 fabric, Vf = 0.39). Table 6.4. Ply properties used in the laminate theory analysis (static) and values used for million cycle fatigue predictions adjusted to a fiber volume fraction of 0.39. Property Static values IO6 cycle fatigue values Longitudinal Modulus, (E11) 31.5 GPa 31.5 GPa Transverse Modulus, (E22) 7.42 GPa 7.42 GPa Shear Modulus, (G12) 3.53 GPa 3.53 GPa Major Poisson’s Ratio, (U12) 0.317 0.317 Ultimate Longitudinal Tensile Strain, (ULTS11) 2.71% 1.12% Ultimate Transverse Tensile Strain, (UTTS22) 0.37% 0.19% Ultimate Tensile Shear Strain, (UTSS12) 2.38% 0.91% Ultimate Longitudinal Compressive Strain, (ULCS11) -2.07 % -1.10% Ultimate Transverse Compressive Strain, (UTCS22) -1.67 % -1.07% Ultimate Compressive Shear Strain, (UCSS12) -2.38% -0.91 % 3 j § B # ~ ' 160 -S 0.5 Database values U x y Laminate theory Balanced ply angle, degrees Figure 6.9. Major Poisson’s ratio versus laminate theory predicted values (D155 fabric, Vf = 0.39). Gxy Laminate theory. Balanced ply angle, degrees Figure 6.10. Calculated shear modulus versus balanced ply angle (D155 fabric, Vf = 0.39). 161 x 14 & 1.2 L:<0 § 0.6 1 J S 2 1 - 0.2 ^ -0 .4 I -0.6 OT - 0.8 0 .4 0.2 0 Oy Y 0 XX X Cty y \ -— X TXY XY O x x S / \ . X Z ... O — Xtt-T O x x J 0 I T>CY — I— i -3 0 -10 10 30 Ply angle, degrees Figure 6.11. In - plane laminate stresses versus balanced ply angle (±[6]3 laminate with D155 fabric, Vf = 0.39). X-direction. Interesting observations of these stresses include: the maximum longitudinal stress is equal to 1.21 (ox) at 28°; the transverse stress has a minimum stress of -0.0046 (ox) at 20° and -0.057 (ox) at -25°, which is due to Possion contraction; and the shear stresses have a maximum and minimum value of ±0.539 (ox) at ±52°. There is also no tensile strain perpendicular to the fibers for fiber orientations less than ±28°, which is also the angle at which the longitudinal tensile stress starts to decrease. As expected, the magnitude of the shear stress is exactly ±0.500 (ox) at ±45° and is independent of the material type. Using laminate analysis to predict the tensile and compressive strength of a laminate requires accurate strengths in the 0° and 90° directions of the plies. With these ply strength data to work from, the maximum strain failure criterion, maximum stress failure criterion or the quadratic failure criterion can be used to predict the strengths of the angle ply laminates. A more detailed discussion of these commonly used criteria can be found in Reference 75; the criteria are summarized in Equations 6.1 to 6.3. 162 Maximum Stress Failure Criterion O1,, oy > a FAILURE ^FAILURE cos20 0TU . sin20 xLTU x FAILURE sin0COS0 Maximum Strain Failure Criterion G T I t COS2O-V^ Sin2O 6.1 - Sin2O-v _ Cos2O' ''LTU x FAILURE SHlOcOsO Quadratic Failure Criterion {^ FAILURE* F\ 0LU + ^ 2°TU+^ 110 TO2 +^ l 2°TU~ ~ ^ ’ w^ re F=—+J- -I F2=J -+J - 6.3 F12 1 F2 O y - X-direction Ultimate failure stress Oi l , - Longitudinal ultimate failure stress oru - Transverse ultimate failure stress xLW ~ Uhimate shear stress vLT - Major Poisson's ratio X t - Longitudinal ultimate tensile strength Xc - Longitudinal ultimate compressive strength Yt - Transverse ultimate tensile strength Yc - Transverse ultimate compressive strength 163 The maximum strain and maximum stress criteria assume that failure occurs whenever any one component of stress or strain attains a limiting value, independent of the other stress component values. The mode of failure changes as different maximum values are exceeded as the ply angle changes. The major difference between the maximum stress and maximum strain criteria is the presence of a Poisson term in the denominator of the .maximum strain criterion; however, the numerators are equivalent. Both the maximum stress and maximum strain criteria lack coupling or interaction effects between the various stress components. The quadratic criterion (which has gone through many revisions as the Tsai-Hill, Tsai-Wu, and Interaction criteria) takes into account the interaction between the stresses to predict failure. Literature tends to suggest that these criteria have a better correlation with experimental data. The quadratic failure theory uses a second order equation which makes no distinction between the positive and negative laminate strengths, which are usually different in magnitude; and does not distinguish between failure mode types. All of these criteria predict first ply failure, and do not consider interlaminar stresses.. Figure 6.12 shows the predicted tensile strengths for a [ ±6°]3 laminate. These results show the extreme sensitivity of strength to any misalignment of fibers when the plies are oriented close to 0°. The strength correlation for balanced angle laminates less than +30° is poor (apparently due to delamination failures described later), while for ply angles greater than ±35°, the predicted strengths are in good agreement with experimental results. All three failure theories are in close agreement with each other, especially for angles greater than ±40°. The compression strength predictions are shown in Figure 6.13. The failure mode predictions from the maximum strain and maximum stress failure criteria are shown in Table 6.5. Reference 61 determined that fiber failure only occurred 164 nro 800 Max. stress w 500 w 400 Quadratic Max. strain Database va5 100 Balanced ply angle, degrees Figure 6.12. Ultimate tensile strength versus balanced ply angle with laminate theory predicted values for first ply failure from the maximum stress, maximum strain and quadratic failure theories. ” 700 - Knn I I Max. stres r I iO v ,h'tX / S_d UUU O)C I CL E 1.0 0OnQ a E CU 0.6 0.4 1 0 2 < 0.0 1EO 1E1 1E2 1E3 1E4 1E5 1E6 1E7 Cycles to failure ■ ±30° T ±40° • ±45° A ±50° □ ±60° a 90° 1E8 Figure 6.23. Calculated compressive fatigue strain versus cycles to failure data for balanced ±30° to 90°laminates (±[0]3 laminate with D155 fabric, Vf = 0.39). 173 ^ 3.0 i & 2 5 CO K / \ / ' V\ / TX X — F 0 50 100 Z = O mm — Z = 3 mm 150 200 250 Beam X -Axis, mm 300 350 Z = 10 mm * Z = 18 mm -® - Z = 25 mm Figure 7.22. Shear stress XY at the adhesive interface of flanges (17.8 kN load). 210 Tension Flange 150 2 0 0 Beam X - Axis, mm Z = Omm - v - Z = 3 mm Z = 10 mm Z = 18 mm - a - Z = 25 mm Compression Flange __ 150 200 Beam X - Axis, mm * - Z = 10 mm —Z = O mm Z = 3 mm Z = 18 mm - B - Z = 25 mm F igu re 7 .23. Shear stress XZ at the adhesive in terface o f flanges (17.8 kN load). 211 Tension Flange 150 200 Beam X - Axis, mm Z = O mm Z = 3 mm Z = 10 mm Z = 18 mm -Es- Z = 25 mm Compression Flange __ 150 200 Beam X - Axis, mm Z = Omm Z = 3 mm Z = IO mm Z = 18 mm Z = 25 mm F igu re 7 .24 . Shear stress YZ at the adhesive in terface o f flanges (17.8 kN load). 212 delamination initiation locations .<2 1.2 E 0.4 Tension Flange Position, mm Figure 7.25. Normalized Von Mises stress on the centerline of the beam in the adhesive layer (z = 0) Outline of C-channel and matrix cracks Matrix cracks Adhesive • C-channel web Adhesive/^ Web Figure 7.26. Matrix cracking at tensile flange in Beam 28 (x = 178 mm) at delamination initiation location. 213 reported in the first section. Material coupon stiffness changes tend to be in the range of 10 to 15 percent until just prior to failure [2]. Changes greater than this are typically the result of structural breakdown as by delamination in the load-transfer area. Strains during fatigue were monitored by special clip gages described in Chapter 2, because bonded strain gages fail with the onset of matrix cracking. Studies Of Structural Details Wind turbine blades are comprised of large areas of structure to which the foregoing sections apply. However, they also contain unintentional flaws and necessary structural details such as ply drops and adhesive bonds. The beam test specimen provides a good context in which to consider certain structural details. This section includes results for the effects of severe flaws in the form of through-thickness, 13-mm diameter holes. The coupon data are presented followed by results where the detail is incorporated into beam flanges. Tests with ply drops are described in Reference 13. Effects of Through-Thickness Holes Turbine blades are subject to damage and manufacturing flaws, and in some cases may contain bolted connections. Composite materials are relatively insensitive to notches and flaws, but still demonstrate some degree of notch sensitivity in most cases [82, 83]. The most notch-sensitive composites tend to be woven biaxial fabric constructions, with finer weaves giving more notch sensitivity; in the most notch-sensitive cases, or with very large flaws, linear fracture mechanics may be applied for through-thickness flaws [82]. More commonly, stable damage development near flaws is significant, and two parameter models such as the Nuismer-Whitney model are used [83]. Sometimes, a through 214 S 0.80 Initial Stiffness (Ko)l kN/m Cycles to Failure, N Beam re 0.75 389,175 94,391 23,000 104,4075 0.60 2,030,240 783,153 3,200,000 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 Fractional Fatigue Lifetime, n/N Figure 7.27. Beam stiffness versus lifetime (n: cycles endured; N: cycles to failure). thickness hole is used in laminate tests, which tends to produce a more severe strength loss than flaws that escape visual inspection. For the carbon-fiber composites that have been investigated, impact damage and resulting delamination tend to be slightly more severe than through-holes in compression. Coupon Results With Holes We investigated flaw sensitivity for AA triax material, which, like woven fabrics [84], was expected to exhibit more notch sensitivity than separate ply laminates. Figure 7.28 gives coupon fatigue maximum stress versus cycles to failure (S-N) data for notched and unnotched specimens, where the notch was a central 13-mm diameter through-hole in a 51-mm-wide coupon. The stress plotted in Figure 7.28 is that in the far-field, away from 215 the notch. Figure 7.29 gives the same data plotted for the net cross-sectional area remaining at the hole, which is about 38-mm wide for the 51-mm overall width notched specimens. The data show moderate notch sensitivity for the static tests. The fatigue trends appear identical when the data are plotted in Figure 7.30 on a normalized basis; the unnotched and notched results are superimposed. These results are typical for those of many fiberglass laminates [I, 2], In compression, the results are slightly more notch sensitive (see Figure 7.31), but less notch sensitive in reverse loading (see Figure 7.32). However, the reverse-loading case is the most fatigue sensitive for the stresses that produce failure in a given number of cycles. Figures 7.33 and 7.34 show the progression of damage and the damage in failed coupons for the tensile fatigue cases. Figure 7.35 shows local delamination damage for a compression coupon with no hole. 2 400 Cycles to Failure ■ Unnotched ▼ Notched Figure 7.28. Tensile fatigue data for material AA coupons with and without a 13 mm diameter hole, R = 0.1. 216 Cycles to Failure ■ Unnotched ▼ Notched Figure 7.29. Tensile fatigue data for material AA coupons with and without a 13 mm diameter hole, R = 0.1. 3 0.6 Cycles to Failure ■ Unnotched ▼ Notched Figure 7.30. Normalized tensile fatigue data for material AA coupons with and without a 13 mm diameter hole, R = 0.1 (stress is divided by the one- cycle strength). 217 ro 400 350 ■ r z 200 5 100 Cycles to Failure ■ Unnotched ▼ Notched Figure 7.31. Compressive fatigue data for material AA coupons with and without a 13 mm diameter hole, R=10. CU 4 0 0 CL Q s n m •3 0 U <8 . b < t n n - 2 2 5 0< z o u O Q O E c 1 5 0 WV ■ 1 1 0 0 ^ W ■ i 50 I ▼ ▼ ■ ■I < 0 ---- - M I Mill I I I I IlH I I I t u n I I I Hi l l ...... t I H i m i...H m u I I I Mill I I I Mill 1E0 IE l I E2 1E3 1E4 1E5 1E6 1E7 I ES Cycles to Failure ■ Unnotched ▼ Notched Figure 7.32. Fatigue data for material AA coupons with and without a 13 mm diameter hole, R = -L 218 Coupon 164AA 103 MPa, R = 0.1 N = 154,275 cycles n/N = 0.52 O ° n/N = 0.77 n/N = I Figure 7.33. Damage around the 13 mm diameter hole versus fatigue lifetime. 182AA 213AA 165AA 189AA 2 1OAA 352 MPa 241 MPa 172 MPa 138 MPa 103 MPa 208AA 86 MPa Figure 7.34. Photograph of damage around the 13 mm diameter hole at different stress levels, R = 0.1 (lines indicate damage border). 219 rW am in a t i n n 25 mm gage length }- 3 « - 5 mm Delamination 1 mm Figure 7.35. Delamination on a compression fatigue coupon (coupon 127AA). Beam Results With Holes Three beams with several 13-mm-diameter holes drilled through both tension and compressive flanges (see Table 7.1) were constructed. As expected, Figure 7.36 shows that the holes did reduce the static strength and fatigue life, relative to beams without holes. Figure 7.37 confirms that the beams behave similarly to the coupons containing holes. The static-tested beam (17) and the low-cycle fatigue beam (15) failed in compression, as expected from the coupon data, although at lower stress and higher cycles, the failure shifted to the tensile flange (beam 16). Again this is consistent with the coupon predictions. The mode shift is expected by comparing Figure 7.29 with 7.31. Figure 7.38 shows the details of failed beams with holes and other details as given in Appendix B. The results of tests in this section for strength, fatigue lifetime and failure mode again show consistent behavior between coupons and beam structures. Severe flaws in the 22 0 form of 13-mm-diameter holes produce a moderate-strength reduction in the fatigue life of unflawed coupons. However, the far-field strain to produce failure at IO6 cycles is still in the 0.4% range, only slightly below that for the unnotched specimens. The unnotched and notched trend lines tend to converge at high cycles in tension, as reported in the literature [13]. Beams Utilizing a Balsa Wood Core Two beams (58 and 59) were constructed using material DD27 for the flanges and CH12 for the web. Material DD27 is the same as material DD5P with an additional center layer of 6 mm thick balsa wood to increase the moment of inertia of the flange. Both of these beams are detailed in Appendix B. The performance of these flanges was Cycles to Failure □ Beam Tension Flange v Beam Compression Flange ■ Beam Tension Flange With Hole T Beam Compression Flange With Hole Figure 7.36. Comparison of AA material flange beams without holes to AA beams with 13 mm diameter holes in the flanges. 221 Z 2.5 W ro I 2.0 «5 z I .-1.5 0.0 3] 3 ] V \ I T r D O Igp W --- 1 I I Illll — I i mm — I I i mu ---Hl-FHBl — i i11 mi ---HFFFHH---F l Mini ---F-f-1 Hill 1EO 1E3 1E4 1 ES 1 ES Cycles to Failure □ AA Tension Coupons with HoIe(R=O I) v AA Compression Coupons with HoIe(R=IO) ■ Beam Tension Flange ▼ Beam Compression Flange Figure 7.37. Comparison of AA material flange beams with holes to AA material coupons with 13 mm diameter holes. Beam 15 Compression flange Beam I 5 side view Figure 7.38. Beam 15 with holes, static compression flange failure. 222 disappointing as the fatigue lifetimes fell well short of the beams previously tested. A possible reason for this performance was the termination of the balsa wood core under the load pads. The termination could have initiated cracks which caused the delamination failures. Further research is required to develop a testing geometry which will prevent this delamination and prevent localized crushing under the load pads. Conclusions for I-beam Study The main objective was to develop a beam test specimen representative of wind turbine blade primary substructure to test the validity of using the materials database and current design methodologies for predicting structural strength, stiffness, failure mode, and fatigue lifetime. This objective was met, as the findings show that strength, stiffness, failure mode, and fatigue life can be predicted with acceptable accuracy as long as premature failure does not occur in the load introduction areas. (The specialized load introduction details for the beams are not representative of blades, but the general problem of load transfer at the hub and other special details of blades is of similar concern.) Tests using the triax (material A A) flanges and ±45° (CHlO) web showed good agreement between experimental and predicted results for strength, failure mode, and fatigue lifetime. As predicted, the failure mode shifted from compression at low cycles (only the static, one cycle tests could be conducted experimentally because of the very low cycles) to tensile flange failure at moderate to high cycles and lower loads. The poor tensile fatigue performance of triax fabric in coupons was equally evident in the beam 223 structures, with good quantitative correlation on lifetimes. The use of materials with improved fatigue resistance (material DD5P in the flanges) did raise the strain capacity of the beam in fatigue by about a factor of two, as predicted. Failures then shifted to the web flange area, which experienced severe damage, sometimes leading to delamination from the main flange. This failure mode occurred at slightly higher strains than the web material coupons could withstand (materials CHlO and CH3), because the web flange ±45° layers can deteriorate heavily before the beam fails, as compared with failure of the 0° layers in the flange, which produces rapid failure. Further increases in the 0 ° content of the web (materials CH12 and DD5P) resulted in premature load pad and shear stiffener failures. Although the failure modes were more complex with the material DD5P flanges, making validation of lifetime predictions more difficult, the beam results did fall in the strain and lifetime range predicted by the coupon database. The final sections of the chapter include results of an ongoing study that uses the beam specimen to explore the effects of flaws and structural details. A 13 mm diameter through-thickness drilled hole has been considered in the composites industry as a very severe type of flaw, worse than most flaws found in service. Coupons with holes showed moderate notch sensitivity in static tests, and similar normalized fatigue trends to unnotched coupons. Beams with holes in both flanges showed results for strength and lifetime that were consistent with the coupon data, again validating the use of coupon data for predicting structural performance. 224 CHAPTER 8 CYLINDRICAL TUBES Hollow cylindrical tapered tube geometries were developed for their use in wind turbine blade test sections on a Bergey 10 kW wind turbine (Figure LI) at the Rice Ridge Renewable Energy Park near Norris, Montana. The tubes would allow for accelerated fatigue testing of candidate fiberglass materials under actual wind loading conditions. This small, hollow cross-section geometry was selected for its simplicity and because it would develop significant stresses under the loading conditions of a small, 10 kW turbine, while maintaining a wall thickness which was sufficient for commercial reinforcing fabrics. The hollow shape is marginally representative of the hollow cross- section of larger wind turbine blades (like the AOC 15/50,50 kW machine) and fairly easy to model and manufacture. The geometry of the tube is shown in Figure 8.1 and construction is detailed in Chapter 2. A tapered tube with a varying moment of inertia allowed for a gage section where the maximum bending strains would occur, away from the stress concentrations at the ends. All the measured strains on the tube sections were obtained from this gage section unless otherwise noted. These tubes were tested in both 4-point and cantilever bending geometries. 225 25 mm H— ► Tube thickness = 3.1 mm + 38 + 305 mm ---------------------------------------------------► ~ 1 44 mm _1 External tube dimensions Figure 8.1. Hollow cylindrical tapered tube geometry. Static 4-Point Bending Tests The first stage of testing involved static 4-point bending of the tubes in the standard beam testing apparatus, described earlier. The purposes of these preliminary tests was development of the load introduction end fixtures, composite lay-up schedule, and the manufacturing process. The static 4-point bending tests dealing with tubes Tl 10 through Tl 19 are summarized in Table 8.1. Using a relatively thin, hollow cross-section in bending, the resistance to buckling is the limiting static design factor; initiation of failure in these tubes was buckling and delamination of the compression side of the gage section. Different laminate lay-up schedules were performed in an attempt to obtain gage section strength failures prior to buckling. The tubes should produce strains to failure close to those obtained in flat coupons, as did the I-beam tests. The tubes tested in 4-point bending had a 21 cm clear span between two tapered steel mandrels that were adhesively bonded with Hysol EA9309.2NA to the inside surface of the tube. The first lay-up schedule was a [0/±45/0] lay-up (similar to material DD2) using the D 155 and DB 120 fabrics. This design gave a wall thickness of 1.9 mm which 226 corresponded to a fiber volume fraction of 0.44. Tubes Tl 10, Tl 11 and Tl 12 all had very low maximum strains compared with the strains obtained from the coupon tests, indicating that the tube was buckling. Figure 8.2 shows evidence of this buckling in the bending moment versus bending strain diagram for tube Tl 10. The surface damage to Tube Tl 10 is shown in Figure 8.3. This, and subsequent images dealing with the failure surfaces, were obtained by rolling the failed tube section across a digital flatbed scanner, following the scanner sensor movement. This process allowed the entire tube surface to be displayed in one figure. The top and bottom of the figures represent the maximum tensile stress location in the gage section; the maximum compressive stress location (where failure occurred) was in the center of the figure. The right hand side of figures dealing with the cantilever tests was the end with the fixed support, damage was localized in the gage section and it is believed that the evident fiber waviness was the cause of the low failure strains. The other internal plies compressively buckled inward and could be clearly seen by viewing inside the section. The same types of failures were seen with tubes Tl 11 and Tl 12 which are detailed in Figures 8.4 through 8.7. During testing, tube T i l l was observed to change from a circular cross-section to an elliptical one prior to catastrophic failure. This tube had better fiber alignment and also reached higher failure strains than tube Tl 10. Figure 8.4 also shows a more nearly linear behavior of the tension and compressive strain gages than tube Tl 10. Tube Tl 12 had some delamination in the outside compressive plies along with a through thickness shear crack, with no other damage on the rest of the tube. The term “shear crack” refers to the evident shear distortion of the fabric across the crack, and the angular direction of the 227 Figure 8.3 shows delamination of the outside 0° ply with some fiber waviness. The crack. The cause of the through thickness crack is undetermined; this was the only tube that failed in this manner. Table 8.1. Summary of static four - point bending tests performed on tube sections. Tube Fabric lay-up Wall thickness1, mm Maximum strain (tensile/compressive), % Maximum 4- point bending moment, N-m TllO [0/±45/0] 1.9-2.0 0.49 / -0.60 310 T il l 0.85/-1.30 382 Tl 12 0.48 / -0.50 232 Tl 13 [+45/02/-45] 1.9-2.0 0 .8 2 /- 413 Tl 142 — / -0.92 509 Tl 15 0.51 /-0.32 308 Tl 16 [±45/0/+45] 3.5-3.6 2.10 / -1.41 1,551 Tl 17 1.74/-1.22 1,634 Tl 18 1.92 / -1.98 1,850 Tl 19 2.19 / -1.89 1,930 1 -Average tube Vf = 0.43 - 0.44. 2 -Tube Tl 14 had a foam core. 38 cm steel mandrel support support30 cm 61 cm 228 compression gage E 200 tension gage .E 150 .1 0.2 0.3 0.4 Maximum absolute bending strains, % Figure 8.2. Bending moment versus bending strain for Tl 10. 229 tension gage c' 300 compression gage .E 200 Maximum absolute bending strains, % Figure 8.4. Bending moment versus bending strain for Tl 11. Figure 8.5. T i l l failed tube surface. 230 tension gage compression gage - $ 100 x 50 .1 0.2 0.3 0.4 Maximum absolute bending strains, % Figure 8.6. Bending moment versus bending strain for Tl 12 Figure 8.7. Tl 12 failed tube surface. Tubes Tl 13, Tl 14 and Tl 15 had the orientation of the lay-up reversed which placed the 0° plies in the center of the thickness ([+45/02/-45]) as detailed in Figures 8.8 through 8.13. This lay-up was used to determine whether the 45° plies could add lateral 231 support the 0° plies to increase their buckling resistance. Tubes Tl 13 and Tl 14 had only one strain gage on the gage section and tube Tl 14 had the interior of the tube foamed in with “Great Stuff®” polyurethane foam manufactured by Insta-foam Products (approximate ultimate compressive strength of 80 kPa and modulus of 0.8 MPa and a density of 30 kg/m3). The foam was used to increase the failure moment of the tube by increasing the buckling resistance, and resulted in a moment capacity increase of approximately 50 percent over the other tubes. Tubes Tl 13 and Tl 15 showed little damage on the surface while tube Tl 14 (with the foam) had massive circumferential delaminations. Figure 8.10 shows the applied bending moment versus the compressive strain for tube Tl 14; the behavior was linear up to 0.8 percent strain when an audible crack was heard during the test. The graph continues non-linearly from this strain; it was not determined if the crack was the foam core delaminating from the interior tube surface 500 E 5 400 0 E I 300 O) C m 200 E=5 'I 100(O 0 0 0.2 0.4 0.6 0.8 1 Maximum bending strain, % Figure 8.8. Bending moment versus bending strain for Tube Tl 13 232 compression gage — E 400 E 300 co 100 .2 0.4 0.6 0.8 Maximum absolute bending strains, % Figure 8.10. Bending moment versus bending strain for Tl 14. 233 Figure 8.11. Tl 14 failed tube surface. m 250 tension gage —compression gage c 150 0.2 0.3 0.4 I Maximum absolute bending strains, % Figure 8.12. Bending moment versus bending strains for Tl 15. 234 or a delamination between the composite plies. Figure 8.13 details the applied bending moment versus the absolute bending strains for tube Tl 15. The compression gage deviated from a linear behavior early in the test and the failure surface showed little damage around the compression strain gage. The cause of this deviation or the lack of damage at this location was not determined. The third iteration of the laminate lay-up involved a [±45/04/±45] schedule that increased the wall thickness to 3.5 mm while maintaining a fiber volume fraction of 0.43. This lay-up caused an increase in the failure moments and strains in the tubes. Figures 8.14 through 8.20 show the failed tubes and their associated bending moment versus bending strain diagrams. The figures show much larger delaminations than the previous tubes (Tl 10 to Tl 15). Tube Tl 18 had four strain gages located 90° apart from each other and the recorded strains are shown in Figure 8.17. It can be seen from this figure that the bending strains are linear until the compression side of the tube starts to buckle inwards. The strains recorded by strain gages two and four, which should have been on the neutral axis plane of the bending beam, were picking up some minor tensile strains, 0.09% and 0.20% respectively at failure, probably due to the neutral axis shifting towards the compressive side of the tube as the tube changed shape. 235 Figure 8.13. Tl 15 failed tube surface. compression gage tension gage - S 1200 ° 1000 Maximum absolute bending strains, % Figure 8.14. Bending moment versus bending strains for Tl 16. 236 Figure 8.15. Tl 16 failed tube surface. 1500 compression gage tension gage c 1000 Maximum absolute bending strains, % Figure 8.16. Bending moment versus bending strains for Tl 17. 237 2000 E Z ■£ 1500VF = 0.36, Ave. thickness = 3.30 mm, S.D. = 0.05 mm, CoRezyn 63-AX-051 Polyester 3043 D072A118 -608 * 13 — — I 25 3044 D072A123 -562 * 13 — —— ———— I 25 3045 D072A122 -508 * 13 -------— ——— I 25 3046 D072A120 -345 10 5 ———— ———— 87,741 25 3047 D072A119 -414 10 3 — ———— 9,757 25 3048 D072A117 -414 10 4 -------— — — 2,192 25 3049 D072A116 -345 10 5 — ———— 79,404 25 3050 D072A121 -414 10 4 — ———— 6,097 25 3051 D072A115 -345 10 5 — — 136,908 25 3055 D072A110 812 * 13 28.3 2.87 I 25 3056 D072A109 789 * 13 29.3 2.70 I 25 3057 D072A108 796 * 13 27.8 2.90 I 25 3058 D072A107 483 0 .1 4 26.8 1.83 9,586 25 3059 D072A106 483 0 . 1 4 26.7 1.91 8,838 25 382 TEST & SAMPLE ID # MAX. STRESS MPa R Q Hz E GPa e % CYCLES TO FAIL WIDTH (mm) and Notes 3060 D072A105 310 0.1 10 28.2 0.96 929,460 25 3061 D072A101 483 0.1 4 31.7 1.63 5,993 25 3062 D072A102 345 0.1 5 27.7 1.14 195,791 25 3063 D072A1II 414 0.1 5 31.3 1.32 28,168 25 3064 D072A112 414 0.1 5 26.9 1.47 34,247 25 3065 D072A121 414 0.1 5 28.4 1.40 23,522 25 3066 D072A118 345 0.1 10 26.3 1.30 162,352 25 3067 D072A123 345 0.1 10 27.7 1.29 237,010 25 MATERIAL D092 Lay-up = [0]10>VF = 0.46, Ave. thickness = 3.10 mm, S.D. = 0.07 mm, CoRezyn 63-AX-051 Polyester Tests 1992 - 2013 in this section were done for Table lO.Compression tests involved a 13 mm gage length. 1992 D09201 929 * 0.25 35.1 2.82 I ZERO 1993 D09202 926 * 0.25 36.8 2.87 I ZERO 1994 D09203 911 * 0.25 34.3 3.14 I ZERO 1995 D09204 134 * 0.25 12.2 —— — I ±45 1996 D09205 37 * 0.25 10.1 0.35 I 90 1997 D09208 -761 * 0.25 28.4 -2.6 I ZERO 1998 D09209 -745 * 0.25 30.6 -2.4 I ZERO 1999 D09210 -783 * 0.25 31.8 -2.5 I ZERO 2000 D09211 -130 * 0.25 12.3 ———— I ±45 2001 D09212 -129 * 0.25 10.9 ———— I ±45 2002 D09213 -130 * 0.25 11.1 ———— I ±45 2003 D09214 -141 * 0.25 7.38 -1.91 I 90 2004 D09215 40 * 0.25 7.10 0.56 I 90 2005 D09216 -130 * 0.25 7.65 -1.91 I 90 2006 D09217 150 * 0.25 9.44 —— — I ±45 2007 D09250 -816 * 0.25 32.5 -1.63 I ZERO 2008 D09251 -758 * 0.25 31.4 -1.47 I ZERO 2009 D09252 -127 * 0.25 6.62 -1.92 I 90 2010 D09253 -129 * 0.25 14.2 — — I ±45 2011 D09254 1041 * 0.25 34.9 3.09 I ZERO 2012 D09255 140 * 0.25 12.5 ———— I ±45 2013 D09256 38 * 0.25 9.79 0.37 I 90 MATERIAL D092B Lay-up = [OJ9iVf = 0.41, Ave. thickness =2.76 mm, S.D. = 0.12 mm, CoRezyn 63-AX-051 Polyester 2144 D092B105 994 * 13 35.6 2.80 I 25 tab 2145 D092B104 907 * 13 32.9 2.86 I 25 tab 2146 D092B106 959 * 13 34.7 2.80 I 25 tab 2147 D092B107 552 0.1 4 36.1 1.60 8,610 25 tab 2148 D092B109 552 0.1 4 32.9 1.70 12,301 25 tab 2149 D092B110 414 0.1 15 36.8 1.13 302,338 25 2150 D092B103 414 0.1 15 32.6 1.21 259,952 25 2151 D092B111 414 0.1 15 31.9 1.30 236,479 25 2152 D092B108 345 0.1 15 33.9 1.04 1,557,555 25 383 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes 2153 D092B101 345 0.1 15 32.0 1.09 957,554 25 2154 D092B102 345 0.1 15 35.7 0.98 1,847,878 25 2380 D092B230 878 * 13 33.4 2.62 I 25 2381 D092B208 875 * 13 34.3 2.55 I 25 2382 D092B204 834 * 13 34.1 2.45 I 25 2383 D092B216 552 0.1 4 34.0 1.62 2,914 25 2384 D092B210 552 0.1 4 32.2 1.71 3,142 25 2385 D092B201 552 0.1 4 33.9 1.63 3,756 25 2386 D092B213 414 0.1 10 32.9 1.26 126,113 25 2387 D092B203 414 0.1 5 33.9 1.22 165,310 25 2388 D092B205 345 0.1 12 33.7 1.02 892,557 25 2389 D092B209 345 0.1 12 32.4 1.06 1,112,027 25 2390 D092B21I 414 0.1 10 33.2 1.25 171,967 25 2639 D092B301 -684 * 13 — — I 25 2640 D092B302 -710 * 13 ———— ———— I 25 2641 D092B303 -708 * 13 ———— ———— I 25 2642 D092B305 -630 * 3 — __ I 25 2643 D092B306 -610 * 3 ———— ———— I 25 2644 D092B308 MATERIAL D092D -705 * 3 I 25 Lay-up= [OI7iVf = 0.30, Ave. thickness =2.64 mm, S.D. = 0.11 mm, CoRezyn 63-AX-051 Polyester 2391 D092D105 736 * 13 25.4 2.89 I 25 2392 D092D107 722 * 13 25.6 2.81 I 25 2393 D092D111 734 * 13 25.8 2.84 I 25 2394 D092D108 482 0.1 2 24.4 1.98 3,342 25 2395 D092D110 482 0.1 4 23.6 2.04 2,650 25 2396 D092D103 414 0.1 8 25.4 1.63 113,301 25 2397 D092D109 345 0.1 10 25.6 1.35 813,359 25 2398 D092D104 414 0.1 8 27.4 1.51 75,856 25 2399 D092D102 345 0.1 12 24.3 1.42 291,147 25 2400 D092D106 345 0.1 15 26.1 1.30 948,810 25 2645 D092D301 -574 * 3 ———— ———— I 25 2646 D092D302 -515 * 3 ———— ——— I 25 2647 D092D303 -532 * 3 ——— ———— I 25 2648 D092D304 -538 * 3 — —— ———— I 25 MATERIAL D092F Lay-up = [OI12iVf = 0.50, Ave. thickness = 3.00 mm, S.D. = 0.04 mm, CoRezyn 63-AX-051 Polyester 2178 D092F110 1090 * 13 35.9 3.04 I 25 2179 D092F112 1105 * 13 40.5 2.85 I 25 tab 2180 D092F103 1141 * 13 41.8 2.85 I 25 2181 D092F1II 1203 * 13 42.2 2.86 I 25 tab 2182 D092F107 414 0.1 15 44.1 0.97 221,920 25 2183 D092F109 414 0.1 15 39.9 1.03 92,864 25 2184 D092F105 414 0.1 15 37.2 1.12 138,489 25 384 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes 2185 D092F106 345 0.1 15 42.6 0.81 864,540 25 2186 D092F101 345 0.1 15 38.3 0.90 387,503 25 2187 D092F102 552 0.1 4 41.8 1.32 15,665 25 tab 2188 D092F124 552 0.1 4 44.6 1.24 31,284 25 tab 2653 D092F123 -615 * 3 —— — I 25 2654 D092F126 -692 * 3 —— ——— I 25 2655 D092F122 -697 * 3 —— - — —— I 25 2656 D092F121 MATERIAL D092G -712 * 3 I 25 Lay-up= [0]13 ,Vf = 0.58, Ave. thickness =3.25 mm, S.D. =0.05 mm, CoRezyn 63-AX-051 Polyester 2155 D092G113 1,130 * 13 42.2 2.70 I 25 tab 2156 D092G105 1,206 * 13 43.3 2.80 I 25 tab 2157 D092G103 1,182 * 13 41.8 2.80 I 25 tab 2158 D092G109 690 0.1 2 43.2 1.62 484 25 tab 2159 D092G112 414 0.1 4 44.1 0.94 12,691 25 tab 2160 D092G106 414 0.1 4 45.0 0.90 15,436 25 tab 2161 D092G101 552 0.1 I 46.0 1.31 2,113 25 tab 2162 D092G104 552 0.1 2 45.4 1.22 2,942 25 tab 2163 D092G102 414 0.1 2 43.4 0.97 11,735 25 tab 2164 D092G110 552 0.1 2 47.2 1.20 2,700 25 tab 2165 D092G108 276 0.1 10 6.79 0.62 261,247 25 tab 2166 D092G111 207 0.1 10 44.0 0.47 3,000,000 25 R tab 2167 D092G114 276 0.1 10 47.7 0.58 159,725 25 tab 2168 D092G107 276 0.1 10 50.0 0.55 95,939 25 tab 2169 D092G205 276 0.1 15 50.7 0.55 472,372 25 tab 2170 D092G207 276 0.1 10 51.1 0.56 494,104 25 tab 2171 D092G206 276 0.1 10 50.7 0.53 368,039 25 tab 2173 D092G201 414 0.1 10 46.8 0.90 36,932 25 tab 2174 D092G202 414 0.1 4 49.2 0.90 29,096 25 tab 2175 D092G-204 276 0.1 10 49.1 0.56 700,000 25 R tab 2177 D092G105 345 0.1 12 46.1 0.81 478,382 25 tab 2354 D092G205 1196 * 13 44.5 2.89 I 25 tab 2355 D092G209 1133 * 13 43.4 2.61 I 25 tab 2356 D092G201 1161 * 13 45.0 2.60 I 25 tab 2357 D092G212 276 0.1 12 47.8 0.58 874,379 25 tab 2358 D092G207 552 0.1 5 47.5 1.16 12,811 25 tab 2359 D092G202 552 0.1 5 41.5 1.33 9,807 25 tab 2360 D092G211 552 0.1 5 45.2 1.22 9,091 25 tab 2361 D092G216 690 0.1 2 42.1 1.64 1,360 25 tab 2362 D092G215 690 0.1 2 45.9 1.50 2,083 25 tab 2363 D092G214 414 0.1 10 41.9 0.99 113,852 25 tab 2364 D092G210 414 0.1 10 43.0 0.96 92,451 25 tab 2365 D092G213 276 0.1 15 45.6 0.60 6,654,291 25 tab 2366 D092G203 414 0.1 10 44.5 0.93 135,121 25 tab 2649 D092G301 -658 * 3 -- — — I 25 2650 D092G302 -645 * 3 --- — —— I 25 2651 D092G303 -629 * 3 ———— ——— I 25 385 TEST & SAMPLE ID # MAX. STRESS MPa R Q Hz E GPa e % CYCLES TO FAIL WIDTH (mm) and Notes 2652 D092G304 -837 * 3 —— —— I 25 2786 D092G130 -621 10 4 ———— ———— 13,859 25 2787 D092G120 -621 10 5 ———— ———— 7,978 25 2789 D092G126 -621 10 5 ———— ———— 6,124 25 2790 D092G131 -552 10 12 —— — ———— 19,386 25 2791 D092G123 -552 10 12 ———— — — 27,412 25 2792 D092G124 -552 10 12 ———— ———— 11,391 25 2793 D092G132 -414 10 12 ——— — —- 1,864,286 25 2794 D092G128 -483 10 10 —— — — —— 481,468 25 2795 D092G121 -483 10 10 — 298,071 25 2796 D092G127 -483 10 10 — — 331,041 25 MATERIAL D155 Lay-up = [0]6,VF = 0.45, Ave. thickness = 2.74 mm, S.D. = 0.10 mm, CoRezyn 63-AX-051 Polyester Tests 2014 - 2035 in this section were done for Table lO.Compression tests involved a 13 mm gage length. 2014 D15501 984 * 0.25 39.0 2.90 I ZERO 2015 DI5502 898 * 0.25 36.3 2.69 I ZERO 2016 DI5503 976 * 0.25 38.9 2.87 I ZERO 2017 DI5504 93 * 0.25 12.8 — — I ±45 2018 DI5505 25 * 0.25 9.12 0.43 I 90 2019 DI5506 30 * 0.25 9.24 0.37 I 90 2022 D15509 -109 * 0.25 14.0 -3.2 I ±45 2023 D15510 -106 * 0.25 15.1 -3.72 I ±45 2024 D15511 -122 * 0.25 8.31 -1.62 I 90 2025 D15512 -118 * 0.25 7.65 -1.43 I 90 2026 D15513 -727 * 0.25 32.1 -2.48 I ZERO 2027 D15514 -710 * 0.25 31.8 -1.77 I ZERO 2028 D15515 -756 * 0.25 29.6 -1.34 I ZERO 2029 D15516 104 * 0.25 12.3 ———— I ±45 2030 D15517 103 * 0.25 10.8 —— — I ±45 2031 DI5550 -730 * 0.25 32.3 -2.18 I ZERO 2032 D15551 -807 * 0.25 33.0 -2.14 I ZERO 2033 D15552 -147 * 0.25 7.72 -1.96 I 90 2034 D15553 1088 * 0.25 39.0 2.85 I ZERO 2035 D15554 86 * 0.25 13.2 ———— I ±45 MATERIAL D155B Lay-up = [0]5 ,Vf = 0.39, Ave. thickness = 2.70 mm, S.D. = 0.11 mm, CoRezyn 63-AX-051 Polyester 2110 D155B65 935 * 13 34.8 2.80 I 25 tab 2111 D155B71 961 * 13 29.6 3.25 I 25 tab 2112 D155B61 911 * 13 33.8 2.80 I 25 2113 D155B60 552 0.1 2 31.9 1.86 1,831 25 2114 D155B72 552 0.1 2 29.8 1.92 3,911 25 2115 D155B63 414 0.1 5 31.9 1.44 85,156 25 2116 D155B70 414 0.1 10 28.6 1.49 108,103 25 2117 D155B69 276 0.1 20 28.5 1.08 8,000,000 25 386 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes 2118 D155B68 552 0.1 4 30.9 1.83 6,582 25 tab 2119 D155B66 690 0.1 I 32.2 2.32 139 25 2120 D155B62 345 0.1 10 33.0 1.10 1,230,231 25 tab 2121 D155B64 414 0.1 10 33.0 1.28 75,774 25 tab 2122 D155B67 345 0.1 12 29.5 1.19 721,864 25 tab 2123 D155B81 345 0.1 10 32.5 1.15 572,173 25 2203 D155B200 755 * 13 31.1 2.43 I 25 2204 D155B209 779 * 13 28.2 2.76 I 25 2205 D155B215 785 * 13 28.5 2.75 I 25 2206 D155B201 483 0.1 4 32.6 1.48 6,979 25 2207 D155B207 483 0.1 4 33.1 1.46 16,497 25 2208 D155B205 414 0.1 7 32.2 1.28 82,605 25 2209 D155B203 414 0.1 8 36.8 1.13 68,483 25 2236 D155B212 345 0.1 15 33.6 1.02 967,901 25 2237 D155B210 345 0.1 15 30.1 1.15 1,104,634 25 2338 D155B202 483 0.1 5 30.4 1.59 19,814 25 2339 D155B213 552 0.1 3 32.2 1.71 2,141 25 2340 D155B208 552 0.1 4 30.3 1.82 2,305 25 2341 D155B211 552 0.1 4 31.8 1.73 1,733 25 2342 D155B214 414 0.1 10 30.8 1.34 48,181 25 2657 D155B301 -620 # 3 ——— ———— I 25 2658 D155B302 -666 * 3 ———— ———— I 25 2659 D155B303 -642 * 3 ———— —— I 25 2660 D155B304 -656 # 3 ———— — — I 25 2776 D155B174 -681 * 3 ———— —— I 25 2777 D155B177 -517 10 I ———— ——— 178 25 2778 D155B175 -414 10 10 ———— ——— 76,348 25 2779 D155B178 -414 10 10 ———— ———— 61,956 25 2780 D155B180 -345 10 12 -------— ———— 954,990 25 2781 D155B176 -345 10 12 — ———— 893,962 25 2782 D155B173 -345 10 12 — —------- 1,121,768 25 2783 D155B181 -414 10 10 ———— ———— 172,874 25 2784 D155B179 -483 10 2 —— — — 886 25 3735 D155B222 831 * 13 32.8 ———— I 25 3736 D155B223 845 * 13 ———— ———— I 25 3737 D155B218 775 * 13 — — ———— I 25 3738 D155B218 MATERIAL Dl 55C 843 * 13 I 25 Lay-up= [0]7 ,Vf = 0.51, Ave. thickness =2.99 mm, S.D. = 0.09 mm, CoRezyn 63-AX-051 Polyester 2124 D155C111 1189 * 13 33.6 3.57 I 25 2125 D155C109 1184 * 13 32.3 3.66 I 25 2126 D155C107 1188 * 13 34.6 3.43 I 25 2127 D155C101 827 0.1 2 32.5 2.55 315 25 2128 D155C105 552 0.1 5 34.0 1.59 11,103 25 2129 D155C110 552 0.1 5 33.4 1.62 10,021 25 2130 D155C106 414 0.1 12 33.7 1.24 189,546 25 2131 D155C104 345 0.1 15 35.6 1.01 1,276,914 25 387 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS Hz GPa % TO FAIL (mm) ID # 2132 D155C108 MPa 414 0.1 10 37.0 1.23 133,885 and Notes 25 2133 D155C100 414 0.1 10 34.3 1.24 206,447 25 2134 D155C114 552 0.1 4 32.1 1.68 14,762 25 2135 D155C102 345 0.1 12 35.1 0.99 854,271 25 2136 D155C103 345 0.1 12 32.2 1.04 644,464 25 2220 D155C202 1129 * 13 43.0 2.62 I 25 2221 D155C205 1208 * 13 42.6 2.83 I 25 2222 D155C203 1152 * 13 43.8 2.63 I 25 2223 D155C206 552 0.1 5 46.7 1.18 19,546 25 2224 D155C207 552 0.1 5 43.0 1.28 19,611 25 2225 D155C209 552 0.1 5 46.7 1.09 25,014 25 2227 D155C210 345 0.1 10 41.4 0.83 1,369,554 25 2228 D155C213 345 0.1 12 43.4 0.75 1,251,972 25 2229 D155C211 690 0.1 2 42.5 1.65 3,370 25 2230 D155C208 690 0.1 2 42.8 1.61 2,480 25 2231 D155C201 414 0.1 5 45.0 0.92 196,825 25 2232 D155C212 414 0.1 10 43.4 0.95 278,697 25 2233 D155C204 414 0.1 10 41.8 0.99 188,541 25 2234 D155C216 690 0.1 2 40.5 1.70 3,610 25 2235 D155C217 345 0.1 15 42.4 0.81 1,182,710 25 2661 D155C301 -847 * 3 —— — —— — I 25 2662 D155C302 -734 * 3 ———— — —— I 25 2663 D155C303 -752 * 3 ———— ———— I 25 2664 D155C304 -841 * 3 — — I 25 MATERIAL D155G Lay-up = [0]8 ,Vf = 0.59, Ave. thickness =2.81 mm, S.D. = 0.08 mm, CoRezyn 63-AX-051 Polyester 2189 D155G104 1318 * 13 48.4 2.72 I 25 tab 2190 D155G110 1320 * 13 48.2 2.74 I 25 tab 2191 D155G115 1303 * 13 46.7 2.80 I 25 tab 2192 D155G103 690 0.1 4 49.8 1.39 4,546 25 tab 2193 D155G107 690 0.1 2 46.3 1.49 1,839 25 tab 2194 D155G106 552 0.1 5 49.0 1.13 14,842 25 tab 2195 D155G109 552 0.1 5 51.3 1.08 10,796 25 tab 2196 D155G108 345 0.1 12 52.6 0.66 137,665 25 tab 2197 D155G105 345 0.1 12 46.2 0.75 164,363 25 tab 2198 D155G114 276 0.1 12 44.2 0.62 1,154,036 25 tab 2199 D155G102 276 0.1 12 41.4 0.66 817,204 25 tab 2200 D155G101 345 0.1 10 44.5 0.78 169,202 25 tab 2201 D155G112 690 0.1 2 45.2 1.53 2,546 25 tab 2202 D155G113 552 0.1 5 43.7 1.26 11,201 25 tab 2665 D155G301 -729 * 13 ———— — — I 25 2666 D155G302 -647 * 13 — —— — I 25 2667 D155G303 -698 * 13 — — — — I 25 2668 D155G354 -783 * 13 ———— — I 25 2766 D155G305 -552 10 12 — — 38,446 25 2767 D155G306 -552 10 12 — — 130,068 25 2768 D155G309 -552 10 12 — — 57,998 25 388 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # 2770 D155G307 STRESS MPa -483 10 Hz GPa 12 — % TO FAIL 161,615 (mm) and Notes 25 2771 D155G305 -483 10 12 — —— 74,321 25 2772 D155G304 -730 * 13 —— I 25 2773 D155G316 -621 10 I — —— 90 25 2774 D155G320 -621 10 I — —— 136 25 2775 D155G310 -621 10 I — —— 62 25 3117 D155G315 -821 * 13 — —— I 25 3118 D155G302 -752 * 13 — —— I 25 3119 D155G310 -722 * 13 — —— I 25 Tests 3599 - 3613 involved a gage length of 13 mm (strain rate effect tests). 3599 D155G314 -627 * 0.025 — I 25 tab 3600 D155G321 -660 * 0.025 — —— I 25 tab 3601 D155G323 -654 * 0.025 — —— I 25 tab 3602 D155G311 -739 * 2.54 — —— I 25 tab 3603 D155G322 -723 * 2.54 — I 25 tab 3604 D155G324 -701 * 2.54 — —— I 25 tab 3605 D155G317 -673 * 12.7 — —— I 25 tab 3606 D155G313 -762 * 12.7 — —— I 25 tab 3607 D155G319 -784 * 12.7 — —— I 25 tab 3608 D155G335 -757 * 25.4 — —— I 25 tab 3609 D155G330 -776 * 25.4 — —— I 25 tab 3610 D155G333 -768 * 25.4 — —— I 25 tab 3611 D155G332 -735 * 127 — —— I 25 tab 3612 D155G331 -796 * 127 — —— I 25 tab 3613 D155G336 -755 * 127 — —— I 25 tab Tests 3614 - 3625 involved a gage length of 100 mm (strain rate effect tests). 3614 D155G217 964 * 0.025 ..............— I 25 tab 3615 D155G219 833 * 0.025 — —— I 25 tab 3616 D155G214 897 * 0.025 — —— I 25 tab 3617 D155G216 1086 * 2.54 — —— I 25 tab 3618 D155G221 1143 * 2.54 — —— I 25 tab 3619 D155G222 1061 * 2.54 — —— I 25 tab 3620 D155G223 1140 * 12.7 — — I 25 tab 3621 D155G226 1222 * 12.7 — —— I 25 tab 3622 D155G225 1024 * 12.7 — — I 25 tab 3623 D155G224 1086 * 63.5 — —— I 25 tab 3624 D155G218 1100 * 63.5 —- — I 25 tab 3625 D155G220 1136 * 63.5 — — I 25 tab MATERIAL Dl 55H Lay-up = [0]7 ,Vf = 0.49, Ave. thickness = 2.93 mm, S.D. = 0.10 mm, CoRezyn 63-AX-051 Polyester, No Stitching. Stitching in the D155 fabric was removed to study this effect. 2210 D155H106 961 * 13 34.3 2.80 I 25 2211 1)15511111 886 * 13 33.1 2.68 I 25 2212 1)15511103 903 * 13 34.7 2.61 I 25 2215 D155H108 552 0.1 5 34.4 1.60 39,227 25 2216 D155H109 552 0.1 5 35.4 1.56 22,154 25 2217 D155H122 1076 * 13 40.1 2.98 I has stitch 389 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS Hz GPa % TO FAIL (mm) ID # MPa and Notes 2218 D155H121 1178 * 13 40.7 2.89 I has stitch 2219 D155H120 1109 * 13 40.5 2.74 I has stitch 2226 D155H102 552 0.1 5 33.9 1.62 41,215 25 2344 D155H210 483 0.1 10 37.0 1.30 156,200 25 2346 D155H204 1101 * 13 41.7 2.63 I 25 2347 D155H203 483 0.1 15 38.8 1.24 128,523 25 2348 D155H208 483 0.1 12 39.7 1.21 195,322 25 2349 D155H209 414 0.1 15 40.0 1.04 3,219,571 25 2350 D155H201 414 0.1 15 40.5 1.02 1,211,477 25 2351 D155H212 690 0.1 4 42.0 1.64 2,953 25 2352 D155H206 690 0.1 4 41.4 1.67 2,264 25 2353 D155H207 690 0.1 4 40.7 1.70 1,822 25 2669 D155H301 -718 * 3 ———— ———— I 25 2670 D155H302 -686 * 3 ———— ———— I 25 2671 D155H303 -623 * 3 — —— I has stitch 2672 D155H304 -864 * 3 — ———— I has stitch 2673 D155H305 -795 * 3 ———— ———— I has stitch 2674 D155H306 -846 * 3 — — I has stitch MATERIAL D155 J Lay-up = [0]6,VF = 0.58, Ave. thickness = 3.54 mm, S.D. =0.11 mm, CoRezyn 63-AX-051 Polyester, No Stitching. Stitching in the D155 fabric was removed to study this effect. 2428 D155J111 1,098 * 13 49.8 2.65 I 25 2429 DlSSJl14 1,190 * 13 47.5 2.51 I 25 2430 D155J101 1,140 * 13 48.6 2.43 I 25 2431 D155J103 690 0.1 5 44.9 1.54 6,213 25 2432 D155J115 690 0.1 5 50.0 1.38 7,977 25 2433 D155J106 690 0.1 5 46.8 1.47 4,784 25 2434 D155J108 552 0.1 5 50.0 ———— 20,345 25 2435 D155J105 552 0.1 5 50.0 1.10 73,109 25 2436 D155J109 414 0.1 12 47.0 0.88 684,350 25 2437 D155J113 552 0.1 5 47.8 1.15 35,652 25 2438 1)1551116 414 0.1 12 47.8 0.79 912,579 25 2439 D155J107 552 0.1 5 45.2 1.22 89,980 25 2440 D155J104 414 0.1 12 47.3 0.86 485,216 25 2675 D155J301 -826 * 3 —— — ———— I 25 2676 D155J302 -704 * 3 ———— ——— I 25 2677 D155J303 -796 * 3 — ———— I 25 2678 D155J304 -777 * 3 — —— — I 25 MATERIAL Dl 55K Lay-up = [0]7 ,Vf = 0.33, Ave. thickness = 4.45 mm, S.D. = 0.10 mm, CoRezyn 63-AX-051 Polyester 3673 D155K110 872 3674 D155K111 881 3675 D155K109 830 3676 1)155X108 414 13 28.5 3.15 I 25 13 29.6 2.98 I 25 13 28.5 2.91 I 25 2 27.1 1.58 7,569 250.1 390 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS Hz GPa % TO FAIL (mm) ID # 3677 D155K112 MPa 414 0.1 4 28.7 1.54 13,447 and Notes 25 3678 D155K101 414 0.1 4 26.3 1.59 6,267 25 3679 D155K113 276 0.1 12 28.5 0.97 764,138 25 3680 D155K102 276 0.1 12 26.7 1.01 1,305,237 25 3681 D155K103 276 0.1 12 28.6 0.96 1,733,768 25 3682 D155K105 345 0.1 6 30.1 1.18 175,689 25 3683 D155K104 345 0.1 6 27.9 1.26 106,359 25 3684 D155K107 345 0.1 6 26.9 1.29 152,853 25 3685 D155K106 483 0.1 I 28.1 2.12 576 25 3686 D155K120 483 0.1 I 27.3 1.90 2,594 25 3687 D155K121T 23.8 * 13 8.00 0.30 I 25 3688 D155K122T 24.9 * 13 8.36 0.29 I 25 3689 D155K123T 18.9 * 13 8.52 0.22 I 25 3841 D155K125 -500 * 13 ———— ——— I 25 3842 D155K126 -624 * 13 ———— — —— I 25 3843 D155K127 -527 * 13 — — I 25 MATERIAL DB 120 Lay-up = [0]16 ,Vf = 0.44, Ave. thickness = 2.69 mm, S.D. = 0.10 mm, CoRezyn 63-AX-051 Polyester Tests 2055 - 2074 in this section were done for Table lO.Compression tests involved a 13 mm gage length. ±45 degree fabric was separated into +45 and -45 degree plies and rotated to 0 degrees. 2055 D B 12001 6 1 0 * 0 .2 5 26 .5 2 .65 I ZERO 2056 D B 12 0 0 2 5 9 6 * 0 .2 5 2 6 .8 2.41 I ZERO 2057 DB 12003 83 * 0 .2 5 9 .4 5 ——— I ±45 2058 DB 12 0 0 4 85 * 0 .25 9 .1 0 ———— I ±45 2059 DB 12 005 85 * 0 .2 5 9 .8 6 —— — I ±45 2 060 D B 12 0 0 6 87 * 0 .2 5 8 .89 —— — I ±45 2061 D B 12 0 0 7 26 * 0 .25 7 .2 4 0 .3 9 I 9 0 2 0 6 2 DB 12 0 0 8 -5 5 4 * 0 .25 18 .9 —— — I ZERO 2063 DB 12 0 0 9 -555 * 0 .25 19 .7 ———— I ZERO 2064 D B 1 2 0 1 0 -5 4 5 * 0 .2 5 19 .4 ———— I ZERO 2065 D B 12 0 1 1 -1 1 6 * 0 .25 8 .83 — —— I ±45 2 0 6 6 D B 1 2 0 1 2 -1 2 0 * 0 .25 9 .8 6 —— — I ±45 2067 DB 12 013 -123 * 0 .25 9 .31 — —— I ±45 2068 DB 12014 -1 2 0 * 0 .25 6 .9 6 -2 .2 0 I 90 2069 D B 12 0 1 5 -1 1 7 * 0 .25 6 .41 -1 .7 0 I 90 2 070 D B 1 2 0 1 6 -1 0 4 * 0 .25 6 .5 5 -2 .1 0 I 9 0 2071 D B 12 0 1 7 6 16 * 0 .25 2 4 .8 2 .6 0 I ZERO 2072 D B 1 2 0 1 8 24 * 0 .25 7 .7 2 0 .3 2 I 9 0 2073 D B 12 0 5 0 619 * 0 .2 5 2 8 .2 2 .3 0 I ZERO 2074 D B 12 0 5 1 104 * 0 .2 5 9 .7 2 -------— I ±45 3 9 1 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS Hz GPa % TO FAIL (mm) ID # MPa and Notes MATERIAL DB240 Lay-up = [0]8 ,Vf = 0.46, Ave. thickness = 2.77 mm, S.D. = 0.12 mm, CoRezyn 63-AX-051 Polyester Tests 2075 - 2093 in this section were done for Table 10. Compression tests involved a 13 mm gage length. ±45 degree fabric was separated into +45 and -45 degree plies and rotated to 0 degrees. 2075 DB24001 701 * 0.25 30.8 2.60 I ZERO 2076 DB24002 715 * 0.25 30.1 2.60 I ZERO 2077 DB24003 669 * 0.25 31.1 2.50 I ZERO 2078 DB24004 69 * 0.25 10.9 ———— I ±45 2079 DB24005 69 * 0.25 10.1 ——— I ±45 2080 DB24006 68 * 0.25 9.90 —— — I ±45 2081 DB24007 -551 * 0.25 25.9 -1.60 I ZERO 2082 DB24008 -507 * 0.25 24.8 -1.70 I ZERO 2083 DB24009 -557 * 0.25 25.6 -1.60 I ZERO 2084 DB24010 -122 * 0.25 11.0 ———— I ±45 2085 DB24011 -101 * 0.25 10.3 ——— I ±45 2086 DB24012 -128 * 0.25 10.3 ———— I ±45 2087 DB24013 -125 * 0.25 6.32 -1.80 I 90 2088 DB24014 -118 * 0.25 6.69 -1.65 I 90 2089 DB24015 -122 * 0.25 7.08 -1.62 I 90 2090 DB24016 20 * 0.25 7.58 0.29 I 90 2091 DB24017 19 * 0.25 7.10 0.26 I 90 2092 DB24050 703 * 0.25 32.2 2.85 I ZERO 2093 DB24051 70 * 0.25 10.1 — — I ±45 392 ANGLE PLY TESTING The angled materials in this section were constructed using the D155 fabric. MATERIAL Dl 55B Lay-up = [0]5 ,Vf = 0.39, Ave. thickness = 2.70 mm, S.D. = 0.11 mm, CoRezyn 63-AX-051 Polyester TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes 2203 D155B200 755 * 13 31.1 2.43 I 25 2204 D155B209 779 * 13 28.2 2.76 I 25 2205 D155B215 785 * 13 28.5 2.75 I 25 2206 D155B201 483 0.1 4 32.6 1.48 6,979 25 2207 D155B207 483 0.1 4 33.1 1.46 16,497 25 2208 D155B205 414 0.1 7 32.2 1.28 82,605 25 2209 D155B203 414 0.1 8 36.8 1.13 68,483 25 2236 D155B212 345 0.1 15 33.6 1.02 967,901 25 2237 D155B210 345 0.1 15 30.1 1.15 1,104,634 25 2338 D155B202 483 0.1 5 30.4 1.59 19,814 25 2339 D155B213 552 0.1 3 32.2 1.71 2,141 25 2340 D155B208 552 0.1 4 30.3 1.82 2,305 25 2341 D155B21I 552 0.1 4 31.8 1.73 1,733 25 2342 D155B214 414 0.1 10 30.8 1.34 48,181 25 MATERIAL IOD155 Lay-up = [±10]3,Vf = 0.38, Ave. thickness = 3.47 mm, S.D. =0.17 mm, CoRezyn 63-AX-051 Polyester 2513 1 0D 155 1 2 2 271 * 13 2 8 .6 0 .9 0 I 25 2 514 1 0D 155 1 2 7 303 * 13 28 .5 1 .00 I 25 2515 1 0D 15 5 1 2 0 249 * 13 25 .5 0 .9 5 I 25 2 5 6 6 1 0D 155128 172 0.1 10 27 .9 0 .6 0 167 ,5 3 8 25 2 569 1 0D 155213 172 0.1 8 26 .1 0 .6 6 178 ,2 6 6 25 2 5 7 0 IOD155 2 0 8 172 0.1 10 2 9 .2 0 .6 4 2 0 7 ,9 5 7 25 2571 IOD1552 0 5 284 * 13 2 9 .0 0 .9 8 I 25 2572 IOD155 2 0 9 207 0.1 5 2 9 .4 0 .71 18 ,193 25 2573 1 0D 155 2 1 0 207 0.1 5 32 .3 0 .6 4 2 1 ,7 8 0 25 2574 1 0D 155 2 1 2 207 0.1 5 29 .3 0 .7 2 16 ,360 25 2575 10D 155215 155 0.1 12 29 .5 0 .5 3 1 ,7 6 4 ,8 8 3 25 2583 1 0D 1 5 5 1 14 -405 * 13 — — —— — I 25 2584 1 0D 155 1 0 6 -3 4 3 * 13 —— — -------— I 25 2585 1 0D 1 5 5 1 I2 -4 0 6 * 13 ———— ———— I 25 2 5 8 6 1 0D 1 5 5 1 13 -381 * 13 ———— ———— I 25 MATERIAL 20D155 Lay-up = [±20]3,Vf = 0.39, Ave. thickness = 3.21 mm, S.D. = 0.14 mm, CoRezyn 63-AX-051 Polyester 2510 20D155101 244 * 13 24.3 1.08 I 25 2511 20D155104 269 * 13 23.2 1.20 I 25 2512 20D155107 290 * 13 25.1 1.40 I 25 2558 20D155113 172 0.1 5 26.9 0.71 21,427 25 393 TEST & SAM PLE ID # M AX . STRESS M Pa R Q Hz E GPa e % CYCLES TO FA IL W IDTH (mm ) and N otes 2 5 59 2 0 D 1 5 5 1 12 172 0.1 7 25 .3 0 .6 9 38 ,4 7 5 25 2 5 6 0 2 0D 155 1 1 1 138 0.1 12 24 .5 0 .5 8 8 3 5 ,9 8 6 25 2561 2 0D 1 5 5 1 0 8 172 0.1 7 24 .8 0 .7 6 2 5 ,4 7 5 25 2 562 2 0D 1 5 5 1 0 6 207 0.1 2 2 7 .0 0 .83 2 ,2 4 4 25 2563 2 0 D 1 5 5 1 10 207 0.1 2 23 .8 0 .9 0 860 25 2 564 2 0D 1 5 5 1 1 6 207 0.1 2 2 5 .8 0 .8 8 2 ,7 7 9 25 2565 2 0D 1 5 5 1 0 2 138 0.1 15 24 .1 0 .5 6 7 4 2 ,1 5 4 25 2587 2 0D 155301 -2 8 4 * 13 — ———— I 25 2588 2 0D 1 5 5 3 0 2 -2 8 9 * 13 ———— ——— I 25 2589 2 0D 1 5 5 3 0 3 -271 * 13 ———— ———— I 25 2 5 9 0 2 0D 1 5 5 3 0 4 -303 * 13 ——— — —— I 25 MATERIAL 30D155 Lay-up = [±30]3 ,Vf = 0.40, Ave. thickness = 3.11 mm, S.D. =0.14 mm, CoRezyn 63-AX-051 Polyester 2507 30D155107 183 * 13 17.8 1.40 I 25 2508 30D155104 184 * 13 16.1 1.60 I 25 2509 30D155113 141 * 13 18.1 1.60 I 25 2537 30D155114 103 0.1 5 18.3 0.56 15,975 25 2538 30D155110 103 0.1 8 17.2 0.63 25,545 25 2539 30D155112 69 0.1 15 19.7 0.37 2,525,000 25 R 2540 30D155111 69 0.1 25 17.0 0.37 2,000,000 25 R 2541 30D155109 86 0.1 20 16.4 0.52 84,851 25 2542 30D155108 86 0.1 20 18.8 0.42 214,208 25 2543 30D155115 86 0.1 20 17.4 0.50 168,607 25 2544 30D155116 121 0.1 5 17.1 0.78 9,028 25 2545 30D155101 121 0.1 6 18.0 0.74 12,509 25 2546 30D155102 121 0.1 5 18.6 0.71 11,345 25 2547 30D155103 103 0.1 6 16.8 0.62 42,426 25 2591 30D155301 -195 * 13 —— ——— I 25 2592 30D155302 -168 * 13 ——— —— I 25 2593 30D155303 -169 * 13 —— —— I 25 2594 30D155304 -173 * 13 —— I 25 4445 30D155130 -103 10 4 — — 28,562 25 4446 30D155130 -103 10 4 — — 45,437 25 4447 30D155132 -103 10 4 —— --- 44,837 25 4448 30D155133 -90 10 7 -- - -- - 150,426 25 4449 30D155134 -90 10 8 —— — 142,051 25 4450 30D155135 -90 10 6 — — 269,359 25 4451 30D155136 -83 10 10 — — 530,475 25 MATERIAL 40D155 Lay-up = [±40]3 ,Vf = 0.40, Ave. thickness = 3.17 mm, S.D. = 0.09 mm, CoRezyn 63-AX-051 Polyester 2504 40D155110 147 2505 40D155105 142 2506 40D155102 142 2516 40D155103 86 13 11.5 14 I 25 13 11.2 16 I 25 13 11.4 11 I 25 4 10.8 0.89 7,598 250.1 394 TEST & MAX. R SAMPLE ID # STRESS MPa 2517 40D155104 86 0.1 2518 40D155106 86 0.1 2519 40D155107 69 0.1 2520 40D155108 55 0.1 2521 40D155109 55 0.1 2522 40D155111 69 0.1 2523 40D155112 69 0.1 2524 40D155113 55 0.1 2595 40D155301 -131 * 2596 40D155302 -135 * 2597 40D155303 -127 * 2598 40D155304 -134 * 4452 40D155137 -103 10 4453 40D155136 -90 10 4454 40D155135 -90 10 4455 40D155134 -90 10 4456 40D155133 -69 10 4457 40D155132 -69 10 4458 40D155131 -69 10 4459 40D155140 -59 10 4467 40D155141 -59 10 MATERIAL 45D155 Lay-up = [±45]3,Vf = 0.38, Ave. thickness 2441 45D155112 106 * 2442 45D155105 107 * 2443 45D155108 108 * 2444 45D155104 55 0.1 2445 45D155106 55 0.1 2446 45D155113 41 0.1 2447 45D155111 55 0.1 2448 45D155110 41 0.1 2449 45D155102 34 0.1 2450 45D155107 41 0.1 2451 45D155114 69 0.1 2452 45D155109 69 0.1 2453 45D155103 69 0.1 2599 45D155301 -139 * 2600 45D155302 -135 * 2601 45D155303 -135 * 2602 45D155304 -142 * 4399 45D155140 -97 10 4400 45D155143 -69 10 4401 45D155141 -69 10 4402 45D155142 -69 10 4403 45D155149 -69 10 4404 45D155145 34 -I 4405 45D155148 34 -I E e CYCLES WIDTH GPa % TO FAIL (mm) and Notes 11.8 0.97 6,950 25 12.2 0.93 3,054 25 11.7 0.69 27,264 25 12.3 0.46 631,703 25 11.9 0.49 275,777 25 11.8 0.67 36,776 25 12.0 0.62 34,920 25 11.1 0.52 857,164 25 — — I 25 — — I 25 — — I 25 — — I 25 — — 635 25 — — — 5,021 25 — — 4,073 25 — — 2,494 25 — — 60,384 25 — — 82,612 25 — — 129,706 25 — — 460,369 25 — — 611,713 25 SD .= 0.06 mm, CoRezyn 63-AX-051 Polyester 9.66 22.0 I 25 10.3 24.9 I 25 9.97 24.0 I 25 10.2 0.65 12,908 25 9.55 0.68 15,899 25 10.4 0.41 394,632 25 9.91 0.64 10,671 25 9.33 0.43 748,125 25 9.10 0.38 2,167,690 25 R 10.6 0.42 507,811 25 9.06 0.92 1,885 25 9.65 0.97 1,639 25 9.40 0.99 3,669 25 — — I 25 — — I 25 — — I 25 — — I 25 — — 1,236 25 — — 523,409 25 — — 597,040 25 — — 362,225 25 ---- — 367,979 25 ---- — 153,354 25 — — 64,588 25 Q Hz 4 4 5 12 15 5 8 20 13 13 13 13 2 4 4 4 6 6 6 10 10 3.17 mm, 13 13 13 12 10 15 10 20 20 12 2 2 2 13 13 13 13 2 5 10 10 10 5 5 3 9 5 4406 45D155144 34 -I 5 — —— 114,603 25 4407 45D155146 -83 10 8 ——— —— 19,588 25 4408 45D155147 -83 10 5 — ——— 34,052 25 4409 45D155120 -83 10 5 —— ——— 28,684 25 4410 45D155119 -97 10 2 ——— —— 3,655 25 4411 45D155115 -97 10 2 —— —— 4,822 25 4412 45D155121 28 -I 10 ——— ——— 705,984 25 4413 45D155116 28 -I 10 — — 791,693 25 4414 45D155164 41 -I 2 ——— —— 12,406 25 4415 45D155160 41 -I 2 — —— 10,061 25 4416 45D155161 41 -I 2 — — 19,692 25 MATERIAL 45D155V2 Lay-up = [±45]3 ,Vf = 0.38, Ave. thickness = 3.10 mm, S.D. = 0.10 mm, Derakane 8084 Epoxy Vinyl ester 4 417 4 5D 1 5 5V 3 4 9 -69 10 12 ———— ———— 2 ,5 6 9 ,2 2 7 25 4 418 4 5D 1 5 5V 3 2 2 -83 10 5 ——— ———— 148 ,697 25 4 419 4 5D 1 5 5V 3 2 6 -83 10 5 -------— ———— 82 ,1 4 3 25 4 4 2 0 4 5D 1 5 5V 3 4 4 -83 10 5 ———— ———— 2 6 7 ,2 2 6 25 4421 4 5D 1 5 5V 3 2 0 -69 10 10 —------- ——— 1 ,7 0 0 ,1 1 6 25 4 4 2 2 4 5D 1 5 5V 3 2 5 -69 10 12 — ———— 1 ,1 5 4 ,4 1 4 25 4423 4 5D 1 5 5V 3 3 0 -151 * 13 ——— —— — I 25 4 4 2 4 4 5D 1 5 5V 3 2 9 -1 48 * 13 — —— ———- I 25 4 425 4 5D 1 5 5V 3 3 1 -1 49 * 13 ———— —— — I 25 4 4 2 6 4 5D 1 5 5V 3 1 4 136 * 13 9 .9 ——— I 25 4 4 2 7 4 5D 1 5 5V 3 1 3 129 * 13 10 .6 ——— I 25 4 4 2 8 4 5D 1 5 5V 3 1 6 141 * 13 11 .0 ———— I 25 4 4 2 9 4 5D 1 5 5V 3 1 5 48 0.1 5 10.1 0 .5 3 1 3 7 ,9 3 2 25 4 4 3 0 451)15537311 48 0.1 5 ———— —— — 2 6 2 ,3 8 8 25 4431 4 5D 155V 301 48 0.1 5 10 .9 0 .4 9 321 ,8 9 1 25 4 4 3 2 4 5D 1 5 5V 3 0 4 55 0.1 5 ———— ———— 2 7 ,6 0 6 25 4 433 4 5D 1 5 5V 3 0 3 41 0.1 10 9 .5 0 .51 7 7 0 ,7 5 9 25 4 4 3 4 4 5D 1 5 5V 3 0 2 41 0.1 10 9 .5 0 .5 0 1 ,2 3 3 ,5 8 0 25 4 435 4 5D 1 5 5V 3 1 0 41 0.1 10 10 .6 0 .4 4 1 ,2 8 9 ,6 4 7 25 4 4 3 6 4 5D 155V 161 -69 10 10 — — 4 ,9 7 5 ,5 0 0 25 R MATERIAL 45D155P2 Lay-up = [±45]3 ,Vf = 0.40, Ave. thickness = 3.05 mm, S.D. = 0.02 mm, CoRezyn 75-AQ-010 Isopolyester 4622 IS045114 55 0.1 3 11.9 0.57 4,934 25 4623 ISO45101 55 0.1 2 10.9 0.63 5,740 25 4624 ISO45102 41 0.1 5 11.7 0.39 202,047 25 4625 ISO45103 41 0.1 5 11.3 0.42 192,822 25 4626 IS045111 41 0.1 5 11.5 0.40 179,293 25 4627 ISO45110 38 0.1 7 11.3 0.37 811,700 25 4628 IS045112 55 0.1 2 11.8 0.58 6,965 25 4629 ISO45109 48 0.1 3 -------— — —— 21,334 25 4630 ISO45108 48 0.1 2 10.8 0.54 17,395 25 4631 ISO45107 48 0.1 2 —— — ——— 9,479 25 4632 ISO45106 38 0.1 4 10.8 0.41 422,361 25 4633 ISO45105 95 * 13 12.0 1.30 I 25 4634 ISO45104 97 * 13 12.0 1.35 I 25 396 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes 4635 IS045113 96 * 13 11.3 1.4 I 25 4636 IS045119 -156 * 13 ———— ———— I 25 4637 IS045116 -165 * 13 - —— ———— I 25 4638 IS045115 -158 * 13 ———— —— — I 25 4639 IS045117 -161 MATERIAL 45D155 V * 13 I 25 Lay-up = [45]3, Vf = 0.40, Ave. thickness = 3.00 mm, S.D. = 0.07 mm, Derakane 411C-50 vinyl ester 4869 41145113 41.4 0.1 10 10.2 0.40 4,000,000 25 R 4870 41145101 69 0.1 10.5 0.84 4,581 25 4871 41145109 130 * 13 10.8 21 I 25 4872 41145106 118 * 13 10.1 15 I 25 4873 41145107 116 * 13 10.5 23 I 25 4874 41145105 55.2 0.1 3 10.5 0.64 38,539 25 4875 41145104 55.2 0.1 4 10.8 0.61 51,501 25 4876 41145102 55.2 0.1 3 11.4 0.60 62,968 25 4877 41145110 69 0.1 2 11.2 0.86 7,247 25 4879 41145112 69 0.1 2 ——— ———— 6,339 25 5908 41145116 -155 * 13 ———— ———— I 25 5909 41145115 -153 * 13 ———— ——— I 25 5910 41145119 -154 * 13 ———— ———— I 25 5911 41145118 MATERIAL 50D 155 -154 * 13 I 25 Lay-up = [±50]3 ,Vf = 0.39, Ave. thickness = 3.23 mm, S.D. = 0.11 mm, CoRezyn 63-AX-051 Polyester 2454 50D155114 67 * 13 8.33 20 I 25 2455 50D155113 67 * 13 8.39 19 I 25 2456 50D155107 63 * 13 8.43 17 I 25 2457 50D155104 35 0.1 20 8.62 0.41 136,803 25 2458 50D155116 35 0.1 15 9.00 0.41 72,943 25 2459 50D155115 35 0.1 15 8.32 0.42 96,273 25 2460 50D155111 28 0.1 15 8.11 0.36 1,855,523 25 2461 50D155106 41 0.1 5 8.81 0.48 11,555 25 2462 50D155108 41 0.1 7 8.74 0.52 11,608 25 2463 50D155112 41 0.1 4 8.90 0.53 11,509 25 2464 50D155105 28 0.1 15 8.42 0.37 1,159,160 25 2465 50D155101 58 * 13 8.43 30.0 I 25 2466 50D155102 67 * 13 9.52 22.2 I 25 2603 50D155301 -132 * 13 —— — ———— I 25 2604 50D155302 -142 * 13 ——— ——— I 25 2605 50D155303 -139 * 13 —— — ———— I 25 2606 50D155304 -138 * 13 —— ———— I 25 4468 50D155134 -90 10 3 ———— ——— 10,617 25 4469 50D155133 -90 10 3 ———— 9,472 25 4470 50D155132 -90 10 3 ———— ———— 11,783 25 4471 50D155131 -69 10 8 — — 2,313,976 25 397 TEST & SAMPLE ID # MAX. STRESS MPa R Q Hz E GPa e % CYCLES TO FAIL WIDTH (mm) and Notes 4472 50D155135 -79 10 4 ———— ———— 38,964 25 4473 50D155136 -76 10 4 — ———— 128,196 25 4613 50D155137 -79 10 4 — —— ———— 83,779 25 4619 50D155145 -100 10 2 — — — 2,213 25 MATERIAL 60D155 Lay-up = [±60]3 ,Vf = 0.40, Ave. thickness = 3.11 mm, S.D. =0.14 mm, CoRezyn 63-AX-051 Polyester 2482 60D155103 37 * 13 7.02 0.65 I 25 2483 60D155106 34 * 13 7.04 0.65 I 25 2484 60D155101 36 * 13 7.44 0.62 I 25 2576 60D155146 40 * 13 7.99 0.60 I 25 2548 60D155108 24 0.1 10 8.00 0.31 23,872 25 2549 60D155115 24 0.1 15 8.33 0.32 35,211 25 2550 60D155113 24 0.1 10 8.26 0.32 17,122 25 2551 60D155104 21 0.1 20 7.81 0.27 160,347 25 2552 60D155105 21 0.1 15 8.30 0.25 369,336 25 2553 60D155109 28 0.1 4 8.20 0.38 4,716 25 2554 60D155107 28 0.1 5 7.75 0.37 3,715 25 2555 60D155110 28 0.1 5 7.23 0.36 2,270 25 2556 60D155116 19 0.1 15 7.24 0.25 1,915,213 25 2557 60D155102 21 0.1 10 7.33 0.27 217,771 25 2607 60D155301 -144 * 13 ———— ———— I 25 2608 60D155302 -133 * 13 ———— ——— I 25 2609 60D155303 -143 * 13 ———— ———— I 25 2610 60D155304 -144 * 13 ———— ———— I 25 4437 60D155162 -103 10 4 ———— ——— 2,461 25 4438 60D155141 -103 10 4 -------— ———— 1,786 25 4439 60D155166 -103 10 4 ———— — 4,011 25 4440 60D155160 -86 10 6 — —- ——— 19,416 25 4441 60D155165 -86 10 6 ———— — 21,746 25 4442 60D155142 -86 10 6 ———— — 33,065 25 4443 60D155114 -79 10 10 — — 573,969 25 4444 60D155164 MATERIAL 70D155 -79 10 10 434,136 25 Lay-up = [±70]3 ,Vf = 0.40%, Ave. thickness = 3.17 mm, S.D. = 0.04 mm, CoRezyn 63-AX-051 Polyest 2485 70D155101 28 * 13 6.67 0.49 I 25 2486 70D155104 27 * 13 6.86 0.46 I 25 2487 70D155107 26 * 13 6.51 0.44 I 25 2577 70D155141 30 * 13 7.51 0.49 I 25 2525 70D155111 17 0.1 10 7.84 0.21 30,672 25 2526 70D155109 17 0.1 12 8.16 0.19 51,196 25 2527 70D155106 17 0.1 12 7.90 0.23 43,825 25 2528 70D155110 14 0.1 20 7.31 0.19 1,045,443 25 2529 70D155108 17 0.1 15 7.14 0.28 27,455 25 2530 70D155103 16 0.1 20 7.47 0.20 296,781 25 398 TEST & SAMPLE ID # MAX. STRESS MPa R Q Hz E GPa e % CYCLES TO FAIL WIDTH (mm) and Notes 2531 70D155102 19 0.1 5 7.09 0.27 8,217 25 2532 70D155134 19 0.1 5 7.21 0.26 10,888 25 2533 70D155123 19 0.1 5 7.19 0.27 27,256 25 2534 70D155121 16 0.1 15 6.66 0.24 246,630 25 2535 70D155122 16 0.1 15 7.17 0.22 421,514 25 2611 70D155301 -133 * 13 — —— —— — I 25 2612 70D155302 -136 * 13 ———— ———— I 25 2613 70D155303 -138 * 13 ———— —— — I 25 2614 70D155304 -138 * 13 ———— — — I 25 MATERIAL 80D155 Lay-up = [±80]3 ,Vf = 0.38, Ave. thickness = 3.32 mm, S.D. = 0.10 mm, CoRezyn 63-AX-051 Polyester 2488 80D155105 27 * 13 7.79 0.38 I 25 2489 80D155103 25 * 13 7.00 0.34 I 25 2490 80D155101 24 * 13 7.05 0.37 I 25 2578 80D155141 27 * 13 7.75 0.38 I 25 2580 80D155201 26 * 13 9.30 0.30 I 25 2581 80D155202 26 * 13 8.15 0.34 I 25 2582 80D155203 27 * 13 8.65 0.34 I 25 2494 80D155120 26 * 13 6.95 0.35 I 25 2495 80D155122 24 * 13 6.43 0.35 I 25 2491 80D155102 17 0.1 2 7.59 0.24 2,096 25 2492 80D155112 17 0.1 2 6.79 0.25 865 25 2493 80D155104 17 0.1 2 7.35 0.24 3,673 25 2496 80D155121 12 0.1 25 7.49 0.15 8,000,000 25 R 2497 80D155106 16 0.1 5 8.42 0.19 34,973 25 2498 80D155109 16 0.1 15 7.02 0.20 16,756 25 2499 80D155111 16 0.1 10 7.81 0.20 24,111 25 2500 80D155123 14 0.1 10 7.42 0.18 135,541 25 2501 80D155145 14 0.1 10 7.06 0.18 261,230 25 2502 80D155146 14 0.1 10 7.20 0.18 186,407 25 2619 80D155205 -148 * 13 —— ———— I 25 2620 80D155206 -146 * 13 ———— ——— I 25 2621 80D155207 -156 * 13 ——— — — I 25 2622 80D155208 -162 * 13 —— — ——— I 25 MATERIAL 90D155 Lay-up = [±90]3,Vf = 0.38, Ave. thickness = 3.32 mm, S.D. = 0.12 mm, CoRezyn 63-AX-051 Polyester 2467 90D155105 27 * 13 7.21 0.38 I 25 2468 90D155110 26 * 13 7.30 0.34 I 25 2469 90D155104 24 * 13 6.44 0.34 I 25 2579 90D155141 29 * 13 9.04 0.34 I 25 2470 90D155101 17 0.1 5 7.23 0.24 17,903 25 2471 90D155102 17 0.1 5 7.60 0.24 22,344 25 2472 90D155103 17 0.1 5 7.00 0.25 27,113 25 2473 90D155107 14 0.1 15 7.31 0.17 612,541 25 399 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS Hz GPa % TO FAIL (mm) ID # 2474 90D155108 MPa 19 0.1 2 7.62 0.25 783 and Notes 25 2475 90D155113 19 0.1 2 7.58 0.24 1,800 25 2476 90D155109 19 0.1 2 7.05 0.25 1,179 25 2477 90D155125 14 0.1 20 6.97 0.20 1,190,051 25 2578 90D155130 14 0.1 20 7.45 0.19 1,712,400 25 2479 90D155120 28 * 13 7.50 0.41 I 25 2480 90D155122 28 * 13 7.24 0.40 I 25 2481 90D155121 27 * 13 6.89 0.40 I 25 2623 90D155112 -108 * 13 — — I 25 2624 90D155111 -129 * 13 ——— —— I 25 2625 90D155301 -126 * 13 --— —— I 25 2626 90D155302 -128 * 13 ——— —— I 25 4614 90D155139 -66 10 15 — --— 20,000,000 25 R 4615 90D155130 -90 10 5 —— —— 39,215 25 4616 90D155131 -79 10 8 — —— 400,785 25 4617 90D155132 -79 10 10 — ——— 515,123 25 4618 90D155133 -79 10 10 — —— 780,009 25 R 4620 90D155134 -90 10 5 — — 27,023 25 4621 90D155139 -90 10 5 — — 26,104 25 MATERIAL 90D155V2 Lay-up = [90]6, Vf = 0.38, Ave. thickness = 3.31 mm, S.D. = 0.09 mm, Derakane 8084 vinyl ester 4760 808490207 17.2 0.1 15 8.72 0.20 2,000,000 25 R 4761 808490213 51.1 * 13 9.32 0.56 I 25 4762 808490211 34.5 0.1 2 8.61 0.41 1,486 25 4763 808490215 27.6 0.1 2 9.32 0.32 85,350 25 4764 808490214 20.7 0.1 5 9.12 0.23 248,600 25 4765 808490212 20.7 0.1 7 8.76 0.24 153,624 25 4766 808490209 20.7 0.1 10 8.74 0.24 2,163,003 25 4767 808490208 27.6 0.1 5 9.38 0.30 10,162 25 4768 808490206 27.6 0.1 5 8.70 0.33 19,542 25 4769 808490216 34.5 0.1 I 8.42 0.41 422 25 4770 808490202 34.5 0.1 I 8.25 0.43 548 25 4771 808490217 55.8 * 13 9.66 0.58 I 25 4772 808490201 52.0 S 13 8.09 0.64 I 25 5912 808490218 -175 * 13 ——— I 25 5913 808490219 -172 * 13 —— —— I 25 5914 808490221 -172 * 13 ——— — I 25 5915 808490200 -166 * 13 —— —— I 25 MATERIAL 90D155V Lay-up = [90]6, Vf = 0.40, Ave. thickness = 2.98 mm, S.D. = 0.10 mm, Derakane 411C-50 vinyl ester 4776 41190130 43.8 * 13 7.63 0.40 I 25 4777 41190140 51.2 * 13 9.81 0.52 I 25 4778 41190136 52.8 * 13 10.3 0.51 I 25 4779 41190141 20.7 0.1 10 11.8 0.19 223,965 25 400 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes 4780 41190131 20.7 0.1 8 13.0 0.19 184,528 25 4781 41190149 20.7 0.1 10 11.1 0.19 138,110 25 4782 41190148 27.6 0.1 5 9.42 0.31 2,730 25 4783 41190135 27.6 0.1 5 10.8 0.26 15,581 25 4784 41190134 27.6 0.1 4 10.1 0.28 12,939 25 4785 41190147 24.1 0.1 5 8.21 0.31 77,719 25 4786 41190146 24.1 0.1 8 11.8 0.25 52,833 25 4787 41190138 24.1 0.1 4 10.1 0.24 30,181 25 4788 41190137 17.2 0.1 15 10.3 0.17 2,000,000 25 R 5916 41190145 -173 * 13 — ———— I 25 5917 41190144 -164 * 13 - - — ———— I 25 5918 41190132 -173 * 13 --------- ———— I 25 5919 41190139 -158 MATERIAL 90D155E2 * 13 I 25 Lay-up = [90]6, Vf = 0.38, Ave. thickness = 3.41 mmi, S.D. = 0.20 mm, SC 14 epoxy 4789 SC 1490216 27.6 0.1 0.1 9.29 0.35 254 25 4790 SC 1490215 20.7 0.1 0.1 5.48 0.40 1,161 25 4791 SC 1490207 38.2 * 13 6.72 0.57 I 25 4792 SC 1490204 39.8 * 13 7.20 0.55 I 25 4793 SC 1490208 43 * 13 8.34 0.52 I 25 4794 SC 1490206 13.8 0.1 15 9.10 0.15 3,000,000 25 R 4795 SC 1490209 20.7 0.1 3 5.30 0.40 8,141 25 4796 SC 1490213 17.2 0.1 5 7.30 0.26 292,196 25 4797 SC 1490210 20.7 0.1 3 8.06 0.27 27,984 25 4798 SC 1490212 26.1 0.1 3 5.93 0.44 402 25 5904 SC 1490211 -151 * 13 ———— ———— I 25 5905 SC 1490201 -153 * 13 —— — ———— I 25 5906 SC 1490203 -151 * 13 — —— ———— I 25 5907 SC 1490205 -151 * 13 ———— ——— I 25 MATERIAL ROVl (0/90 ROVING) Lay-up = [0/90]7 ,Vf = 0.46, Ave. thickness = 2.96 mm, S.D. = 0.16 mm, CoRezyn 63-AX-051 Polyester. Tests 2095 - 2108 in this section were done for Table 10. Compression tests involved a 13 mm gage length. 2094 ROVOl 380 * 0.25 22.8 2.40 I ZERO 2095 ROV02 364 * 0.25 22.5 2.20 I ZERO 2096 ROV03 374 * 0.25 24.8 2.20 I ZERO 2097 ROV04 97 * 0.25 11.0 ——- I ±45 2098 ROV05 102 * 0.25 11.4 — I ±45 2099 ROV06 99 * 0.25 11.4 —- I ±45 2100 ROV07 -213 * 0.25 20.3 —— I ZERO 2101 ROV08 -230 * 0.25 21.6 ——— I ZERO 2102 ROV09 -240 * 0.25 23.9 — I ZERO 2103 ROVlO 98 * 0.25 10.6 — I ±45 2104 ROVll -100 * 0.25 11.2 --— I ±45 2105 ROV12 -97 * 0.25 11.3 —— I ±45 4 0 1 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes 2106 ROV50 -207 * 0.25 13.7 ——— I ZERO 2107 ROV51 410 * 0.25 25.4 ——— I ZERO 2108 ROV52 102 * 0.25 13.9 — I ±45 MATERIAL ROV2 (0/90 ROVING) Lay-up = [0/90]4,Vf = 0.30, Ave. thickness = 4.08 mm, S.D. = 0.10 mm, CoRezyn 63-AX-051 Polyester 4193 ROV217 326 * 13 I 25 4194 ROV215 103 0.1 10 — — 3,200,000 25 R 4195 ROV218 380 * 13 21.0 1.9 I 25 4196 ROV206 381 * 13 21.6 1.8 I 25 4197 ROV205 241 0.1 I 21.3 1.45 1,642 25 4198 ROV201 172 0.1 3 21.7 0.96 13,794 25 4199 ROV200 138 0.1 5 21.2 0.74 608,189 25 4200 ROV204 172 0.1 2 22.4 0.87 40,071 25 4201 ROV203 172 0.1 3 23.1 0.89 63,917 25 4202 ROV214 138 0.1 10 21.2 0.78 723,201 25 4203 ROV212 138 0.1 10 21.0 0.81 483,611 25 4204 ROV207 241 0.1 I 20.9 1.50 1,043 25 4205 ROV219 241 0.1 I 20.7 1.58 494 25 4226 ROV231 -266 * 13 ———— ——— I 25 4227 ROV230 -245 * 13 —— — ——— I 25 4228 ROV232 -217 * 13 —— —— I 25 4229 ROV238 -247 * 13 — — I 25 MATERIAL ROV 3 (0/90 ROVING) Lay-up = [0/90]5 ,Vf = 0.40, Ave. thickness = 3.15 mm, S.D. = 0.05 mm, CoRezyn 63-AX-051 Polyester 4284 ROV3106 406 * 13 21.1 2.3 I 25 4285 ROV3109 443 * 13 21.4 2.4 I 25 4286 ROV3103 416 * 13 21.0 2.3 I 25 4287 ROV3107 207 0.1 2 20.1 1.35 3,055 25 4288 ROV3112 207 0.1 2 21.5 1.26 8,236 25 4289 ROV3108 207 0.1 3 20.9 1.34 3,720 25 4290 ROV3114 172 0.1 4 20.0 1.10 23,506 25 4291 ROV3110 172 0.1 4 20.2 1.06 14,233 25 4292 ROV3111 172 0.1 4 20.7 1.03 28,712 25 4293 ROV3102 103 0.1 10 21.2 0.58 4,320,474 25 4294 ROV3113 138 0.1 6 19.9 0.85 351,549 25 4295 ROV3115 138 0.1 6 22.0 0.79 690,805 25 4296 ROV3104 138 0.1 6 21.1 0.80 216,248 25 4297 ROV3101 138 0.1 6 20.7 0.84 264,008 25 4314 ROV3130 -201 * 13 ———— ———— I 25 4315 ROV3131 -204 * 13 ———— ———— I 25 4316 ROV3132 -204 * 13 — ———— I 25 4320 ROV3105 103 0.1 10 21.7 0.61 4,855,537 25 4327 ROV3130 103 0.1 8 21.0 0.63 5,981,053 25 402 TEST & SAMPLE ID # MAX. R Q E e CYCLES WIDTH STRESS MPa Hz GPa % TO FAIL (mm) and Notes MATERIAL ROV4 (0/90 ROVING) Lay-up = [0/90]6,Vf = 0.53, Ave. thickness = 3.71 mm, S.D. = 0.09 mm, CoRezyn 63-AX-051 Polyester 4298 ROV4109 207 0.1 2 27.5 1.04 1,501 25 4299 ROV4110 207 0.1 2 28.1 1.05 1,558 25 4300 ROV4111 207 0.1 2 26.4 1.11 2,319 25 4301 ROV4106 172 0.1 3 28.1 0.83 4,371 25 4302 ROV4105 172 0.1 3 24.4 0.98 3,514 25 4303 ROV4114 172 0.1 3 26.8 0.90 4,498 25 4304 ROV4115 138 0.1 5 27.0 0.67 14,689 25 4305 ROV4107 138 0.1 5 28.1 0.65 8,459 25 4306 ROV4113 138 0.1 5 27.2 0.67 11,994 25 4307 ROV4112 103 0.1 6 25.1 0.51 68,112 25 4308 ROV4104 502 * 13 25.3 2.2 I 25 4309 ROV4108 524 * 13 24.3 2.4 I 25 4310 ROV4102 488 * 13 25.4 2.1 I 25 4311 ROV4117 103 0.1 5 28.0 0.47 76,081 25 4312 ROV4116 103 0.1 5 27.7 0.46 147,753 25 4313 ROV4103 86 0.1 15 26.7 0.36 1,965,313 25 4317 ROV4130 -351 * 13 ———— ——— I 25 4318 ROV4131 -302 * 13 ———— ———— I 25 4319 ROV4132 -289 * 13 ———— ———— I 25 4321 ROV4101 86 0.1 15 26.9 0.35 924,136 25 4324 ROV4120 86 0.1 10 27.2 0.36 273,658 25 4326 ROV4121 86 0.1 5 27.1 0.35 1,135,918 25 HIGH CYCLE FATIGUE DATABASE 4 0 3 The High Cycle Fatigue Database studied two basic composite materials, a (O)2 and a (90)4 laminate, at R values of 2, 10, -I, 0.1 and 0.5. The Fatigue tests were carried out to 100 million cycles and involved testing frequencies up to 100 Hz. Smaller and thinner composites were necessary to avoid thermal failures. It 60 mm - - - - - - - - - - - - - - - - - H / R a d i u s h ~ G a g e L e n g t h — H Gage Length, Radius and Width of [0]2 and [90]4 Test Coupons in the High Cycle Database Direction and R value Gage Length Radius Width [0] R = 2, 10 5 mm No radius 6 mm [90] R = 2, 10, -I 5 mm 19 mm [90] R = 0.1, 0.5 25 mm 19 mm [0] R = 0.1, 0.5 10 mm 17 mm 6 mm [0] R = - I 5 mm TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes MATERIAL (O)2 Lay-up = (O)2 ,Vf = 0.48 - 0.52, Average Thickness (Non-Tapered Coupons) = 0.82 mm, S.D. = 0.05 mm (min = 0.71 mm, max = 0.89 mm), Knytex D155 Fabric (527 g/m2), CoRezyn 63-AX-051 Polyester 5001 CT4 1627 * 6 46.2 3.53 I 6 tab 5002 AT2 1517 * 6 46.2 3.28 I 6 tab 5003 AT26 1393 * 3 46.2 3.01 I 6 tab 5004 CT3 1344 * 0.01 46.2 2.91 I 6 tab 5146 TF514 1332 * 5 39 2.88 I 6 tab 5147 TF510 1249 * 0.1 39 2.70 I 6 tab 5148 TF504 1398 * 5 39 3.03 I 6 tab 5149 TF505 1329 * 5 39 2.88 I 6 tab 5150 TF501A 1274 * 5 39 2.76 I 6 tab 5151 TF502A 1589 * 5 39 3.43 I 6 tab 5152 TF503A 1496 * 5 39 3.23 I 6 tab 5153 TF510 1249 * 5 39 2.70 I 6 tab 5154 AT5 1270 * 0.5 46.2 2.75 I 6 tab 5155 AT4 1343 * 0.5 46.2 2.91 I 6 tab 5156 Tl 1684 * 5 46.2 3.64 I 6 tab 5157 TFT5 1692 * 5 39 3.66 I 6 tab 5158 TF501 1713 * 5 39 3.70 I 6 tab 5159 TF502 1391 * 5 39 3.01 I 6 tab 404 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS Hz GPa % TO FAIL (mm) ID # MPa and Notes 5005 AT27 690 0.1 20 46.2 1.49 2,982 6 tab 5006 CTl 690 0.1 20 46.2 1.49 45,845 6 tab 5007 ATI 9 469 0.1 60 46.2 1.01 157,502 6 tab 5008 ATI 8 469 0.1 60 46.2 1.01 702,844 6 tab 5009 AT23 414 0.1 80 46.2 0.90 602,984 6 tab 5010 AT20 414 0.1 80 46.2 0.90 2,269,945 6 tab 5011 CT5 310 0.1 100 46.2 0.67 5,902,329 6 tab 5012 C T I 310 0.1 100 46.2 0.67 78,810,903 6 R tab 5013 C T l 310 0.1 100 46.2 0.67 110,539,817 6 R tab 5160 Tl 345 0.1 60 46.2 0.60 5,151,390 6 tab 5161 T2 345 0.1 40 46.2 0.60 772,447 6 tab 5162 FT6 538 0.1 60 46.2 1.16 144,728 6 tab 5163 TF503 345 0.1 60 46.2 0.75 6,889,310 6 R tab 5164 TF506 538 0.1 60 46.2 1.16 891,716 6 tab 5165 AT3 207 0.1 100 46.2 0.45 14,715,704 6 R tab 5166 AT21 414 0.1 80 46.2 0.90 80,439 6 tab 5167 AT22 414 0.1 80 46.2 0.90 98,566 6 tab 5014 TF513 1310 * 5 39.2 3.31 I 6 tab 5015 TF512 1426 * 5 39.2 3.64 I 6 tab 5016 TF515 1396 * 5 39.2 3.56 I 6 tab 5017 TF516 1295 * 20 39.2 3.34 I 6 tab 5018 TF525 602 0.5 60 39.2 1.54 235,881 6 tab 5019 TF526 602 0.5 60 39.2 1.54 284,150 6 tab 5168 TF524 602 0.5 40 39.2 1.54 2,513,501 6 tab 5020 TF527 606 0.5 60 39.2 1.54 850,428 6 tab 5021 TF521 535 0.5 80 39.2 1.36 417,082 6 tab 5022 TF528 535 0.5 80 39.2 1.36 1,095,381 6 tab 5023 TF522 535 0.5 80 39.2 1.36 4,112,276 6 tab 5169 TF517 535 0.5 60 39.2 1.36 486,856 6 tab 5170 TF518 535 0.5 60 39.2 1.36 368,725 6 tab 5024 TF529 468 0.5 100 39.2 1.19 11,927,857 6 tab 5025 TF520 468 0.5 100 39.2 1.19 16,711,593 6 tab 5026 TF519 401 0.5 100 39.2 1.02 100,686,430 6 R tab 5171 TF507 717 0.5 40 39.2 1.82 474,816 6 tab 5172 TF508 627 0.5 60 39.2 1.60 11,276,771 6 tab 5173 TF504A 807 0.5 40 39.2 2.06 245,223 6 tab 5174 TF505A 627 0.5 60 39.2 1.60 3,527,508 6 tab Brackets after the sample ID indicate the coupon fiber volume in the radius 5027 AC 14 (57) -742 * 0.8 35.6 -2.09 I 6 tab 5028 AC 17 (46) -741 * 0.8 35.6 -2.09 I 6 tab 5029 ACl3 (45) -683 * 0.8 35.6 -1.93 I 6 tab 5030 AC ll (48) -414 10 40 35.6 -1.17 8,226 6 tab 5031 AC 12 (49) -414 10 40 35.6 -1.17 10,886 6 tab 5032 AC8 (61) -414 10 40 35.6 -1.17 19,210 6 tab 5033 AC15 (61) -345 10 60 35.6 -0.97 337,992 6 tab 5034 AC 16 (46) -345 10 60 35.6 -0.97 375,478 6 tab 5035 AC7 (50) -345 10 60 35.6 -0.97 587,407 6 tab 5036 AC30 (48) -276 10 100 35.6 -0.78 103,112,335 6 R tab 5037 AClO (51) -276 10 100 35.6 -0.78 103,573,682 6 R tab 5175 AC2 -414 10 40 35.6 -1.17 2,688 6 tab 405 TEST & MAX. R SAMPLE STRESS ID # 5176 ACl MPa -345 10 5177 C2A -264 10 5178 C6 -207 10 5179 7A -207 10 5180 WAl -276 10 5181 WA4 -276 10 5182 WA5 -345 10 5183 WAlO -276 10 5184 CC3 -345 10 5185 CC4 -345 10 5186 CC5 -379 10 5187 CC6 -379 10 5188 C C l -379 10 5189 CCS -379 10 5190 CC9 -379 10 5191 CClO -379 10 5192 CCll -379 10 5193 CC12 -379 10 5194 CC12A -379 10 5195 C2 -345 10 5196 FCl -234 10 5038 AC 19 (49) -552 2 5039 AC26 (49) -552 2 5040 AC29 (49) -552 2 5041 AC20 (51) -552 2 5042 AC21 (47) -483 2 5043 AC24 (52) -483 2 5044 AC31 (44) -483 2 5045 AC22 (46) -483 2 5046 AC32 (46) -448 2 5047 AC35 (48) -448 2 5048 AC25 (49) -448 2 5049 AC23 (50) -414 2 5197 AC34 -448 2 5198 AC33 -448 2 5199 AC32 -448 2 5050 TCTl 1367 * 5051 TCT2 1387 * 5052 TCT3 1279 * 5053 TCT4 1527 * 5054 TCCl -646 * 5055 TCC2 -463 * 5056 TCC3 -689 * 5057 TCC4 -537 * 5200 OSTCl -481 * 5201 0STC3 -478 * 5202 OFTCl -513 * 5203 0FTC2 -534 * 5204 AC36 -592 * E e CYCLES WIDTH GPa % TO FAIL (mm) and Notes 35.6 -0.97 76,726 6 tab 35.6 -0.74 13,990,000 6 tab 35.6 -0.58 51,028,261 6 R tab 35.6 -0.58 10,188,704 6 R tab 35.6 -0.78 12,635,375 6 R tab 35.6 -0.78 9,707,898 6 R tab 35.6 -0.97 52,740 6 tab 35.6 -0.78 10,106,247 6 tab 35.6 -0.97 69,631 6 tab 35.6 -0.97 781,804 6 tab 35.6 -1.06 4,021 6 tab 35.6 -1.06 496,674 6 tab 35.6 -1.06 12,660 6 tab 35.6 -1.06 3,638,153 6 tab 35.6 -1.06 4,765 6 tab 35.6 -1.06 8,349 6 tab 35.6 -1.06 1,336,317 6 tab 35.6 -1.06 10,192 6 tab 35.6 -1.06 6,550 6 tab 35.6 -0.97 37,274 6 tab 35.6 -0.66 23,110,567 6 tab 35.4 -1.56 9,255 6 tab 35.4 -1.56 12,319 6 tab 35.4 -1.56 22,071 6 tab 35.4 -1.56 46,085 6 tab 35.4 -1.36 11,347 6 tab 35.4 -1.36 38,158 6 tab 35.4 -1.36 45,312 6 tab 35.4 -1.36 103,970 6 tab 35.4 -1.26 17,937 6 tab 35.4 -1.26 3,891,657 6 tab 35.4 -1.26 100,081,219 6 R tab 35.4 -1.17 107,413,026 6 R tab 35.4 -1.26 403,736 6 tab 35.4 -1.26 34,426 6 tab 35.4 -1.26 17,937 6 tab 39.2 3.49 I 6 tab 39.2 3.54 I 6 tab 39.2 3.26 I 6 tab 39.2 3.89 I 6 tab 41.2 -1.57 I 6 tab 41.2 -1.13 I 6 tab 41.2 -1.68 I 6 tab 41.2 -1.30 I 6 tab — — I 6 tab — I 6 tab — — I 6 tab — — I 6 tab —— ————— I 6 tab Q Hz 60 80 100 20 30 30 30 30 60 10 10 10 50 10 50 50 10 30 30 30 60 60 60 60 60 80 80 80 80 100 100 100 100 100 100 100 20 20 20 20 20 20 20 20 0.2 0.2 5 5 5 406 TEST & SAMPLE ID # MAX. STRESS MPa R 5205 AC37 -639 * 5206 9A -501 * 5207 IOA -500 * 5208 13A -502 * 5209 WA7 -613 * 5210 WA8 -588 * 5211 WA9 -596 * 5212 TCl 293 -I 5213 0FTS4 267 -I 5058 TC 15 (45) 264 -I 5059 TC 16 (45) 264 -I 5060 TC 13 (45) 264 -I 5214 TC14 264 -I 5215 TC12 234 -I 5061 TCll (40) 234 -I 5062 TC7 (40) 234 -I 5063 TC9 (40) 234 -I 5064 TC22 205 -I 5065 TC18 (35) 205 -I 5066 TC6 (35) 205 -I 5067 TClO (35) 205 -I 5068 TC21 176 -I 5069 TC19 176 -I 5070 TC20 176 -I 5216 OFTCll 160 -I 5217 OFTC12 187 -I 5218 OFTS19 187 -I 5219 0FTC20 187 -I 5071 TC601 1618 * 5072 TC602 1382 * 5073 TC603 1410 * 5074 TC604 -746 * 5075 TC605 -716 * 5076 TC606 -687 * 5077 TC608 294 -0.5 5078 TC609 294 -0.5 5079 TC613 294 -0.5 5080 TC610 257 -0.5 5081 TC611 257 -0.5 5082 TC616 257 -0.5 5083 TC614 257 -0.5 5084 TC612 220 -0.5 5085 TC615 220 -0.5 E e CYCLES WIDTH GPa % TO FAIL (mm) and Notes - --— I 6 tab — — I 6 tab — I 6 tab — --— I 6 tab — I 6 tab — --— I 6 tab — — I 6 tab — — 3,596 6 tab — — 146,258 6 tab 40.2 0.66 124,950 6 tab 40.2 0.66 337,226 6 tab 40.2 0.66 437,113 6 tab 40.2 0.66 1,260,397 6 tab 40.2 0.58 754,410 6 tab 40.2 0.58 591,914 6 tab 40.2 0.58 781,045 6 tab 40.2 0.58 1,981,821 6 tab 40.2 0.51 2,037,672 6 tab 40.2 0.51 6,141,627 6 tab 40.2 0.51 7,080,727 6 tab 40.2 0.51 7,605,707 6 tab 40.2 0.44 10,382,631 6 tab 40.2 0.44 17,272,745 6 tab 40.2 0.44 100,000,000 6 R tab 40.2 0.40 25,924,921 6 R tab 40.2 0.47 4,850,470 6 tab 40.2 0.47 3,267,903 6 tab 40.2 0.47 6,909,213 6 tab 40.2 4.02 I 6 tab 40.2 3.44 I 6 tab 40.2 3.51 I 6 tab 40.2 -1.86 I 6 tab 40.2 -1.78 I 6 tab 40.2 -1.71 I 6 tab 40.2 0.73 54,401 6 tab 40.2 0.73 151,631 6 tab 40.2 0.73 2,215,625 6 tab 40.2 0.64 338,635 6 tab 40.2 0.64 677,151 6 tab 40.2 0.64 4,237,939 6 tab 40.2 0.64 4,554,382 6 tab 40.2 0.55 3,089,148 6 tab 40.2 0.55 11,113,718 6 R tab Q Hz 5 5 5 5 5 5 5 20 10 30 30 30 30 30 30 30 30 40 40 40 40 50 50 50 60 40 30 30 20 20 20 20 20 20 20 20 20 20 20 20 20 20 20 407 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # MATERIAL (90)4 STRESS MPa Hz GPa % TO FAIL (mm) and Notes Lay-up = (90)4,Vf = 0.38, Average Thickness = 1.38 mm, S.D. = Hexcel DlOO Fabric (340 g/m2), CoRezyn 63-AX-051 Polyester 0.15 mm (min = 1.07 mm, max = 1.75 mm) 5220 90CF7 -111 * 4 9.0 -1.23 I 13 tab 5221 90CF6 -127 * 4 9.0 -1.41 I 13 tab 5222 90CF5 -112 * 4 9.0 -1.24 I 13 tab 5223 90CF4 -128 * 4 9.0 -1.42 I 13 tab 5224 90CF4A -157 * 4 9.0 -1.74 I 13 tab 5225 90CF4B -136 * 4 9.0 -1.51 I 13 tab 5226 90CF8 -HO * 4 9.0 -1.22 I 13 tab 5227 90CF6A -136 * 4 9.0 -1.51 I 13 tab 5086 90CF6T -145 * 4 9.0 -1.61 I 13 tab 5087 90CF5T -160 * 4 9.0 -1.78 I 13 tab 5088 90CF7T -124 * 4 9.0 -1.38 I 13 tab 5228 90CF4A -76 10 40 9.0 -0.84 76,674 13 tab 5089 90CF10T -70 10 50 9.0 -0.79 13,122 13 tab 5090 90CF17T -70 10 50 9.0 -0.79 33,632 13 tab 5091 90CF15T -70 10 50 9.0 -0.79 268,262 13 tab 5092 90CF12T -64 10 70 9.0 -0.72 290,252 13 tab 5093 90CF1 IT -64 10 70 9.0 -0.72 697,512 13 tab 5094 90CF18T -64 10 70 9.0 -0.72 1,330,488 13 tab 5229 90CF19 -59 10 70 9.0 -0.65 1,407,676 13 tab 5230 90CF16 -59 10 70 9.0 -0.65 2,218,971 13 tab 5231 90CF13 -59 10 100 9.0 -0.65 45,789,443 13 tab 5095 90CF21T -59 10 100 9.0 -0.65 12,000,998 13 tab 5096 90CF9T -59 10 100 9.0 -0.65 34,986,168 13 tab 5097 90CF20T -55 10 100 9.0 -0.65 107,839,549 13 R tab 5232 90CF22 -55 10 100 9.0 -0.65 15,368,000 13 R tab 5098 CF501T -113 * 20 9.0 -1.26 I 13 tab 5099 CF502T -113 * 20 9.0 -1.26 I 13 tab 5100 CF503T -121 * 20 9.0 -1.34 I 13 tab 5101 CF504T -115 * 20 9.0 -1.27 I 13 tab 5102 CF518T -88 2 40 9.0 -0.98 121,730 13 tab 5103 CF514T -88 2 40 9.0 -0.98 511,744 13 tab 5104 CF517T -88 2 40 9.0 -0.98 621,878 13 tab 5105 CF513T -82 2 60 9.0 -0.92 853,552 13 tab 5106 CF512T -82 2 60 9.0 -0.92 2,675,404 13 tab 5107 CF507T -82 2 60 9.0 -0.92 3,705,190 13 tab 5108 CF511T -76 2 80 9.0 -0.85 31,971,669 13 tab 5109 CF519T -76 2 80 9.0 -0.85 100,682,804 13 R tab 5233 90CF505 -76 2 70 9.0 -0.79 11,667,961 13 tab 5110 90FT5T 22 * 20 8.6 0.25 I 13 tab 5111 90FT6T 18 * 20 8.6 0.21 I 13 tab 5112 90FT7T 23 * 20 8.6 0.27 I 13 tab 5113 90FT1T 22 * 20 8.6 0.36 I 13 tab 5234 90FT12 18 * I 8.6 0.21 I 13 tab 5114 90FT18TA 14 0.1 60 8.6 0.16 9,383 13 tab 5234 90FT9 14 0.1 30 8.6 0.16 3,257 13 tab 408 TEST & SAMPLE ID # MAX. STRESS MPa R 5235 90FT11 13 0.1 5115 90FT15A 13 0.1 5116 90FT3T 13 0.1 5117 90FT26T 12 0.1 5118 90FT14T 12 0.1 5119 90FT15T 12 0.1 5120 90FT8T 12 0.1 5236 90FT13 12 0.1 5121 90FT4T 11 0.1 5122 90FT11T 11 0.1 5237 90FT19A 14 0.1 5238 90FT13 11 0.1 5239 90FT14A 12 0.1 5240 90FT8 12 0.1 5241 90FT10 10 0.1 5242 90FT13A 13 0.1 5243 90FT14 13 0.1 5244 90FT15 12 0.1 5245 90FT20 12 0.1 5246 90TCA1 19 0.1 5247 90TCBI 21 0.1 5248 90FTC2 24 0.1 5249 90FTC3 24 0.1 5250 90FT18 20 * 5251 90FT19B 19 He 5252 90FT14 23 * 5123 TI501T 21 * 5124 TI502T 21 * 5125 TI503T 23 * 5126 TI509T 15 0.5 5127 TI507T 15 0.5 5128 TI505T 15 0.5 5129 TI508T 14 0.5 5130 TI504T 14 0.5 5131 TI506T 14 0.5 5132 TI514T 10 0.5 5253 TI515T 10 0.5 5133 TI513T 11 0.5 5134 TCHlT 18 * 5135 TCH2T 19 * 5136 TCH3T 17 * 5254 90FT16 21 * 5255 90FT17 19 * 5256 90FTC1 23 * 5137 TCH12T 8 -I 5138 TCH12T 8 -I 5139 TCHlOT 8 -I 5140 TCH14T 7 -I 5141 TCH13T 7 -I E e CYCLES WIDTH GPa % TO FAIL (mm) and Notes 8.6 0.14 2,720,600 13 R tab 8.6 0.15 34,592 13 tab 8.6 0.15 31,952 13 tab 8.6 0.14 3,895,837 13 tab 8.6 0.14 2,372,150 13 tab 8.6 0.14 13,531,172 13 tab 8.6 0.14 2,987,855 13 tab 8.6 0.14 3,810,385 13 tab 8.6 0.13 21,111,725 13 tab 8.6 0.12 102,350,298 13 R tab 8.6 0.16 9,383 13 tab 8.6 0.12 1,813,684 13 tab 8.6 0.14 2,372,150 13 tab 8.6 0.14 987,855 13 tab 8.6 0.11 208,516 13 tab 8.6 0.15 2,759 13 tab 8.6 0.15 385 13 tab 8.6 0.14 1,471 13 tab 8.6 0.14 647 13 tab 8.6 0.21 1,707,026 13 tab 8.6 0.23 49,498 13 tab 8.6 0.27 112,928 13 tab 8.6 0.27 46,842 13 tab 8.6 0.22 I 13 tab 8.6 0.21 I 13 tab 8.6 0.26 I 13 tab 8.7 0.24 I 13 tab 8.7 0.25 I 13 tab 8.7 0.27 I 13 tab 8.7 0.18 53,275 13 tab 8.7 0.18 114,090 13 tab 8.7 0.18 523,634 13 tab 8.7 0.16 1,308,671 13 tab 8.7 0.16 1,665,220 13 tab 8.7 0.16 9,806,694 13 tab 8.7 0.15 31,443,023 13 tab 8.7 0.15 34,693,646 13 tab 8.7 0.15 50,666,199 13 tab 8.8 0.21 I 13 tab 8.8 0.19 I 13 tab 8.8 0.19 I 13 tab 8.8 0.24 I 13 tab 8.8 0.22 I 13 tab 9.27 0.25 I 13 tab 8.8 0.09 45,172 13 tab 8.8 0.09 151,465 13 tab 8.8 0.09 794,513 13 tab 8.8 0.08 47,385 13 tab 8.8 0.08 1,043,369 13 tab Q Hz 40 60 60 80 80 80 100 80 100 100 30 40 40 80 100 70 40 70 60 40 40 80 80 I I I 20 20 20 60 60 60 80 80 80 80 80 80 20 20 20 5 5 5 20 30 30 60 60 4 0 9 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS Hz GPa % TO FAIL (mm) ID # MPa and Notes 5142 TCH16T 7 -I 60 8.8 0.08 3,009,395 13 tab 5143 TCH7T 7 -I 60 8.8 0.08 3,973,407 13 tab 5144 TCH15T 6 -I 80 8.8 0.07 11,733,016 13 tab 5145 TCH19T 6 -I 100 8.8 0.07 100,151,319 13 R tab FIBERGLASS PREPREG (3M - 250E) MATERIALS MATERIAL PP Lay-up = [0],5, Vf = 0.56, Ave. thickness = 1.65 mm, S.D. = 0.03 mm, 3M-SP250E prepreg, Epoxy 4 1 0 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS Hz GPa % TO FAIL (mm) ID # 3480 PPl 12 MPa 1,251 * 13 44.0 2.60 I and Notes 25 3481 PPl 14 1,279 * 13 49.0 2.70 I 25 3482 PPl 15 1,332 * 13 51.6 2.70 I 25 3483 PPl 16 758 0.1 4 52.0 1.52 4,545 25 3484 PPlOl 758 0.1 2 46.5 1.68 7,252 25 3485 PPl 17 758 0.1 2 46.0 1.65 4,825 25 3486 PPlCW 414 0.1 12 47.4 0.84 839,263 25 3487 PPl 18 414 0.1 12 48.7 0.83 491,518 25 3488 PP105 414 0.1 12 42.5 0.92 631,118 25 3489 P P lll 620 0.1 4 43.0 1.40 11,696 25 3490 PPl 13 621 0.1 4 50.5 1.27 13,690 25 3491 PPllO 620 0.1 4 44.3 1.36 26,209 25 3492 PP107 517 0.1 8 45.6 1.09 88,979 25 3493 PPlCW 517 0.1 8 — — 125,521 25 3494 PP103 517 0.1 8 — — 56,119 25 3495 PP102 517 0.1 10 45.9 1.14 124,781 25 tab 3496 PP106 621 0.1 4 47.6 — 17,314 25 3497 PP108 414 0.1 12 — — 269,211 25 3844 PP131 -829 * 13 — ———— I 25 Z 3845 PP126 -842 * 13 —— ———— I 25 Z 3846 PPl 36 -694 * 13 — — I 25 Z MATERIAL PP45 Lay-up = t(±45)2 ]s, Vf= 0.54, Ave. thickness = 1.65 mm, S.D. = 0.04 mm, 3M-SP250E prepreg, Epoxy 3503 PP45201 153 * 13 16.0 I 25 3504 PP45210 153 * 13 18.0 1.55 I 25 3505 PP45209 158 * 13 17.7 — I 25 3506 PP45208 83 0.1 10 18.6 0.55 27,509 25 3507 PP45207 83 0.1 10 20.0 0.52 45,091 25 3508 PP45203 83 0.1 10 18.2 0.56 19,125 25 3509 PP45206 69 0.1 15 18.9 0.40 473,337 25 3510 PP45205 69 0.1 20 15.7 0.51 209,295 25 3511 PP45204 69 0.1 20 18.6 0.43 402,619 25 3512 PP45202 103 0.1 2 17.4 0.86 737 25 3847 PP45212 -160 * 13 — — I 25 MATERIAL PPDD5 Lay-up = [(0)3/±45/(0)3]s ,Vf = 0.56, Ave. thickness = 3.31 mm, S.D. = 0.09 mm, 3M-SP250E prepreg, Epoxy * 3658 3659 PPDD5118 634 PPDD5119 839 13 39.2 13 41.6 I I 15 15 411 TEST & SAMPLE ID # MAX. STRESS MPa R Q Hz E GPa e % CYCLES TO FAIL WIDTH (mm) and Notes 3660 PPDD5120 616 * 13 38.0 ———— I 15 Problems with the previous static tests caused the following gage lengths widths to be heavily reduced. 3662 PPDD5104 1,115 * 13 — — I 6 3663 PPDD5106 1,070 * 13 ———— I 6 3664 PPDD5110 1,080 * 13 — — I 6 3665 PPDD5112 483 0.1 12 — —— — —— 33,888 6 3666 PPDD5109 345 0.1 12 633,893 6 3667 PPDD5114 345 0.1 12 — — —— 408,106 6 3668 PPDD5111 345 0.1 12 — —— — 320,402 6 3669 PPDD5117 414 0.1 10 — — —— 66,207 6 3670 PPDD5116 621 0.1 2 —------- ———— 3,119 6 3671 PPDD5115 621 0.1 2 ———— — —— 4,786 6 3672 PPDD5101 621 0.1 2 — — 2,517 6 3708 PPDD5108 483 0.1 10 — — —— 62,141 6 3709 PPDD5105 483 0.1 5 — -------— 32,975 6 3969 PPDD5200 -716 * 13 ———— — I 25 3970 PPDD5202 -893 * 13 — — —— I 25 3971 PPDD5201 -779 * 13 ———— ———— I 25 GLASS CARBON HYBRIDS MATERIAL DD23 Lay-up = [02/±45/0/0*]s, 0* - AS4-6K Carbon (TPI STYLE 4416), 220 g/m2, Vf = 0.45, Ave. thickness = 3.65 mm, S.D. = 0.11 mm, CoRezyn 63-AX-051 Polyester. 4077 DD23105 649 * 13 27.8 — I 25 tab 4078 DD23106 276 0.1 10 28.9 0.96 1,681,606 25 tab 4079 DD23111 622 * 13 28.1 -------— I 25 tab 4080 DD23107 685 * 13 27.1 -------— I 25 tab 4081 DD23104 414 0.1 2 26.3 1.65 2,803 25 tab 4082 DD23110 634 * 13 27.9 —— I 25 tab 4083 DD23102 414 0.1 2 25.1 1.68 451 25 tab 4084 DD23103 345 0.1 4 28.6 1.17 295,281 25 tab 4085 DD23109 345 0.1 5 25.8 1.14 197,270 25 tab 4086 DD23108 647 * 0.1 26.1 -------— I 25 tab 4087 DD23112 310 0.1 5 28.1 1.12 526,418 25 tab 4088 DD23101 310 0.1 10 26.6 1.08 493,197 25 tab 4101 DD23122 379 0.1 4 27.1 1.47 14,350 25 tab 4102 DD23121 379 0.1 4 28.0 1.37 22,335 25 tab 4103 DD23120 345 0.1 4 28.9 1.17 119,009 25 tab 4104 DD23119 379 0.1 2 27.6 1.42 4,324 25 tab 4214 DD23143 -467 * 13 — — I 25 4215 DD23142 -498 * 13 — — I 25 4216 DD23141 -505 * 13 — — I 25 4217 DD23140 -504 * 13 ———— I 25 4 1 2 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # MATERIAL CG STRESS MPa Hz GPa % TO FAIL (mm) and Notes Lay-up = [O2Zo2cZoZO2cZO2I1Glass = D155, C = AS4-6K Carbon (TPI STYLE 4416), 220gZm2, Vf = 0.56, Ave. thickness = 2.66 mm, S.D. = 0.06 mm, CoRezyn 63-AX-051 Polyester 4089 CGllO 934 * 13 72.5 I 25 tab 4090 CG106 861 * 13 65.5 ———— I 25 tab 4091 CG104 414 0.1 12 65.8 0.59 1,368,362 25 tab 4092 CG109 552 0.1 8 63.7 0.79 141,368 25 tab 4093 CGlOl 552 0.1 9 68.3 0.89 55,233 25 tab 4094 CGl 12 483 0.1 10 61.4 0.73 253,069 25 tab 4095 CG108 552 0.1 5 64.4 0.81 109,701 25 tab 4096 CG105 414 0.1 12 71.4 0.56 1,900,285 25 tab 4097 CG107 690 0.1 2 62.4 1.02 1,969 25 tab 4098 CGll l 690 0.1 2 64.8 0.94 13,577 25 tab 4099 CGl 13 690 0.1 2 62.0 1.04 10,770 25 tab 4100 CG103 965 * 13 63.5 63.5 I 25 tab MATERIAL CA Lay-up = (O)12, AS4-6K Carbon (TPI STYLE 4416), 220g/m2, Vf = 0.48, Ave. thickness = 2.82 mm, S.D. = 0.24 mm, CoRezyn 63-AX-051 Polyester 4105 CAl 13 1504 * 13 112 1.34 I 18 tab 4106 CA 109 1666 * 13 112 1.49 I 18 tab 4107 CAll l 1364 * 13 118 1.15 I 18 tab 4108 CAllO 1207 0.1 I 154 0.90 9 18 tab 4109 CAl 12 1034 0.1 5 112 0.82 28,497 18 tab 4110 CA 108 862 0.1 12 112 0.70 1,030,350 18 tab 4111 CA 106 862 0.1 12 118 0.68 77,101 ISRtab 4112 CA 107 862 0.1 10 113 0.70 2,364,140 18 tab D 155 STRAND TESTS 413 GLASS ROVING TESTS Owens Coming Fabrics roving number E-450-PVE, Catalog Number OC107B-AC-450, OCl 11 A-AB-450,2000 fibers (average fiber diameter = 15.98 pm, standard deviation = 1.53 pm, maximum = 19.4 pm, minimum = 12.5 pm, sample size = 14,000) The following six D155 fabric rolls were obtained over the time period of 1993 to 1999. TEST & M AX . R Q E e CYCLES W IDTH SAM PLE Load H z GPa % TO FA IL (mm) ID # N and N otes D 1 5 5 R o l l I 3 739 D 155TA 1 1054 * 13 I tow 3740 D 15 5T A 2 1061 * 13 — —— I tow 3741 D 155T A 3 993 * 13 — —— I tow 3742 D 15 5T A 4 94 0 * 13 — —— I tow 3743 D 155T A 5 1015 * 13 — - — I tow 3744 D 1 5 5T A 6 967 * 13 — —— I tow 3745 D 155T A 7 973 * 13 — —— I tow 3746 D 155T A 8 1014 * 13 ——— — I tow 3747 D 15 5T A 9 98 7 * 13 — —— I tow 3748 D 1 5 5T A 10 1054 * 13 ——— —— I tow 3749 D 155TA 11 1019 * 13 ——— — I tow 3750 D 1 5 5T A 12 1084 * 13 — — I tow 3751 D 155T A 13 9 7 0 * 13 — —— I tow 3752 D 1 5 5T A 14 1084 * 13 —— I tow 3753 D 155T A 15 975 * 13 — — —— I tow 3754 D 1 5 5T A 16 1064 * 13 — —— I tow 3755 D 155T A 17 9 82 * 13 — —— I tow 3756 D 1 5 5T A 18 9 99 * 13 — — I tow 3757 D 155T A 19 1015 * 13 — —— I tow 3758 D 1 5 5T A 20 981 * 13 — —— I tow 3759 D 155TA 21 1012 * 13 —— I tow 3760 D 1 5 5T A 22 1040 * 13 — — I tow 3761 D 155T A 23 1081 * 13 — —— I tow 3762 D 155T A 24 1036 * 13 — — I tow 3763 D 155T A 25 1010 * 13 — — I tow 3764 D 1 5 5T A 26 9 1 2 * 13 — - —— I tow 3765 D 1 5 5T A 27 9 2 2 * 13 — I tow 3766 D 1 5 5T A 28 1051 * 13 — - — I tow 3767 D 1 5 5T A 29 991 * 13 — — — I tow 3768 D 1 5 5T A 30 995 * 13 — — I tow D155 Roll 2 3769 D 155TB 1 1401 * 13 I tow 3770 D 1 55T B 2 1310 * 13 ——— —— I tow TEST & M AX . R SAM PLE Load ID # N 3771 D 155T B 3 1431 * 3 772 D 1 55T B 4 1403 * 3773 D 155T B 5 1380 * 3 774 D 1 55T B 6 1347 * 3775 D 155T B 7 1398 * 3 776 D 155T B 8 1361 * 3 777 D 155T B 9 1386 * 3 778 D 1 55T B 10 1362 * 3 779 D 155TB 11 1339 * 3 780 D 1 55T B 12 1413 * 3781 D 155T B 13 1352 * 3 7 8 2 D 1 55T B 14 1366 * 3783 D 155T B 15 1459 * 3 784 D 1 55T B 16 1412 * 3785 D 155T B 17 1279 * 3 786 D 155T B 18 1381 * 3787 D 155T B 19 1416 * 3788 D I 5 5T B 20 1420 * 3789 D 155TB 21 1322 * 3 7 9 0 D 155TB 22 1263 * 3791 D 155T B 23 1353 * 3 7 9 2 D I 5 5T B 24 1446 * 3793 D 155T B 25 1411 * 3794 D 1 55T B 26 1310 * 3795 D 155T B 27 1378 * 3 796 D 155T B 28 1372 * 3 797 D 155T B 29 1349 * 3 798 D 1 55T B 30 1319 * D 15 5 R o l l 3 3 7 99 D 155TC 1 1419 * 3 8 0 0 D 155TC 2 1256 * 3801 D 155TC 3 1356 * 3 802 D 155TC 4 1375 * 3803 D 155TC 5 1322 * 3 804 D 155TC 6 1410 * 3805 D 155TC 7 1407 * 3 806 D 155TC 8 1392 * 3807 D 155TC 9 1467 * 3808 D 155TC 10 1456 * 3809 D 1 5 5T C 1 I 1444 * 3 810 D 155TC 12 1367 * 3811 D 155TC 13 1399 * 3 812 D 155TC 14 1336 * 3813 D 155TC 15 1429 * 3 814 D 155TC 16 1326 * 3815 D 155TC 17 1404 * E e C YCLES W IDTH GPa % TO FA IL (mm) and N o tes — — I tow I tow I tow — — I tow — — I tow I tow I tow — — I tow — — I tow — — I tow — — I tow — — I tow I tow I tow — — I tow I tow — — I tow I tow — — I tow — — I tow — — I tow — — I tow — — I tow I tow — — I tow — — I tow — — I tow — — I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow Q Hz 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 TEST & M AX . R SAM PLE Load ID # N 3816 D 155TC 18 1353 * 3817 D 155TC 19 1456 * 3818 D 155T C 20 1336 * 3819 D 155TC 21 1366 * 3 8 2 0 D 155TC 22 1379 * 3821 D 155TC 23 1325 * 3 822 D 155TC 24 1250 * 3823 D 155TC 25 1358 * 3824 D 155TC 26 1401 * 3825 D 155TC 27 1345 * 3 826 D 155TC 28 1387 * 3827 D 155TC 29 1428 * 3828 D 155TC 30 1350 * D155 Roll 4 4 4 7 4 D 155TD 1 1117 * 4 4 7 5 D 15 5T D 2 1096 * 4 4 7 6 D 155TD 3 1123 * 4 4 7 7 D 155T D 4 1089 * 4 4 7 8 D 155TD 5 1078 * 4 4 7 9 D 15 5T D 6 1077 * 4 4 8 0 D 155T D 7 1075 * 4481 D 155T D 8 1119 * 4 4 8 2 D 155T D 9 1108 * 4 483 D 1 5 5T D 10 1170 * 4 4 8 4 D 1 5 5 T D 1 1 534 0.1 4 485 D 1 5 5T D 12 534 0.1 4 4 8 6 D 155T D 13 534 0.1 4 4 8 7 D 155T D 14 534 0.1 4 4 8 8 D 155T D 15 534 0.1 4 4 8 9 D 1 5 5T D 16 667 0.1 4 4 9 0 D 155T D 17 667 0.1 4491 D 155T D 18 667 0.1 4 4 9 2 D 155T D 19 667 0.1 4 493 D 1 5 5T D 20 667 0.1 4 4 9 4 D 155TD 21 667 0.1 4 495 D 155T D 22 445 0.1 4 4 9 6 D 155T D 23 44 5 0.1 4 4 9 7 D 155T D 24 445 0.1 4 4 9 8 D 155T D 25 44 5 0.1 4 4 9 9 D 1 5 5T D 26 445 0.1 4 5 0 0 D 155T D 27 35 6 0.1 4501 D 155T D 28 35 6 0.1 4 5 0 2 D 155T D 29 35 6 0.1 4 503 D 1 5 5T D 30 35 6 0.1 4 5 0 4 D 155TD 31 35 6 0.1 4 505 D 155T D 32 311 0.1 I tow I tow I tow I tow I tow — — I tow — — I tow I tow I tow I tow I tow — — I tow I tow E e CYCLES WIDTH GPa % TO FAIL (mm) and Notes I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow 6 0 3 ,8 5 4 tow 9 0 0 ,2 3 4 tow 4 7 0 ,1 0 3 tow 1 ,503 ,261 tow 8 5 2 ,8 5 3 tow 101 ,8 6 7 tow 15 ,4 5 6 tow 10 ,2 1 8 tow 10 ,4 2 6 tow 2 0 ,8 8 3 tow 5 9 ,6 8 8 tow 4 ,0 0 2 ,6 9 4 tow 6 ,1 6 8 ,9 4 2 tow 2 ,7 2 7 ,3 9 5 tow 5 ,7 4 8 ,8 6 0 tow 3 ,6 3 4 ,7 5 2 tow 4 1 ,9 8 1 ,3 4 1 tow 2 3 ,5 4 8 ,0 3 0 tow 6 7 ,7 4 8 ,3 9 4 tow 7 1 ,2 4 7 ,8 3 9 tow 1 2 ,2 4 5 ,9 1 7 tow 169 ,4 8 4 ,1 5 1 tow Q H z 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 10 10 10 10 10 5 5 5 5 5 5 20 20 20 20 20 50 50 50 50 50 80 TEST & MAX. R SAMPLE Load ID # N 4506 D155TD33 311 0.1 4507 D155TD34 311 0.1 4508 D155TD35 311 0.1 4509 D155TD36 311 0.1 4563 D155TD37 778 0.1 4564 D155TD38 778 0.1 4565 D155TD39 778 0.1 4567 D155TD40 778 0.1 4568 D155TD41 778 0.1 D155 Roll 4B 4640 D155TD42 1212 * 4641 D155TD43 1287 * 4642 D155TD44 1278 Sk 4643 D155TD45 1187 Sk 4644 D155TD46 1187 Sk 4645 D155TD47 1195 Sk 4646 D155TD48 1212 sk 4647 D155TD49 1212 sk 4648 D155TD50 1187 sk 4649 D155TD51 1295 sk 4650 D155TD52 1183 sk 4651 D155TD53 1195 sk 4652 D155TD54 1241 sk 4653 D155TD55 1095 sk 4654 D155TD56 1183 sk 4655 D155TD57 1145 sk 4656 D155TD58 1187 sk 4657 D155TD59 1053 sk 4658 D155TD60 1087 sk 4659 D155TD61 1303 sk 4660 D155TD62 1204 * 4661 D155TD63 1212 * 4662 D155TD64 1145 sk 4663 D155TD65 1062 sk 4664 D155TD66 1157 sk 4665 D155TD67 1287 * 4666 D155TD68 1250 sk 4667 D155TD69 1129 sk 4668 D155TD70 1274 sk 4669 D155TD71 1254 sk D155 Roll 5 4510 D155TE551 1220 sk 4511 D155TE546 1208 sk 4512 D155TE515 1205 sk — — 2 5 4 ,2 2 6 ,0 8 5 tow ......................... 3 8 2 ,0 9 5 ,4 3 0 tow — — 1 8 0 ,7 6 0 ,5 6 0 tow — — 6 7 1 ,7 3 4 ,5 4 0 tow 5 2 6 tow 375 tow — -- 16 0 tow 43 3 tow — 5 44 tow E e CYCLES WIDTH GPa % TO FAIL (mm) and Notes I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow Q Hz 80 80 80 80 2 2 2 2 2 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 TEST & M AX . R SAM PLE Load ID # 4513 D155TE527 N 1182 * 4514 D155TE547 1193 * 4515 D155TE516 1161 * 4516 D155TE564 1181 * 4517 D155TE555 1143 * 4518 D155TE572 1157 * 4519 D155TE548 1122 * 4520 D155TE549 1246 * 4521 D155TE566 1203 * 4522 D155TE556 1276 * 4523 D155TE559 1205 * 4524 D155TE517 1164 * 4525 D155TE534 1233 * 4526 D155TE538 1124 * 4527 D155TE532 1162 * 4528 D155TE520 1142 * 4529 D155TE550 1171 * 4530 D155TE557 1193 * 4531 D155TE563 1264 * 4532 D155TE539 1090 * 4533 D155TE567 1128 * 4534 D155TE554 1139 * 4535 D155TE569 1146 * 4536 D155TE558 1195 * 4537 D155TE576 1249 * 4538 D155TE570 1151 * 4539 D155TE571 1201 * 4540 D155TE553 778 0.1 4541 D155TE552 778 0.1 4542 D155TE518 778 0.1 4543 D155TE561 778 0.1 4544 D155TE562 778 0.1 4546 D155TE509 667 0.1 4547 D155TE505 667 0.1 4548 D155TE512 667 0.1 4549 D155TE511 667 0.1 4550 D155TE510 667 0.1 4551 D155TE531 534 0.1 4552 D155TE542 534 0.1 4553 D155TE541 534 0.1 4554 D155TE525 534 0.1 4555 D155TE533 534 0.1 4556 D155TE514 534 0.1 4557 D155TE591 445 0.1 4558 D155TE592 445 0.1 4559 D155TE596 445 0.1 4560 D155TE593 445 0.1 4561 D155TE597 445 0.1 4562 D155TE598 445 0.1 417 E e CYCLES W IDTH GPa % TO FA IL (mm) and N otes I tow — — I tow — — I tow — — I tow — — I tow — — I tow — - I tow — — I tow — — I tow — — I tow — - I tow — - I tow — — I tow — — I tow — — I tow — — I tow — — I tow — — I tow — — I tow — — I tow — — I tow — — I tow — — I tow — - I tow — — I tow — - I tow — — I tow — — 11 ,640 tow — — 2,983 tow — - 4 ,5 9 6 tow — — 3 ,6 7 8 tow — - 4 ,8 1 7 tow — — 30 ,9 5 3 tow — — 10 ,943 tow — — 19 ,520 tow — - 10 ,173 tow — - 14 ,350 tow — — 8 5 8 ,8 1 0 tow — — 159 ,9 4 4 tow — - 2 5 4 ,2 4 0 tow — - 3 8 6 ,3 8 0 tow — - 2 3 5 ,3 6 4 tow — — 5 2 5 ,6 2 3 tow — — 3 ,2 1 8 ,5 0 4 tow - — — 3 ,9 2 4 ,3 6 3 tow — - 2 ,3 1 9 ,7 9 2 tow — - 6 ,7 5 9 ,2 4 4 tow — - 2 ,5 3 5 ,1 9 8 tow — - 4 ,4 6 8 ,1 7 0 tow Q Hz 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 5 5 5 5 5 5 5 5 5 5 10 10 10 10 10 10 20 20 20 20 20 20 418 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE Load H z GPa % TO FA IL (mm) ID # N and N o tes D 1 5 5 R o l l 5 B 4 6 7 0 D 155TE 99 1412 * 13 I tow 4671 D 1 55T E 100 1408 * 13 — — I tow 46 7 2 D 155TE 101 1462 * 13 — - — I tow 4673 D 155T E 102 1362 * 13 — — I tow 46 7 4 D 155TE 103 1391 * 13 — —— I tow 4675 D 155T E 104 1454 * 13 — — I tow 46 7 6 D 155TE 105 1462 * 13 — —— I tow 4 6 7 7 D 155T E 106 1420 * 13 — —— I tow 4 6 7 8 D 155T E 107 1437 * 13 — — I tow 4 6 7 9 D 155T E 108 1375 * 13 — — I tow 46 8 0 D 155T E 109 1475 * 13 — — I tow 4681 D 1 5 5T E 1 10 1350 * 13 — — I tow 4 6 8 2 D 155TE 111 1337 * 13 — —— I tow 4683 D 1 5 5T E 1 12 1370 * 13 — — I tow 4 6 8 4 D 1 5 5T E 1 13 1375 * 13 — —— I tow 4685 D 155T E 114 1445 * 13 — — I tow 4 6 8 6 D 155T E 115 1342 * 13 — — I tow 4687 D 155T E 116 1356 * 13 — — I tow 4 6 8 8 D 155T E 117 1387 * 13 — —— I tow 4689 D 1 5 5T E 1 18 1475 * 13 — — I tow 46 9 0 D 1 5 5T E 1 19 1429 * 13 — — I tow 4691 D 155T E 120 1417 * 13 — — —— I tow 46 9 2 D 155TE 121 1387 * 13 — —— I tow 4693 D 155T E 122 1371 * 13 — —— I tow 46 9 4 D 155TE 123 1446 * 13 — — —— I tow 4695 D 155T E 124 1404 * 13 — —— I tow 4 6 9 6 D 155TE 125 1362 * 13 — — I tow 46 9 7 D 155T E 126 1342 * 13 — — I tow 46 9 8 D 155T E 127 1471 * 13 ——— — I tow 46 9 9 D 155T E 128 1396 * 13 — — I tow D155 Roll 6 4 7 0 0 D 155TF1 1195 * 13 I tow 4701 D 155T F 2 1262 * 13 — —— I tow 4 7 0 2 D 155TF 3 1171 * 13 — — I tow 4 7 0 2 D 155T F 4 1171 * 13 — — I tow 4703 D 155T F 5 1321 * 13 — — —— I tow 4 7 0 4 D 155T F 6 1237 * 13 — - — I tow 4705 D 155T F 7 1171 * 13 — — I tow 47 0 6 D 155T F 8 1204 * 13 —— - - I tow 4707 D 155T F 9 1208 * 13 — I tow 47 0 8 D 155T F 10 1154 * 13 — — I tow 47 0 9 D 1 5 5T F 1 I 1287 * 13 - — — I tow 4 7 1 0 D 155T F 12 1188 * 13 —— — I tow 4711 D 155T F 13 1197 * 13 ——— —— I tow TEST & M AX . R SAM PLE Load ID # N 4 7 1 2 D 155T F 14 1171 * 4 713 D 155T F 15 1229 * 4 7 1 4 D 155T F 16 1208 * 4 7 1 5 D 155T F 17 1213 * 4 7 1 6 D 155T F 18 1229 * 4 7 1 7 D 155T F 19 1146 * 4 7 1 8 D 155T F 20 1204 * 4 7 1 9 D 155TF21 1262 * 4 7 2 0 D 155T F 22 1183 * 4721 D 155T F 23 1487 * 4 7 2 2 D 155T F 24 1296 * 4 7 2 3 D 155T F 25 1137 * 4 7 2 4 D 155T F 26 1204 * 4 7 2 5 D 155T F 27 1271 * 4 7 2 6 D 155T F 28 1314 * 4 7 2 7 D 155T F 29 1246 * 4 7 2 8 D 155T F 30 1246 * D155 Roll 6B 4729 D155TF31 1404 * 4730 D155TF32 1262 * 4731 D155TF33 1221 * 4732 D155TF34 1350 * 4733 D155TF35 1179 * 4734 D155TF36 1146 * 4735 D155TF37 1338 * 4736 D155TF38 1221 * 4737 D155TF39 1262 * 4738 D155TF40 1362 * 4739 D155TF41 1254 * 4740 D155TF42 1396 * 4741 D155TF43 1313 * 4742 D155TF44 1346 * 4743 D155TF45 1387 * 4744 D155TF46 1279 * 4745 D155TF47 1287 * 4746 D155TF48 1362 * 4747 D155TF49 1096 * 4748 D155TF50 1296 * 4749 D155TF51 1246 * 4750 D155TF52 1304 * 4751 D155TF53 1287 * 4752 D155TF54 1304 * 4753 D155TF55 1237 * 4754 D155TF56 1267 * 4755 D155TF57 1304 * 4756 D155TF58 1338 * E e C YCLES W IDTH GPa % TO FA IL (mm ) and N o tes — — I tow — — I tow I tow — — I tow — — I tow — — I tow — — I tow — — I tow — I tow — I tow I tow — — I tow — — I tow — — I tow I tow — — I tow — — I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow Q Hz 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 TEST & M AX . R SAM PLE Load ID # N 475 7 D 155T F 59 1304 * 4 7 5 8 D 155T F 60 1262 * D 1 5 5 Roll 6 C 4 8 0 0 D 155TF 61 1393 * 4801 D 155T F 62 1260 * 4 8 0 2 D 155T F 63 1268 * 4803 D 155T F 64 1410 * 4 8 0 4 D 155T F 65 1385 * 4 805 D 155T F 66 1443 * 4 8 0 6 D 155T F 67 1402 * 4 8 0 7 D 155T F 68 1260 * 4 808 D 155T F 69 1318 * 4 8 0 9 D 155T F 70 1310 * 4 8 1 0 D 155TF 71 1314 * 4811 D 155T F 72 1331 * 4 8 1 2 D 155T F 73 1277 * 4 813 D 155T F 74 1302 * 4 8 1 4 D 155T F 75 1393 * 4 815 D 155T F 76 1064 * 4 8 1 6 D 155T F 77 1210 * 4 8 1 7 D 155T F 78 1293 * 4818 D 155T F 79 1314 * 4819 D 155T F 80 1310 * 4 8 2 0 D 155TF 81 1427 * 4821 D 155T F 82 1306 * 4 8 2 2 D 155T F 83 1277 * 4 823 D 155T F 84 1343 * 4 8 2 4 D 155T F 85 1368 * 4 825 D 155T F 86 1268 * 4 8 2 6 D 155T F 87 1335 * 4 8 2 7 D 155T F 88 1331 * 4 8 2 8 D 155T F 89 1352 * 4 8 2 9 D 155T F 90 1310 * D155 Roll 6D 4 8 3 0 D 155TF91 1168 * 4831 D 155T F 92 1368 * 4 8 3 2 D 155T F 93 1389 * 4 833 D 155T F 94 1298 * 4 8 3 4 D 155T F 95 1285 * 4 835 D 155T F 96 1364 * 4 8 3 6 D 155T F 97 1318 * 4 837 D 155T F 98 1310 * 4 838 D 155T F 99 1326 * 4 839 D 1 55T F 100 1343 * — — I tow — I tow 420 E e CYCLES WIDTH GPa % TO FAIL (mm) and Notes I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow I I tow I tow I tow I tow I tow I tow I tow I tow I tow I tow Q H z 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 13 421 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE ID # Load N H z GPa % TO FA IL (mm) and N o tes 4 8 4 0 D 155T F 101 1310 * 13 I tow 4841 D 1 5 5T F 1 0 2 1410 * 13 — —— I tow 4 8 4 2 D 155T F 103 1343 * 13 ——— —— I tow 4 8 4 2 D 1 5 5T F 1 0 4 1335 * 13 — —— I tow 4843 D 155T F 105 1210 * 13 — —— I tow 4844 D 1 5 5T F 1 0 6 1160 * 13 — — I tow 4845 D 1 55T F 107 1385 * 13 ——— — I tow 4 8 4 6 D 1 55T F 108 1110 * 13 — —— I tow 4847 D 1 55T F 109 1352 * 13 — —— I tow 4 8 4 8 D 1 5 5T F 1 1 0 1298 * 13 ——— —— I tow 4849 D 1 5 5T F 1 11 1343 * 13 — —— I tow 4 8 5 0 D 1 5 5T F 1 12 1352 * 13 — — I tow 4851 D 1 5 5T F 1 13 1318 * 13 I tow 4 85 2 D 1 5 5T F 1 14 1352 * 13 —— —— I tow 4853 D 1 5 5T F 1 15 1335 * 13 — —— I tow 4 8 5 4 D 1 5 5T F 1 1 6 1356 * 13 — — I tow 4855 D 1 55T F 117 1285 * 13 ——— —— I tow 4 8 5 6 D 1 5 5T F 1 18 1293 * 13 — — I tow 4857 D 1 5 5T F 1 19 1243 * 13 ——— — I tow 4858 D B 1 2 0 D 1 5 5T F 1 2 0 1335 * 13 I tow Owens Coming Fabrics Roving number E-1200-PVE, catalog number OC-380-JC-451 (1200). (750 fibers) DB 120 Roll 5 4 5 6 9 D B 120T A 1 37 0 * 13 — — I tow 457 0 D B 12 0T A 2 317 * 13 — —— I tow 4571 D B 120T A 3 37 4 * 13 — — I tow 457 2 D B 12 0T A 4 389 * 13 — — I tow 4573 D B 120T A 5 396 * 13 — — I tow 45 7 4 D B 12 0T A 6 377 * 13 — — I tow 4575 D B 12 0T A 7 28 4 * 13 — — I tow 4 5 7 6 D B 12 0T A 8 329 * 13 — — I tow 45 7 7 D B 12 0T A 9 31 0 * 13 ——— — I tow 4578 D B 1 2 0T A 1 0 37 0 * 13 — — I tow 457 9 D B 120T A 11 378 * 13 — — I tow 4 5 8 0 D B 1 2 0T A 1 2 314 * 13 — — I tow 4581 D B 12 0T A 13 304 * 13 — —— I tow 4 5 8 2 D B 1 2 0T A 1 4 373 * 13 — —— I tow 4583 D B 12 0T A 15 348 * 13 — —— I tow 45 8 4 D B 1 2 0T A 1 6 375 * 13 — - — I tow 4585 D B 12 0T A 17 344 * 13 — — I tow 4 5 8 6 D B 12 0T A 18 305 * 13 — — I tow 45 8 7 D B 12 0T A 19 371 * 13 — — I tow 4588 D B 12 0T A 20 393 * 13 — — I tow 422 TEST & SAM PLE ID # M AX . Load N R Q Hz E GPa e % CYCLES TO FA IL W IDTH (mm) and N otes 4 5 8 9 D B 120TA 21 351 * 13 . . . I tow 4 5 9 0 D B 12 0T A 22 3 50 * 13 ——— —— I tow 4591 D B 120T A 23 332 * 13 — —— I tow 4 5 9 2 D B 12 0T A 24 293 * 13 — —— I tow 4593 D B 120T A 25 387 * 13 — —— I tow 4 5 9 4 D B 12 0T A 26 347 * 13 — — —— I tow 45 9 5 D B 12 0T A 27 358 * 13 ——— — I tow 4 5 9 6 D B 12 0T A 28 36 4 * 13 — —— I tow 45 9 7 D B 12 0T A 29 307 * 13 — —— I tow 45 9 8 D B 12 0T A 30 32 0 * 13 — —— I tow 45 9 9 D B 120T A 31 403 * 13 — —— I tow 4 6 0 0 D B 120T A 32 377 * 13 — — I tow 4601 D B 120T A 33 346 * 13 — —— I tow 4 6 0 2 D B 12 0T A 34 35 2 * 13 — —— I tow 4603 D B 120T A 35 377 * 13 — —— I tow 4 6 0 4 D B 12 0T A 36 317 * 13 — — I tow 4605 D B 12 0T A 37 37 6 * 13 ——— — I tow 4 6 0 6 D B 120T A 38 36 6 * 13 — —— I tow 4 6 0 7 D B 120T A 39 319 * 13 — —— I tow 4 6 0 8 D B 12 0T A 40 330 * 13 — —— I tow 4609 D B 120TA 41 351 * 13 — — —— I tow 4 6 1 0 D B 12 0T A 42 358 * 13 ——— —— I tow 4611 D B 120T A 43 376 * 13 — —— I tow 4 6 1 2 D B 12 0T A 44 339 * 13 —— —— I tow 423 Owens Coming 990-BC-2385-4093, 208 fiber strand (A verage fiber d iam eter = 10.71 jam, standard dev ia tion = 0 .9 4 pm , m axim um = 13 .9 6 pm , m in im um = 8 .33 pm , sam ple s iz e = 1 ,820). The average area used for stress ca lcu lations w as 0 .0 0 4 0 5 4 mm2. A 45 fiber strand, impregnated w ith C oR ezyn 6 3 -A X -051 , w as manufactured from this strand. The gage length o f these coupons were 25 ±5 mm . A sp ecia l speaker con e based testin g apparatus w as u sed for th ese tests, see R eference 10. TE ST & M AX . R Q E e CYCLES W IDTH SAM PLE Load H z GPa % TO FA IL (mm) ID # grams and N o te s 4 9 0 0 STR 63 1266 * 120 I tow 4901 STR 60 1506 * 120 ———— ———— I tow 4 9 0 2 STR 54 1383 * 120 ——— ———— I tow 4903 STR 52 1181 * 120 — —— — I tow 4 9 0 4 STR 40 1376 * 120 ———— ———— I tow 4905 STR 44 1687 * 120 ———— ———— I tow 4 9 0 6 STR 33 1281 * 120 ———— ———— I tow 4907 STR 17 1367 * 120 ———— ———— I tow 4 9 0 8 STR 14 1189 * 120 ———— ———— I tow 4 9 0 9 STR 12 1126 * 120 — —— —— — I tow 4 9 1 0 STR lO 1214 * 120 ———— ———— I tow 4911 ST R 152 1349 * 120 ———— —— — I tow 4 9 1 2 STR141 1344 * 120 ———— ———— I tow 4913 STR 133 1300 * 120 ———— —— — I tow 4 9 1 4 S T R 122 1285 * 120 -------— ———— I tow 4915 STR71 1192 * 120 ———— — — I tow 4 9 1 6 S T R 10 2 1261 * 120 ———— — —— I tow 4 9 1 7 S T R l l 300 0.1 2 0 0 — ———— 1 ,1 0 0 ,0 0 0 ,0 0 0 tow R 4 9 1 8 STR 16 500 0.1 80 — — 3 ,1 5 1 ,6 3 7 tow 4 91 9 STR 13 500 0.1 80 — — 5 2 1 ,4 1 6 tow 4 9 2 0 STR 19 500 0.1 80 — — 1 ,8 8 7 ,5 1 2 tow 4921 STR61 500 0.1 80 — — 1 0 ,5 9 0 ,5 4 6 tow 4 9 2 2 STR 34 500 0.1 80 — — 6 6 0 ,7 6 2 tow 4923 STR 43 500 0.1 80 — — 2 ,9 7 0 ,6 1 3 tow 4 9 2 4 STR51 500 0 .1 80 — — 6 ,2 7 1 ,8 5 3 tow 4925 STR 32 500 0.1 80 — — 1 ,1 6 3 ,0 4 4 tow 4 9 2 6 STR 64 5 00 0.1 80 — 2 ,3 7 1 ,5 3 2 tow 4 92 7 STR 42 500 0.1 80 — — 2 3 ,1 9 8 ,2 0 5 tow 4 92 8 STR 50 50 0 0.1 80 — — 877 ,701 tow 4 92 9 STR31 500 0.1 80 — — — 1 ,8 6 7 ,1 8 5 tow 4 9 3 0 STR 53 4 0 0 0.1 100 — — 2 1 ,2 5 6 ,3 3 5 tow 4931 STR41 4 0 0 0.1 100 — — 5 4 1 ,1 6 8 ,0 6 9 tow 4 9 3 2 S T R 154 7 00 0.1 5 0 — — 2 8 ,0 2 6 tow 4933 STR 150 7 00 0.1 50 — — —— 117 ,1 3 5 tow 4 9 3 4 STR 153 7 00 0.1 50 — — —— 8 7 ,9 5 6 tow 4935 S T R 143 7 00 0.1 50 — — — 8 2 0 ,1 0 8 tow 4 9 3 6 STR121 7 00 0.1 50 — — — 3 7 ,2 0 8 tow 4 9 3 7 S T R 130 7 00 0.1 50 — 119 ,1 3 7 tow 4938 STR151 7 0 0 0.1 5 0 — — — 8 3 4 ,7 3 8 tow 4 93 9 STR 72 7 0 0 0.1 5 0 — — — 4 4 6 ,6 7 9 tow 4 9 4 0 S T R 120 7 00 0.1 5 0 — — 174 ,0 7 2 tow 424 4941 STR132 700 0.1 4942 STR144 700 0.1 4943 STR123 700 0.1 4944 STR140 600 0.1 4945 STR84 600 0.1 4946 STR83 600 0.1 4947 STR131 600 0.1 4948 STR94 600 0.1 4949 STR30 400 0.1 4950 STR134 450 0.1 4951 STR142 1396 * 4952 STR90 1284 * 4953 STR70 1335 * — — 204 ,8 7 1 tow — — 154 ,7 0 6 tow — — 14 ,218 tow — — 2 ,3 1 3 ,6 7 8 tow — — 4 ,1 3 8 ,7 9 1 tow — — 3 ,1 8 5 ,3 1 1 tow — — 2 ,5 6 4 ,9 7 1 tow — — 19 ,2 4 8 ,9 0 8 tow — — 1 ,0 0 0 ,0 0 0 ,0 0 0 tow R — --- 1 ,0 0 0 ,0 0 0 ,0 0 0 tow R — — I tow — --------- I tow — — — I tow 50 50 50 100 100 100 100 100 120 150 120 120 120 RESIDUAL STRENGTH (C overing T ests 5 1 5 0 - 5 2 3 4 ) 425 MATERIAL DD16A Lay-up = [9 0 /0 /± 4 5 /0 ]s, V f = 0 .4 2 , A ve . th ickness = 3 .95 mm , S .D . = 0 .0 8 mm , C oR ezyn 63 -AX -051 Polyester TEST & M AX . R Q E e CYCLES W IDTH SAM PLE STRESS H z GPa % TO FA IL (mm) ID # M Pa and N otes T ests 5 1 5 0 - 5 1 8 8 w ere b a se lin e static strength and fa tigue tests 5 1 5 0 R 59 661 * 13 ———— — I 8 5151 R 27 658 * 13 ———— —— — I 8 5 152 R 26 6 57 * 13 ———— ———— I 8 5153 R 16 701 * 13 — ———— I 8 5 154 R 102 685 * 13 ———— I 8 5155 R61 6 8 6 * 13 ———— ———— I 8 5 156 R 120 6 58 * 13 —— —— ———— I 8 5 157 R121 678 * 13 ———— ———— I 8 5158 R 122 683 * 13 ———— ———— I 8 5159 R l 23 691 * 13 ———— —— — I 8 5 160 R 124 625 * 13 ———— ——— I 8 5161 R 125 675 * 13 ———— ———— I 8 5162 R 42 684 * 13 ———— ———— I 8 5163 R 74 673 * 13 ———— ———— I 8 5164 R 56 705 * 13 ——— ———— I 8 5165 R71 67 4 * 13 — — ———— I 8 5 166 R l lO 66 4 * 13 ———— ———— I 8 5167 R l l l 6 65 * 13 ———— ———— I 8 5168 R21 665 * 13 — — I 8 5169 R H 6 8 0 * 13 — —— ———— I 8 5 1 7 0 R 35 20 7 0.1 10 — — 1 9 2 ,7 8 0 8 5171 R 58 207 0.1 10 — — 6 3 6 ,7 4 2 S R 5172 R 22 207 0.1 10 — — 1 ,6 9 4 ,8 7 9 8 5173 R 57 207 0.1 10 ———— —— — 9 6 1 ,2 1 4 8 5 174 R 44 27 6 0.1 6 ———— — 3 8 ,1 5 2 8 5175 R23 241 0.1 8 — — 104 ,645 8 5 176 R 13 241 0.1 8 — — 2 5 6 ,9 2 3 8 5177 R 46 241 0.1 8 — — 169 ,1 0 8 8 5178 R7 241 0.1 8 — — 2 3 6 ,6 1 7 8 5179 R 48 241 0.1 8 — — 176 ,4 7 9 8 5 1 8 0 R 50 241 0.1 8 — -------— 149 ,7 7 8 8 5181 R43 241 0.1 8 — — 3 2 5 ,4 3 9 8 5 1 8 2 R41 241 0.1 8 — — 7 8 ,4 4 5 8 5183 R 64 241 0.1 8 — ———— 5 2 ,3 2 0 8 5 184 R 68 241 0.1 8 -------— 67 8 5 7 8 5185 R 77 241 0.1 8 — — 116 ,518 8 5 186 R 52 241 0.1 8 --------- — 157 ,118 8 5187 R 78 241 0.1 8 — — 3 8 2 ,6 5 3 8 5188 R 62 241 0.1 8 — — 105 ,7 3 8 8 426 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE STRESS H z GPa % TO FA IL (mm ) ID # M Pa and N o te s T est cou p on s w ere se le c ted for three testing sequences: 5 0 ,0 0 0 , 1 00 ,0 0 0 and 2 0 0 ,0 0 0 c y c le s at a m ax im um stress o f 241 M Pa (R = 0 .1 ) , after w h ich the test coupon w as sta tica lly tested for residual strength. T est coupons w h ich fa iled prior to the com pletion o f the d esigna ted number o f c y c le s are listed , but shou ld not be used in the b a se lin e fa tigue behavior due to sam ple b iasing . T ests 5 1 8 9 - 5 2 0 5 , 1 0 0 ,0 0 0 c y c le s T ests 5 1 8 9 - 5 1 9 3 fa iled prior to com p letion o f the 1 0 0 ,0 0 0 c y c le sequence 5189 R3 241 0.1 8 — — 9 4 ,7 1 8 8 X 5190 R 65 241 0.1 8 — — 8 8 ,0 8 2 8 X 5191 R 60 241 0.1 8 — —— — 8 3 ,9 6 2 8 X 5192 R8 241 0.1 8 — — 82 ,7 6 8 8 X 5193 R 38 241 0.1 8 — — 6 6 ,7 5 7 8 X T ests 5 1 9 4 - 5 2 0 5 w ere cy c led for 1 00 ,0 00 cy c le s at 2 4 1 /2 4 M Pa and then tested for residual strength 5194 R5 241 0.1 8 — — 100 ,0 0 0 8 R5 60 2 * 13 — — —— I 8 RS 5195 R 34 241 0.1 8 ———— —— — 100 ,0 0 0 8 R 34 543 * 13 ———— ———— I 8 RS 51 9 6 R lO l 241 0.1 8 — — 100 ,0 0 0 8 R lO l 583 * 13 — — I 8 RS 5197 R 63 241 0.1 8 —— — ———— 100 ,0 0 0 8 R 63 4 23 * 13 — I 8 RS 5198 R 29 241 0.1 8 — 100 ,0 0 0 8 R 29 48 2 * 13 — — — I 8 RS 5199 R 19 241 0.1 8 — — 100 ,0 0 0 8 R 19 623 * 13 — -------— I 8 RS 5200 R6 241 0.1 8 — ——— 1 0 0 ,0 0 0 8 R6 563 * 13 —— — ———— I 8 RS 5201 R 24 241 0.1 8 — — —— 100 ,0 0 0 8 R 24 314 * 13 — — —— I 8 RS 5202 R 39 241 0.1 8 — — 100 ,0 0 0 8 R 39 571 * 13 — ———— I 8 RS 5203 R 72 241 0.1 8 -------- — 100 ,0 0 0 8 R 72 45 4 * 13 — — I 8 RS 5204 R 45 241 0.1 8 — — 100 ,0 0 0 8 R 45 4 8 0 * 13 — — I 8 RS 5205 R 54 241 0.1 8 — — 1 0 0 ,0 0 0 8 R 54 2 7 0 T ests 5 2 0 6 - 5 2 1 7 , 5 0 ,0 0 0 cy c le s * 13 — — I 8 RS 5206 R 12 241 0.1 8 — — 50 ,0 0 0 8 R 12 485 * 13 — I 8 RS 5207 R lO 241 0.1 8 — — 5 0 ,0 0 0 8 R lO 554 * 13 — — I 8 RS 5208 R 20 241 0.1 8 — — 50 ,0 0 0 8 R 20 628 * 13 — — I 8 RS 5209 R31 241 0.1 8 — — 50 ,0 0 0 8 R31 583 * 13 — ———— I 8 RS 5210 R 67 241 0.1 8 — — 5 0 ,0 0 0 8 R 67 4 27 * 13 ———— — I 8 RS 427 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE ID # STRESS M Pa H z GPa % TO FA IL (mm) and N o tes 5211 R53 241 0.1 8 5 0 ,0 0 0 8 R 53 54 0 * 13 ———— ——— I 8 RS 5212 R 28 241 0.1 8 — ——— 50 ,0 0 0 8 R 28 568 * 13 ———— ——— I 8 RS 5213 R 32 241 0.1 8 — —— 50 ,0 0 0 8 R 32 583 * 13 — ——— I 8 RS 5214 R 37 241 0.1 8 — ———— 50 ,0 0 0 8 R 37 58 2 * 13 ---— ———— I 8 RS 5215 R 66 241 0.1 8 — — 50 ,0 0 0 8 R 66 56 6 * 13 — — I 8 RS 5216 R 117 241 0.1 8 ——— — 50 ,0 0 0 8 R 117 529 * 13 — ———— I 8 RS 5217 R 79 241 0.1 8 — — 50 ,0 0 0 8 R 79 5 6 8 * 13 ............................ T ests 5 2 1 8 - 5 2 3 4 , 2 0 0 ,0 0 0 cy c le s T ests 5 2 1 8 - 5 2 2 8 fa iled prior to com p letion o f the 2 0 0 ,0 0 0 c y c le sequence I 8 RS 5218 R 17 241 0.1 8 — — 162 ,465 8 X 5219 R 47 241 0.1 8 ---— 4 7 ,1 8 2 8 X 5220 R25 241 0.1 8 — ——— 177 ,6 4 0 8 X 5221 R55 241 0.1 8 — — 93 ,3 0 0 8 X 5222 R9 241 0.1 8 —— — 84 ,7 03 8 X 5223 R 36 241 0.1 8 — —— 168 ,0 6 9 8 X 5224 R15 241 0.1 8 — — 93 ,8 7 7 8 X 5225 R75 241 0.1 8 — —— 113 ,1 1 4 8 X 5226 R 40 241 0.1 8 — — 60 ,5 9 2 8 X 5227 R 70 241 0.1 8 —— —— 103 ,240 8 X 5228 R 18 241 0.1 8 ———— — 133 ,677 8 X T ests 5 2 2 9 - 5 2 3 4 w ere c y c led for 2 0 0 ,0 0 0 c y c le s at 2 4 1 /2 4 M Pa and then tes ted for residual strength 5229 R51 241 0.1 8 — — 20 0 ,0 0 0 8 R51 249 * 13 ———— ———— I 8 RS 5230 R 4 241 0.1 8 — — 200 ,0 0 0 8 R 4 4 6 4 * 13 ———— I 8 RS 5231 R73 241 0.1 8 ———— — 200 ,0 0 0 8 R73 269 * 13 — ——— I 8 RS 5232 R 14 241 0.1 8 — — 200 ,0 0 0 8 R 14 541 * 13 ——— — I 8 RS 5233 R 33 241 0.1 8 ———— —— 200 ,0 0 0 8 R 33 298 * 13 ———— — I 8 RS 5234 R 69 241 0.1 8 ——— — 20 0 ,0 0 0 8 R 69 337 * 13 ———— — I 8 RS 428 Static Strength, Residual Strength after 50,000, 100,000 and 200,000 Cycles at 241 MPa, and Fatigue Failure at a Maximum Stress of 241 MPa, R = 0.1 (Tension Fatigue), [90/0/±45/0)s Laminate 800 700 600 500 CL 5 vf I 0) v> 400 C0) g 300 •i 200 100 ▲ r i i 5-N F a tigue Static S treng th Vfter 5 0 ,0 0 0 cy c le s Vfter 1 00 ,0 00 cy c le s vfter 2 0 0 ,0 0 0 cy c le s ailed P rio r to 100 ,0 00 cyc les A V o iI ■ / ) I ■ C ] a / _______I l Z l ! ▼ ^ L 3 r x F 1 C - - - - - - - - - - - - - - - - - - - - - - - - C 3 ] _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ I r + F ailed P no i to 200 ,00 0 cyc les 1 C I C i C ] I r =f H - A d A A - h i L A i - A A - 1 I X I 0 100000 200000 Cycles 300000 400000 429 Environmental testing of different matrix materials in [0/±45/0]s, [90/±45/90]s, and [±45]3 laminates. Tests 5 235 through 5 7 14 invo lved static tests o f f iv e d ifferen t matrix m aterials at d ifferen t temperatures (25 , 40 , 55 and 70 °C ) and d ifferent moisture contents. For com posite moisture gain , the test coupon s w ere p laced in a d is tilled w ater bath at a temperature o f 5 0 °C for 1 ,2 00 hours (4 33 hours for the Iso -P o lyester). The temperature that the coupon s w ere tested at is listed in the last data co lum n. TEST & M AX . R Q E e CYCLES W IDTH SAM PLE ID # STRESS M Pa H z GPa % TO FA IL (mm) and N o tes Lay-up = [0 /± 45 /0 ]s, V f = 0 .3 6 , A ve . th ickness = 3 .1 6 mm , S .D . = 0 .11 mm , C oR ezyn 6 3 -A X -0 5 1 P o lyester 5235 p-t-1 4 7 8 * 0.1 2 3 .7 — I 25 °C 5 2 3 6 p -t-2 4 8 9 * 0.1 2 3 .4 — I 25 °C 5237 p-t-3 495 * 0.1 2 2 .9 ——— I 25 °C 5238 p -t -15 47 7 * 0.1 2 1 .9 — I 4 0 °C 5239 p-t-5 517 * 0.1 2 2 .7 — I 40 °C 5 2 4 0 p -t-6 4 9 6 * 0.1 23 .5 — I 4 0 °C 5241 p -t-7 4 6 0 * 0.1 2 2 .0 — I 55 0C 5 24 2 p-t-8 4 8 2 * 0.1 23 .5 — I 55 °C 5243 p-t-9 4 9 7 * 0.1 23 .9 —— I 55 °C 5244 p -t -10 4 2 2 * 0.1 19 .9 — I 70 °C 5245 p -t -11 4 3 2 * 0.1 2 2 .2 — I 70 °C 5246 p -t -12 403 * 0.1 20 .5 ---— I 70 0C T ests 5 2 4 7 - 5 2 5 8 had an average m oisture ga in o f 0 .92% (cond ition ed 1 ,2 00 hours in 5 0 °C water (DI)) 5 247 w -p -t- l 4 3 4 * 0.1 20 .3 — I 25 °C 5248 w -p -t-2 441 * 0.1 2 1 .2 —-- I 25 °C 5249 w -p -t-3 4 5 5 * 0.1 2 3 .0 — I 25 °C 52 5 0 w -p -t-4 444 * 0.1 2 0 .6 — I 4 0 °C 5251 w -p -t-5 4 4 2 * 0.1 2 2 .7 — I 4 0 °C 5252 w -p -t-6 411 * 0.1 2 0 .2 — I 4 0 °C 5253 w -p -t-7 4 0 9 * 0.1 2 2 .2 — I 55 °C 5254 w -p -t-8 387 * 0.1 22 .5 — I 55 0C 5255 w -p -t-9 401 * 0.1 2 0 .8 — I 55 °C 52 5 6 w -p -t-10 39 0 * 0.1 2 1 .4 — I 70 °C 5257 w -p -t- l I 3 9 2 * 0.1 2 1 .3 — I 70 0C 5258 w -p -t - l 2 383 * 0 .1 21 .1 — I 70 °C 5259 p-c-1 -6 0 4 * 13 — — I 25 °C 5260 p -c -2 -6 3 4 * 13 — — I 25 °C 5261 p -c-3 -641 * 13 — — I 25 0C 5262 p -c -4 -5 2 2 * 13 — —— I 4 0 0C 5263 p -c-5 -591 * 13 — \ I 4 0 °C 5264 p -c -6 -5 8 0 * 13 --- - --- - I 4 0 0C 5265 p -c-7 -455 * 13 — — I 55 °C 52 6 6 p -c -8 -4 8 0 * 13 —— — I 55 0C 5267 p -c-9 -4 3 7 * 13 — — I 55 °C 5268 p -c -1 0 -3 4 8 * 13 — — I 70 °C 5269 p -c -1 I -3 8 8 * 13 — —— I 70 0C 527 0 p -c -1 2 -405 * 13 — — I 70 °C T ests 5271 - 5 2 8 2 had an average m oisture gain o f 0 .87% (cond ition ed 1 ,2 00 hours in 5 0 '3C water (D I)) 5271 w -p -c-1 -3 2 7 * 13 — — I 25 0C 5272 w -p -c -2 -341 * 13 — — I 25 °C 430 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE ID # STRESS M Pa Hz GPa % TO FA IL (mm) and N o tes 5273 w -p -c -3 -3 3 4 * 13 I 25 0C 5274 w -p -c -4 -3 0 6 * 13 — — I 4 0 °C 5275 w -p -c -5 -307 * 13 — — I 40 °C 52 7 6 w -p -c -6 -3 1 7 * 13 — — I 40 0C 5277 w -p -c -1 0 -2 6 6 * 13 — ---— I 55 0C 5278 w -p -c -1 1 -2 7 7 * 13 — — I 55 0C 5279 w -p -c -1 2 -268 * 13 — — I 55 °C 5 2 8 0 w -p -c -7 -2 4 0 * 13 — — I 70 °C 5281 w -p -c -8 -2 4 3 * 13 — — I 70 0C 5282 w -p -c -9 -2 4 3 * 13 —--- — I 70 °C Lay-up = [9 0 /± 45 /9 0 ]s, V f = 0 .3 6 , A ve . th ickness = 3 .15 mm , S .D . = 0 .1 0 mm , C oR ezyn 63 -AX -051 Polyester 5283 p-tt-1 7 8 .7 * 0.1 8 .9 ———— I 25 0C 5284 p -tt-2 7 5 .0 * 0.1 9 .6 — I 25 °C 5285 p-tt-3 68 .5 * 0.1 9 .3 I 25 0C 5715 1T01 6 8 .2 * 0.1 10 .7 2 .2 6 I 25 0C 5716 1T02 7 5 .2 * 0.1 10 .5 3 .1 4 I 25 0C 5717 1T03 7 7 .8 * 0.1 10.1 3.51 I 25 °C 5286 p-tt-4 8 6 .0 * 0.1 8 .3 ---— I 4 0 °C 5287 p-tt-5 84 .7 * 0.1 8 .8 ———— I 40 °C 5288 p -tt-6 85.1 * 0.1 8 .3 — I 4 0 °C 5289 p -tt-7 84.1 * 0.1 6.1 ---— I 55 °C 5 2 9 0 p -tt-8 84 .0 * 0.1 6 .0 ---— I 55 °C 5291 p -tt-9 81.1 * 0.1 6 .3 — I 55 °C 5292 p -tt-10 70 .8 * 0.1 4 .7 — I 70 °C 5293 p -tt-11 72 .3 * 0.1 5 .3 I 70 °C 5294 p -tt-12 7 0 .6 * 0.1 3 .8 ---— I 70 0C Tests 5 2 9 5 - 5 3 0 6 had an average m oisture gain o f 0 .92% (cond ition ed 1,2 0 0 hours in 5 0 '3C water (D I)) 5295 w -p-tt-1 5 6 .4 * 0.1 7 .3 — I 25 °C 5296 w -p -tt-2 55 .8 * 0.1 7.1 — I 25 0C 5297 w -p -tt-3 56 .3 * 0.1 7 .0 — I 25 0C 5839 lt0 4 7 7 .2 * 0.1 8 .9 4 2 .95 I 25 °C 5840 lt0 5 71 .9 * 0.1 8 .6 8 2 .7 8 I 25 0C 5841 lt0 6 75 .8 * 0.1 9 .0 2 2 .7 9 I 25 °C 5298 w -p -tt-4 5 9 .2 * 0.1 6.1 — I 40 °C 5299 w -p-tt-5 58 .5 * 0.1 6 .2 — I 40 °C 53 0 0 w -p -tt-6 5 9 .2 * 0 .1 5 .8 — I 4 0 °C 5301 w -p -tt-7 53 .1 * 0.1 5 .4 — I 55 °C 5302 w -p -tt-8 5 4 .2 * 0.1 5 .4 — I 55 0C 5303 w -p -tt-9 53 .8 * 0.1 5 .4 — I 55 0C 5 30 4 w -p -tt-10 4 7 .2 * 0.1 3 .8 — I 70 0C 5305 w -p -tt -1 1 4 8 .5 * 0.1 3 .7 I 70 °C 5 3 0 6 w -p -tt-12 50 .9 * 0.1 3 .4 — I 70 °C Lay-up = [± 4 5 ]3, V f = 0 .3 6 , A v e . th ickness = 3 .1 2 mm , S .D . = 0 .0 8 mm , C oR ezyn 6 3 -A X -051 P o lyester 5307 p -4 5 t - l 111 * 0.1 10 .2 — I 25 0C 5308 p -45 t-2 115 * 0.1 11.3 —-- I US 5 3 09 p -45 t-3 111 * 0.1 11 .3 — I 25 0C 5 31 0 p -45 t-4 108 * 0.1 8 .9 — I 40 °C 5311 p -45 t-5 105 * 0.1 10.1 — I 40 0C 5312 p -45 t-6 108 * 0.1 9 .2 —— I 40 0C 431 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE ID # STRESS M Pa Hz GPa % TO FA IL (mm) and N o tes 5313 p -45 t-7 91 .5 * 0.1 7 .6 I 55 °C 5314 p -45 t-8 9 0 .3 * 0.1 7 .7 — I 55 °C 5315 p -45 t-9 88 .9 * 0.1 7 .3 ---— I 55 0C 5316 p -4 5 t-1 0 7 2 .8 * 0.1 5.1 ——— I 70 0C 5317 p -4 5 t - l l 7 2 .4 * 0.1 4 .9 ---— I 70 °C 5318 p -4 5 t-1 2 7 2 .9 * 0.1 5 .4 ---- I 7 0 °C T ests 5 3 1 9 - 5 3 3 0 had an average m oisture gain o f 0 .86% (cond ition ed 1 ,2 00 hours in 5 0 '3C water (D I)) 5 319 w -p -4 5 t- l 6 5 .8 * 0.1 7 .6 —— I 25 0C 5320 w -p -45 t-2 6 9 .4 * 0.1 7 .7 — I 25 °C 5321 w -p -45 t-3 6 6 .6 * 0.1 7 .5 — I 25 0C 5322 w -p -45 t-4 68 .5 * 0.1 6.1 — I 4 0 °C 5323 w -p -45 t-5 6 9 .2 * 0.1 7.1 — I 4 0 °C 5324 w -p -45 t-6 6 4 .6 * 0.1 6 .2 — I 4 0 °C 5325 w -p -45 t-7 5 8 .7 * 0.1 5 .4 — I 55 0C 5326 w -p -45 t-8 5 9 .6 * 0.1 5.1 ——— I 55 °C 5327 w -p -45 t-9 6 1 .2 * 0.1 5 .5 — I 55 °C 5328 w -p -4 5 t-1 0 4 3 .5 * 0.1 3 .0 ——- I 7 0 °C 5329 w -p -4 5 t - l l 45 .1 * 0.1 3 .3 — I 70 °C 5330 w -p -45 t-12 4 6 .2 * 0.1 3 .0 — I 70 °C Lay-up = [0 /± 4 5 /0 ]s, V f = 0 .3 6 , A ve . th ickness = 3 .1 6 mm , S .D . = 0 .11 mm , D erakane 4 1 1C -50 , v iny l ester 5331 4 1 1 - t - l 5 99 * 0.1 2 7 .0 — I 25 0C 5332 411-1 -2 525 * 0.1 2 5 .6 ———— I 25 °C 5333 411-1-3 621 * 0.1 2 5 .9 ———— I 25 °C 5334 411-1-4 5 46 * 0.1 2 4 .6 ——— I 4 0 0C 5335 411 -t-5 518 * 0.1 2 5 .4 —— I 40 0C 5336 411 -t-6 595 * 0.1 2 5 .2 ———— I 40 °C 5337 411 -t-7 5 46 * 0.1 2 5 .6 ———— I 55 °C 5338 41 l- t -8 5 5 8 * 0.1 2 5 .4 ——— I 55 0C 5339 411 -t-9 5 62 * 0.1 24 .5 ———— I 55 °C 53 4 0 4 1 1 -t -1 0 46 3 * 0.1 3 0 .0 ——— I 70 °C 5341 4 1 1 - t - l I 5 3 8 * 0.1 2 7 .9 ———— I 70 °C 5342 41 l - t -1 2 5 0 2 * 0.1 2 3 .2 I 7 0 0C T ests 5 3 4 3 - 5 3 5 4 had an average m oisture ga in o f 0 .34% (cond ition ed 1 ,2 00 hours in 5 0 13C water (D I)) 5 343 w -4 1 1 -t - l 4 45 * 0.1 24 .3 — I 25 0C 5344 w -411 -t-2 441 * 0.1 2 5 .9 I 25 0C 5345 w -41 l- t -3 4 1 7 * 0.1 23 .3 --------- I 25 °C 5346 w -41 l - t -4 4 1 3 * 0.1 2 5 .9 — I 4 0 0C 5347 w -41 l- t -5 4 3 4 * 0.1 2 5 .0 —— — I 4 0 °C 5348 w -411 -t-6 4 0 9 * 0.1 26 .3 — I 4 0 0C 5349 w -411 -t-7 4 0 5 * 0.1 2 5 .9 — —— I 55 0C 53 5 0 w -41 l - t -8 384 * 0.1 25 .1 I 55 °C 5351 w -411 -t-9 383 * 0.1 2 3 .9 — —— I 55 °C 5352 w -4 1 1 -t-1 0 378 * 0.1 25 .5 I 7 0 0C 5353 w -4 1 1 - t - l l 381 * 0.1 2 6 .4 — I 7 0 0C 5354 w -41 l - t -1 2 3 8 0 * 0.1 24 .1 — I 7 0 0C 5355 4 1 1 -c - l -555 * 13 — — I 25 °C 53 5 6 411-C -2 -5 0 9 * 13 — — — —— I 25 °C 5357 411-C -3 -5 9 4 * 13 -------— — I 25 °C 5358 411-C -4 -505 * 13 ———— —— — I 4 0 0C 432 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE ID # STRESS M Pa H z GPa % TO FA IL (mm) and N otes 5 3 59 411-C -5 -513 * 13 I 4 0 0C 53 6 0 411-C -6 -5 0 4 * 13 ———— ———— I 4 0 °C 5361 411-C -7 -438 * 13 ———— ——— I 55 0C 536 2 411-C -8 -447 * 13 ——— ———— I 55 °C 5363 411-C -9 -4 9 2 * 13 ———— ——— I 55 °C 5364 41 l - c -1 0 -445 * 13 —— ——— I 70 °C 5365 4 1 1 - c - l l -4 53 * 13 ———— ——— I 70 °C 5 3 6 6 41 l - c -1 2 -447 * 13 ———— —— I 70 °C T ests 5 3 6 7 - 5 3 7 8 had an average m oisture ga in o f 0 .32% (cond ition ed 1 ,200 hours in 5 0 '3C water (D I)) 5 3 67 w -4 1 1-c-1 -5 1 9 * 13 ———— ———— I 25 0C 5368 w -4 1 1 -c -2 -5 3 6 * 13 ———— ———— I 25 0C 5369 w -4 1 1 -c -3 -5 0 8 * 13 ——— ———— I 25 °C 5370 w -4 1 1-c-4 -5 2 2 * 13 -——— ———— I 40 0C 5371 w -4 1 1 -c -5 -5 1 4 * 13 ———— ———— I 40 °C 5 3 7 2 w -41 l - c -6 -505 * 13 ———— ———— I 40 °C 5373 w -41 l- c -1 0 -5 1 6 * 13 ———— ———— I 55 °C 5 3 7 4 w - 4 1 1 - c - l l -4 7 7 * 13 ——— —— I 55 °C 5375 w -41 l- c -1 2 -4 8 6 * 13 ———— ———— I 55 °C 5 3 7 6 W-411-C-7 -455 * 13 ———— ———— I 70 °C 5 3 7 7 w -41 l- c -8 -475 * 13 ———— ——— I 70 °C 5378 w -41 l - c -9 -4 9 4 * 13 ———— ——— I 70 °C Lay-up = [9 0 /± 4 5 /9 0 ]s, V f = 0 .3 6 , A v e . th ickness = 3 .1 5 mm , S .D . = 0 .1 0 mm , D erakane 4 1 1C -50 5379 4 1 1 -t t - l 5 6 .9 * 0.1 11.1 — I 25 0C 5 38 0 41 l- t t -2 5 6 .2 * 0.1 11 .7 ———— I 25 °C 5381 41 l- tt-3 54 .8 * 0.1 12 .4 ———— I 25 0C 5382 41 l- t t -4 61 .5 * 0.1 10 .9 ———— I 4 0 0C 5383 41 l- tt-5 62 .3 * 0.1 10.3 ———— I 40 0C 5384 41 l- t t -6 63 .3 * 0.1 10.8 ———— I 40 °C 5385 411 -tt-7 6 3 .2 * 0.1 6 .9 - - - - I 55 °C 5 3 8 6 41 l- t t -8 61 .5 * 0.1 7.1 ———— I 55 0C 5387 411 -tt-9 61 .5 * 0.1 7 .3 ——— I 55 °C 5388 41 l- t t -1 0 6 0 .4 * 0.1 6 .6 —— I 70 0C 5389 4 1 1 - t t - l I 5 2 .6 * 0.1 6 .0 ———— I 70 °C 5 3 9 0 411 -U -12 5 6 .4 * 0.1 6 .4 ———— I 70 0C 5718 ts 4 1 11 5 7 .6 * 0.1 9 .3 4 .3 9 I 25 0C 5719 ts 4 1 12 5 4 .8 * 0.1 9 .2 4 .9 2 I 25 0C 57 2 0 ts 4 1 13 5 6 .6 * 0.1 9 .5 4.01 I 25 °C T ests 5391 - 5 4 0 2 had an average m oisture ga in o f 0 .34% (cond ition ed 1 ,200 hours in 5 0 °C water (D I)) 5391 w -4 1 1 -tt - l 51 .1 * 0.1 8 .6 — I 25 °C 5 3 9 2 w -41 l- t t -2 51 .4 * 0.1 8 .2 ——— I 25 °C 5393 w -41 l- tt-3 5 0 .9 * 0.1 8 .5 —--- I U 5 3 9 4 w -41 l- t t -4 56 * 0.1 8 .5 ——— I 40 °C 5395 w -41 l- tt-5 55 .5 * 0.1 8 .2 ———— I 40 °C 5 3 9 6 w -41 l- t t -6 50 .9 * 0.1 8 .4 ——— I 4 0 °C 5397 w -411 -tt-7 4 8 .4 * 0.1 8.1 — I 55 °C 5398 w -41 l- tt-8 52 .1 * 0.1 7 .9 — —— I 55 °C 5 3 9 9 w -411 -tt-9 52 .1 * 0.1 8 .2 I 55 0C 5400 w -41 l- t t -1 0 5 2 .6 * 0.1 7 .3 — —— I 70 0C 5401 w -4 1 1 -tt - l I 52 * 0.1 7 .5 — — I 70 °C 433 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE ID # STRESS M Pa H z GPa % TO FA IL (mm) and N o tes 5 4 0 2 w -41 l- t t -1 2 50 .1 * 0.1 7 .2 I 7 0 °C Lay-up = [± 4 5 ]3, V f = 0 .3 6 , A ve . th ickness = 3 .1 2 mm , S .D . = 0 .0 8 mm , D erakane 4 H C -5 0 v inyl ester 5403 41 l - 4 5 t - l 140 * 0.1 11 .0 ———— I 25 0C 5404 41 l -4 5 t -2 133 * 0.1 10.8 ——— I 25 °C 5405 411 -4 5 t-3 130 * 0.1 10 .9 ———— I 25 °C 54 0 6 41 l- 4 5 t-4 121 * 0.1 10.5 —— — I 4 0 0C 5407 41 l-4 5 t-5 121 * 0.1 10 .6 ———— I 4 0 0C 5408 4 1 1 -4 5 t-6 123 * 0.1 9 .8 ———— I 4 0 °C 5409 41 l- 4 5 t-7 112 * 0.1 9 .8 ——— I 55 °C 54 1 0 41 l-4 5 t-8 116 * 0.1 9 .6 ———— I 55 °C 5411 4 1 1 -4 5 t-9 117 * 0.1 10 ———— I 55 0C 54 1 2 411 -451 -10 103 * 0.1 9 .7 ———— I 7 0 °C 5413 411-451-11 100 * 0.1 8 .5 ———— I 7 0 °C 5414 411 -451 -12 100 * 0.1 8 .9 ———— I 7 0 °C T ests 5 4 1 5 - 5 4 2 6 had an average m oisture gain o f 0 .24% (cond ition ed 1 ,200 hours in 5 0 °C water (D I)) 5 415 w -4 1 1 -4 5 t - l 135 * 0.1 11 .4 ———— I 25 0C 5416 w -4 1 1 -4 5 t-2 135 * 0.1 11 .4 ———— I 25 °C 5417 w -41 l-4 5 t-3 133 * 0.1 10 .2 ———— I 25 °C 5418 w -41 l-4 5 t-4 129 * 0.1 ———— ———— I 4 0 °C 5419 w -41 l-4 5 t-5 125 * 0.1 9 .7 ———— I 4 0 °C 54 2 0 w -41 1 -4 5 t-6 127 * 0.1 9 .5 —— — I 4 0 °C 5421 w -41 l-4 5 t-7 HO * 0.1 9 .0 ———— I 55 °C 54 2 2 w -4 11 -4 5 t-8 119 * 0.1 9 .2 ———— I 55 °C 5423 w -4 11 -4 5 t-9 121 * 0.1 10.3 ———— I 55 0C 5424 w -41 l- 4 5 t-1 0 HO * 0.1 9 .2 ———— I 7 0 °C 5425 w -4 1 1 -4 5 t- l I 112 * 0.1 9 .2 —— — I 7 0 °C 54 2 6 w -4 1 1 -4 5 t-1 2 112 * 0.1 9 .3 ———— I 7 0 °C Lay-up = [0 /± 4 5 /0 ]s, V f = 0 .3 6 , A ve . th ickness = 3 .1 6 mm , S .D . = 0 .11 mm , SC -14 E poxy 5 427 s c l4 - t - l 6 9 6 * 0.1 2 6 .6 ———— I 25 °C 5428 s c l4 - t - 2 727 * 0.1 2 8 .0 ———— I 25 0C 5429 s c l4 - t - 3 648 * 0.1 2 4 .6 ———— I 25 °C 5 4 3 0 s c l4 - t - 4 561 * 0.1 25 .1 —— — I 4 0 °C 5431 s c l4 - t - 5 603 * 0.1 25 .3 —— — I 4 0 °C 5 4 3 2 s c l4 - t - 6 5 72 * 0.1 25 .8 ———— I 4 0 °C 5433 s c l4 - t - 7 584 * 0.1 2 4 .2 -------- I 55 0C 5434 s c l4 - t - 8 548 * 0.1 2 7 .0 ———— I 55 0C 5435 sc 14-1-9 578 * 0.1 23 .5 ———— I 55 0C 54 3 6 s c l4 - t - 1 0 5 7 0 * 0.1 23 .5 ———— I 7 0 0C 5437 s c l4 - t - l I 5 69 * 0.1 2 3 .4 — I 7 0 °C 5438 s c l4 - t - 1 2 595 * 0.1 24 .8 — I 7 0 °C T ests 5 4 3 9 - 5 4 5 0 had an average m oisture gain o f 1.34% (cond ition ed 1 ,200 hours in 5 0 0C water (D I)) 5 4 39 w - s c l4 - t - l 5 69 * 0.1 2 5 .0 — I 25 0C 5 4 4 0 w -s c l4 - t -2 4 3 7 * 0 .1 2 3 .9 ———— I 25 0C 5441 w -s c l4 - t -3 4 5 4 * 0.1 24 .3 ——— I 25 °C 5 4 4 2 w -s c l4 - t -4 4 2 6 * 0.1 2 3 .6 ———— I 4 0 0C 5443 w -s c l4 - t -5 428 * 0.1 2 5 .4 ——— I 4 0 °C 5444 w -s c l4 - t -6 4 3 4 * 0.1 23 .3 — I 4 0 °C 5445 w -s c l4 - t -7 396 * 0.1 23 .5 — I 55 0C 54 4 6 w -s c l4 - t -8 4 0 4 * 0.1 25 .5 ———— I 55 °C 434 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE ID # STRESS M Pa Hz GPa % TO FA IL (mm) and N o tes 5447 w -sc 14-t-9 4 0 8 * 0.1 2 3 .8 ----- I 55 0C 5448 w -s c l4 - t -1 0 362 * 0.1 22 .1 ----- I 7 0 °C 5449 w - s c l4 - t - l I 351 * 0.1 21 .8 ----- I 7 0 °C 5450 w -sc 14-1-12 357 * 0.1 23 .1 ----- I 7 0 °C 5451 s c l 4 - c - l -563 * 13 ——— ----- I 25 °C 5452 s c I 4 -c -2 -508 * 13 —— ----- I 25 °C 5453 s c l4 - c - 3 -5 3 2 * 13 — ----- I 25 °C 5454 s c l4 - c - 4 -511 * 13 ———— ----- I 4 0 °C 5455 s c l4 - c - 5 -555 * 13 —— ----- I 4 0 °C 5456 s c l4 - c - 6 -5 3 7 * 13 ———— ----- I 4 0 0C 5457 s c l4 - c - 7 -4 9 2 * 13 — ----- I 55 °C 5458 s c l4 - c - 8 -4 6 4 * 13 — ----- I 55 °C 5459 s c l4 - c - 9 -4 8 0 * 13 — ----- I 55 °C 5 4 6 0 s c l4 - c - 1 0 -4 1 4 * 13 ———— ----- I 7 0 °C 5461 s c l 4 - c - l I -4 0 6 * 13 ——— ----- I 7 0 0C 5462 s c l4 - c - 1 2 -4 2 4 * 13 ———— ----- I 7 0 °C T ests 5 4 6 3 - 5 4 7 4 had an average m oisture gain o f 1.41% (cond ition ed 1 ,200 hours in 5 0 '3C water (D I)) 5463 w - s c l 4 - c - l -4 5 4 * 13 — ----- I 25 0C 5464 w -s c l4 - c -2 -4 5 6 * 13 ——— ----- I 25 °C 5465 w -s c l4 -c -3 -4 6 2 * 13 ———— ----- I 25 0C 5466 w -s c l4 - c -4 -428 * 13 ——— ----- I 4 0 0C 5467 w -s c l4 -c -5 -3 3 4 * 13 ———— ----- I 4 0 0C 5468 w -s c l4 - c -6 -4 1 2 * 13 ——— ----- I 4 0 0C 5469 w -s c l4 - c -1 0 -3 1 8 * 13 ———— ----- I 55 °C 5470 w - s c l4 - c - l I -371 * 13 ———— ----- I 55 °C 5471 w -s c l4 - c -1 2 -3 6 8 * 13 ———— ----- I 55 °C 5472 w -s c l4 -c -7 -375 * 13 — I 70 °C 5473 w -s c l4 - c -8 -293 * 13 ——— ----- I 7 0 °C 5474 w -s c l4 - c -9 -3 4 9 * 13 ———— ----- I 7 0 °C Lay-up = [9 0 /± 4 5 /9 0 ]s, V F = 0 .3 6 , A ve . th ickness = 3 .1 5 mm , S .D . = 0 .1 0 mm , SC -1 4 E poxy 5475 s c l4 - t t -1 4 8 6 .6 * 0.1 9.1 ----- I 25 °C 5476 sc l4 - t t -2 9 2 .4 * 0.1 9 .5 ----- I 25 °C 5477 sc l4 - t t -3 91 .8 * 0.1 8 .8 ----- I 25 °C 5478 sc l4 - t t -4 97 * 0.1 8 .7 ----- I 4 0 0C 5479 sc l4 - t t -5 89 .7 * 0.1 8 .4 ----- I 4 0 °C 5480 sc l4 - t t -6 92 .1 * 0.1 8 .2 ----- I 4 0 °C 5481 sc l4 - t t -7 9 3 .4 * 0.1 7 .9 ----- I 55 °C 5482 s c l4 - t - 8 93 .1 * 0.1 7 .6 ----- I 55 °C 5483 s c l4 - t - 9 88 .3 * 0.1 7 .7 ----- I 55 °C 5484 s c l4 - t t -1 0 100 * 0.1 7 .6 ----- I 7 0 °C 5485 s c l 4 - t t - l l 9 3 .4 * 0.1 7 .4 ----- I 7 0 °C 5486 s c l4 - t t -1 2 90 .1 * 0.1 7 .6 ----- I 7 0 0C 5721 ts c l4 1 109 * 0.1 9 .4 3.21 I 25 °C 57 2 2 t s c l4 2 121 * 0.1 9 .5 4 .7 3 I 25 °C 5723 t s c l4 3 104 * 0.1 9 .4 3 .45 I 25 °C T ests 5 4 8 7 - 5 4 9 8 had an average m oisture gain o f 1.34% (cond ition ed 1,2 0 0 hours in 5 0 '3C water (D I)) 5 487 w -s c l4 - t t - l 7 6 .2 * 0.1 8 .6 — I 25 0C 5488 w -s c l4 - t t -2 70 .1 * 0.1 8 .2 ----- I 25 °C 5489 w -sc l4 -t t -3 69 .9 * 0.1 7 .8 ----- I 25 °C 435 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE ID # STRESS M Pa H z GPa % TO FA IL (mm) and N o tes 5 4 90 w -s c l4 - t t -4 7 3 .9 * 0.1 7 .5 I 4 0 °C 5491 w -s c l4 -t t -5 68 .3 * 0.1 7.1 ———— I 4 0 °C 5492 w -sc l4 - t t -6 7 6 .9 * 0.1 7.1 ———— I 40 °C 5493 w -s c l4 -t t -7 68 .1 * 0.1 6 .3 ———— I 55 0C 5494 w -s c l4 -t t -8 66 .1 * 0.1 6 .8 ———— I 55 °C 5495 w -sc l4 - t t -9 71 .1 * 0.1 6 .3 ——— I 55 °C 5496 w -sc l4 - t t -1 0 6 6 .8 * 0.1 5 .2 ———— I 70 °C 5497 w -sc I4 - t t - l I 6 7 .3 * 0.1 5.1 ———— I 70 °C 5498 w -sc l4 - t t -1 2 7 0 .4 * 0.1 5 .5 ———— I 70 0C Lay-up = [± 4 5 ]3, Vp = 0 .3 6 , A v e . th ickness = 3 .1 2 mm , S .D . = 0 .0 8 mm , SC -14 E poxy 5 499 s c l4 - 4 5 t - l 9 2 * 0.1 9 .6 ———— I 25 °C 55 0 0 sc 14-451-2 8 7 .6 * 0.1 9 .2 ——— I 25 0C 5501 s c l4 -4 5 t -3 9 2 .7 * 0.1 8 .8 ———— I 25 °C 55 0 2 s c l4 -4 5 t -4 85 .9 * 0.1 8 .6 ——— I 40 °C 5503 s c l4 -4 5 t -5 84 * 0.1 7 .4 ———— I 40 °C 5504 s c l4 -4 5 t - 6 85.1 * 0.1 7 .7 ——— I 40 °C 5505 s c l4 -4 5 t -7 7 5 .7 * 0 .1 6 .4 ——— I 55 °C 5506 s c l4 -4 5 t -8 7 9 .9 * 0 .1 7 .1 — I 55 0C 5507 s c l4 -4 5 t -9 7 4 .7 * 0.1 6 .9 ———— I 55 °C 5508 sc 14-451-10 6 4 .2 * 0.1 6 .4 —— I 70 °C 5509 s c l4 - 4 5 t - l I 7 3 .6 * 0.1 6 .7 ———— I 70 0C 5510 sc 14 -451-12 6 4 .9 * 0.1 5 .7 ——— I 70 °C T ests 5511 - 5 5 2 2 had an average m oisture gain o f 1.24% (cond ition ed 1,2 0 0 hours in 5 0 '3C water (D I)) 5511 w - s c l4 4 5 t l 93 .1 * 0.1 8.1 ———— I 25 °C 5512 w -s c l4 4 5 t2 81 .4 * 0.1 7 .8 —— I 25 °C 5513 w -s c l4 4 5 t3 89 * 0 .1 8 .2 ——— I 25 0C 5514 w -s c l4 4 5 t4 84 * 0.1 7 .2 ———— I 40 °C 5515 w -s c l4 4 5 t5 7 3 .7 * 0 .1 6 .8 ———— I 40 0C 5516 w -s c l4 4 5 t6 7 5 .4 * 0.1 6 .5 ——— I 40 0C 5517 w -s c l4 4 5 t7 6 6 .4 * 0.1 6.1 ---— I 55 0C 5518 w -s c l4 4 5 t8 6 7 .6 * 0.1 6 .0 ——— I 55 °C 5519 w -sc 14 4 5 19 65 * 0 .1 5 .7 ——— I 55 °C 5 5 2 0 w - s c l 4 4 5 t l0 55 * 0.1 4 .0 ——— I 7 0 °C 5521 w - s c l 4 4 5 t l l 5 1 .9 * 0.1 3 .8 I 7 0 °C 5522 w - s c l 4 4 5 t l2 4 9 .5 * 0.1 3 .5 ———— I 70 0C Lay-up = [0 /± 4 5 /0 ]s, V f = 0 .3 6 , A v e . th ickness = 3 .1 6 mm , S .D . = 0 .11 mm , D erakane 8 0 8 4 v inyl ester 5523 8 0 8 4 -t - l 6 98 * 0.1 2 4 .9 — I 25 0C 5524 8084-1-2 6 8 4 * 0.1 25 .1 — — I 25 0C 5525 8084-1-3 539 * 0.1 2 3 .9 — —— I 25 0C 5526 8084 -t-4 4 8 0 * 0.1 2 2 .9 — I 40 °C 5527 8084-1-5 471 * 0.1 2 4 .0 — —— I 4 0 0C 5528 8084-1-6 5 5 0 * 0.1 2 4 .4 — I 4 0 °C 5529 8084-1-7 5 3 2 * 0.1 2 4 .4 — I 55 °C 5530 8084 -t-8 6 5 6 * 0.1 2 3 .6 ———— I 55 0C 5531 8084-1-9 5 8 8 * 0.1 24 .1 ———— I 55 0C 5532 8084 -t-1 0 55 6 * 0.1 2 3 .5 ———— I 70 0C 5533 8 0 8 4 - t - l I 5 3 6 * 0.1 2 2 .5 I 7 0 °C 55 3 4 8 0 8 4 - t - l 2 5 5 0 * 0.1 22 .3 — I 70 0C 4 3 6 TEST & M AX . R Q E e CYCLES W IDTH SAM PLE ID # STRESS M Pa H z GPa % TO FA IL (mm) and N o tes T ests 5 5 3 5 - 5 5 4 6 had an average m oisture gain o f 0 .44% (cond ition ed 1,2 0 0 hours in 5 0 °C water (D I)) 5535 w-8084-t-1 461 * 0.1 25.6 ———— I 25 0C 5536 w-8084-t-2 463 * 0.1 25.1 ———— I 25 °C 5537 w-8084-t-3 472 * 0.1 24.3 ———— I 25 0C 5538 w-8084-t-4 443 * 0.1 24.6 ———— I 40 °C 5539 w-8084-t-5 435 * 0.1 23.6 ———— I 40 0C 5540 w-8084-t-6 436 * 0.1 24.8 —— — I 40 °C 5541 w-8084-t-7 423 * 0.1 23.9 ———— I 55 0C 5542 w-8084-t-8 419 * 0.1 24.9 ———— I 55 0C 5543 w-8084-t-9 413 * 0.1 26.2 ———— I 55 °C 5544 w-8084-t-10 379 * 0.1 23.8 ———— I 70 °C 5545 w-8084-t-ll 397 * 0.1 24.2 ———— I 70 °C 5546 w-8084-t-12 393 * 0.1 24.4 ———— I 70 0C 5547 8084-c-l -600 * 13 ———— ———— I 25 0C 5548 8084-C-2 -569 * 13 ———— ———— I 25 °C 5549 8084-C-3 -611 * 13 —— — ———— I 25 0C 5550 8084-C-4 -494 * 13 ———— ———— I 40 °C 5551 8084-C-5 -478 * 13 — ———— I 40 °C 5552 8084-C-6 -470 * 13 — —— ——— I 40 0C 5553 8084-C-7 -464 * 13 — — ———— I 55 0C 5554 8084-C-8 -444 * 13 ———— ———— I 55 °C 5555 8084-C-9 -455 * 13 ———— ———— I 55 0C 5556 8084-c-lO -445 * 13 ———— ———— I 70 0C 5557 8084-c-l I -444 * 13 ———— — —— I 70 °C 5558 8084-c-l 2 -449 * 13 ———— ———— I 70 °C Tests 5559 - 5570 had an average moisture gain of 0.42% (conditioned 1,200 hours in 50 °C water (DI)) 5559 w-8084-c-l -521 * 13 — —— ———— I 25 °C 5560 w-8084-c-2 -492 * 13 ———— ———— I 25 0C 5561 w-8084-c-3 -513 * 13 ———— ———— I 25 °C 5562 w-8084-c-4 -487 * 13 —— — ———— I 40 °C 5563 w-8084-c-5 -502 * 13 ———— ———— I 40 °C 5564 w-8084-c-6 -450 * 13 ———— ———— I 40 °C 5565 w-8084-c-10 -431 * 13 — — —— — I 55 0C 5566 w-8084-c-l I -466 * 13 —— —— — I 55 0C 5567 w-8084-c-12 -465 * 13 ———— ———— I 55 0C 5568 w-8084-c-7 -414 * 13 ———— ———— I 70 0C 5569 w-8084-c-8 -435 * 13 ———— ———— I 70 °C 5570 w-8084-c-9 -388 * 13 — — I 70 °C Lay-up = [90/±45/90]s, Vf= 0.36, Ave. thickness =3.15 mm, S.D. = 0.10 mm, Derakane 8084 vinyl ester 5571 8084-tt-l 79.5 * 0.1 12.8 — I 25 °C 5572 8084-tt-2 82.8 * 0.1 12.3 ———— I 25 °C 5573 8084-U-3 82 * 0.1 13.0 ———— I 25 °C 5574 8084-U-4 87.2 * 0.1 11.0 ———— I 40 0C 5575 8084-U-5 82.6 * 0.1 10.7 ———— I 40 0C 5576 8084-tt-l 3 62.6 * 0.1 10.4 — I 40 °C 5577 8084-tt-7 80.5 * 0.1 8.3 ———— I 55 °C 5578 8084-U-8 89.4 * 0.1 8.2 --------- I 55 0C 5579 8084-U-9 83.1 * 0.1 7.9 ———— I 55 °C 5580 8084-tt-lO 58.3 * 0.1 6.2 ———— I 70 0C 437 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS ID # MPa Hz GPa % TO FAIL (mm) and Notes 5581 8084-tt-11 59.3 * 0.1 6.2 I 70 °C 5582 8084-U-12 57.6 * 0.1 6.2 —— I 70 0C 5724 180841 62.7 * 0.1 8.6 3.7 I 25 °C 5725 180842 62.9 * 0.1 8.3 4.4 I 25 °C 5726 180843 63.3 * 0.1 8.1 4.2 I 25 °C Tests 5583 - 5594 had an average moisture gain of 0.44% (conditioned 1,200 hours in 50 ‘2C water (DI)) 5583 w-8084-tt-l 47.5 * 0.1 8.4 —— I 25 °C 5584 w-8084-tt-2 48.4 * 0.1 8.5 —— I 25 0C 5585 W-8084-U-3 49.5 * 0.1 8.3 —— I 25 °C 5586 w-8084-tt-4 51.3 * 0.1 8.3 —— I 40 °C 5587 w-8084-tt-5 49.5 * 0.1 7.4 —— I 40 0C 5588 w-8084-tt-6 49.7 * 0.1 8.0 —— I 40 0C 5589 w-8084-tt-7 49.2 * 0.1 7.3 —— I 55 0C 5590 W-8084-U-8 53.1 * 0.1 7.3 —— I 55 0C 5591 W-8084-U-9 45.7 * 0.1 7.4 —— I 55 °C 5592 w-8084-tt-10 53.4 * 0.1 6.6 — I 70 °C 5593 w-8084-tt-l I 51.2 * 0.1 7.0 —— I 70 °C 5594 w-8084-tt-12 52 * 0.1 6.8 —— I 70 °C Lay-up = [±45]3, Vp = 0.36, Ave. thickness =3.12 mm, S.D. =0.08 mm, Derakane 8084 vinyl ester 5595 8084-451-1 122 * 0.1 9.7 —— I 25 °C 5596 8084-451-2 134 * 0.1 10.4 —— I 25 °C 5597 8084-45t-3 125 * 0.1 10.8 —— I 25 °C 5598 8084-451-4 118 * 0.1 9.0 —— I 40 °C 5599 8084-45t-5 117 * 0.1 9.6 — I 40 °C 5600 8084-45t-6 116 * 0.1 9.3 —— I 40 °C 5601 8084-45t-7 113 * 0.1 8.7 —— I 55 °C 5602 8084-45t-8 114 * 0.1 8.6 —— I 55 °C 5603 8084-45t-9 113 * 0.1 8.5 —— I 55 °C 5604 8084-451-10 100 * 0.1 7.4 —— I 70 0C 5605 8084-451-11 104 * 0.1 7.8 I 70 0C 5606 8084-451-12 103 * 0.1 7.3 —— I 70 0C Tests 5607 - 5618 had an average moisture gain of 0.38% (conditioned 1,200 hours in 50°C water (DI)) 5607 w-8084-45t-l 115 * 0.1 10.3 I 25 °C 5608 w-8084-45t-2 115 * 0.1 10.1 I 25 0C 5609 w-8084-45t-3 116 * 0.1 10.3 —— I 25 0C 5610 w-8084-45t-4 108 * 0.1 9.6 — I 40 °C 5611 w-8084-45t-5 112 * 0.1 10.1 — I 40 °C 5612 w-8084-45t-6 HO * 0.1 9.7 —— I 40 0C 5613 w-8084-45t-7 102 * 0.1 9.1 —— I 55 0C 5614 w-8084-45t-8 102 * 0.1 9.4 I 55 0C 5615 w-8084-45t-9 101 * 0.1 9.4 — I 55 °C 5616 w-8084-45t-10 95 * 0.1 8.0 — I 70 °C 5617 w-8084-45t-l I 88 * 0.1 7.3 —— I 70 °C 5618 w-8084-45t-12 94 * 0.1 7.8 — I 70 °C Lay-up = [0/±45/0]s, Vf = 0.36, Ave. thickness = 3.16 mm, S.D. = 0.11 mm, CoRezyn -AQ-051 Iso-Polyester 5619 tp-t-1 694 * 0.1 24.9 — I 25 °C 5620 tp-t-2 652 * 0.1 23.8 — I 25 °C 5621 tp-t-3 557 * 0.1 23.9 — I 25 0C 5622 tp-t-4 656 * 0.1 23.9 I 40 °C 438 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes 5623 tp-t-5 578 * 0.1 25.3 I 40 °C 5624 tp-t-6 646 * 0.1 25.0 --- I 40 °C 5625 tp-t-7 629 * 0.1 23.8 — I 55 °C 5626 tp-t-8 607 * 0.1 24.0 — I 55 °C 5627 tp-t-9 660 * 0.1 24.2 —— I 55 °C 5628 tp-t-10 601 * 0.1 24.2 I 70 °C 5629 tp-t-11 529 * 0.1 23.5 — I 70 °C 5630 tp-t-12 601 * 0.1 23.0 —— I 70 0C Tests 5631 - 5642 had an average moisture gain of 0.5% (conditioned 430 hours in 50 °C water (DI)) 5631 w-tp-t-1 582 * 0.1 26.6 — I 25 °C 5632 w-tp-t-2 635 * 0.1 24.1 —— I 25 °C 5633 w-tp-t-3 531 * 0.1 25.5 — I 25 °C 5634 w-tp-t-4 618 * 0.1 25.0 —— I 40 °C 5636 w-tp-t-6 628 * 0.1 25.0 — I 40 °C 5637 w-tp-t-7 609 * 0.1 24.9 —— I 55 °C 5638 w-tp-t-8 599 * 0.1 25.2 —— I 55 °C 5639 w-tp-t-9 618 * 0.1 25.0 —— I 55 °C 5640 w-tp-t-10 557 * 0.1 22.8 —— I 70 °C 5641 w-tp-t-11 553 * 0.1 24.4 — I 70 °C 5642 w-tp-t-12 541 * 0.1 23.0 — I 70 0C 5643 tp-c-1 -531 * 13 — —— I 25 °C 5644 tp-c-2 -574 * 13 —— --— I 25 °C 5645 tp-c-3 -626 * 13 — I 25 °C 5646 tp-c-4 -559 * 13 — — I 40 °C 5647 tp-c-5 -525 * 13 —-- — I 40 °C 5648 tp-c-6 -569 * 13 — — I 40 °C 5649 tp-c-7 -545 * 13 — —— I 55 °C 5650 tp-c-8 -536 * 13 — — I 55 °C 5651 tp-c-9 -540 * 13 — —— I 55 °C 5652 tp-c-10 -494 * 13 —— — I 70 °C 5653 tp-c-11 -500 * 13 — —— I 70 °C 5654 tp-c-12 -494 * 13 — —— I 70 °C Tests 5655 - 5666 had an average moisture gain of 0.5% (conditioned 430 hours in 50 °C water (DI)) 5655 w-tp-c-1 -595 * 13 — — I 25 °C 5656 w-tp-c-2 -583 * 13 — — I 25 °C 5657 w-tp-c-3 -547 * 13 — — I 25 °C 5658 w-tp-c-4 -534 * 13 — I 40 °C 5659 w-tp-c-5 -495 * 13 — — I 40 °C 5660 w-tp-c-6 -580 * 13 — -------- I 40 0C 5661 w-tp-c-10 -476 * 13 — — I 55 °C 5662 w-tp-c-11 -514 * 13 — — I UV-)V-) 5663 w-tp-c-12 -539 * 13 — — I 55 0C 5664 w-tp-c-7 -480 * 13 — — I 70 °C 5665 w-tp-c-8 -499 * 13 — — I 70 °C 5666 w-tp-c-9 -509 * 13 — — I 70 0C Lay-up = [90/±45/90]s,Vf = 0.36, Ave. thickness = 3.15 mm, S.D. = 0.10 mm, CoRezyn Iso-Polyester 5667 tp-tt-1 67.8 * 0.1 9.2 — I 25 °C 5668 tp-tt-2 68.4 * 0.1 9.0 — I 25 °C 5669 tp-tt-3 64.8 * 0.1 9.3 — — I 25 °C 4 3 9 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS Hz GPa % TO FAIL (mm) ID # MPa and Notes 5670 tp-tt-4 71.7 * 0.1 8.3 I 40 °C 5671 tp-tt-5 68.5 * 0.1 8.8 — I 40 0C 5672 tp-tt-6 68.1 * 0.1 8.3 — I 40 0C 5673 tp-tt-7 64.4 * 0.1 7.7 — I 55 0C 5674 tp-tt-8 69.9 * 0.1 7.9 — I 55 0C 5675 tp-tt-9 68.8 * 0.1 7.9 — I 55 0C 5676 tp-tt-10 69.1 * 0.1 7.4 — I 70 °C 5677 tp-tt-11 71.7 * 0.1 7.2 — I 70 0C 5678 tp-tt-12 70.3 * 0.1 7.4 — I 70 °C Tests 5679 - 5690 had an average moisture gain of 0.5% (conditioned 430 hours in 50 °C water (DI)) 5679 w-tp-tt-1 64.8 * 0.1 9.4 — I 25 °C 5680 w-tp-tt-2 68.8 * 0.1 9.7 — I 25 °C 5681 w-tp-tt-3 66.6 * 0.1 9.1 — I 25 °C 5682 w-tp-tt-4 66.6 * 0.1 9.0 —— I 40 °C 5683 w-tp-tt-5 69 * 0.1 9.1 — I 40 0C 5684 w-tp-tt-6 70.8 * 0.1 9.0 — I 40 0C 5685 w-tp-tt-7 67.9 * 0.1 8.5 — I 55 0C 5686 w-tp-tt-8 66.3 * 0.1 8.9 — I 55 0C 5687 w-tp-tt-9 61.6 * 0.1 8.4 — I 55 0C 5688 w-tp-tt-10 64.6 * 0.1 7.6 —— I 70 °C 5689 w-tp-tt-11 66.2 * 0.1 7.6 — I 70 0C 5690 w-tp-tt-12 67.7 * 0.1 7.1 — I 70 0C Lay-up = [±45]3, Vp = 0.36, Ave. thickness = 3.12 mm, S.D. =0.08 mm, CoRezyn Iso-Polyester 5691 tp-45t-l 133 * 0.1 11.5 —— I 25 0C 5692 tp-45t-2 135 * 0.1 12.3 --— I 25 °C 5693 tp-45t-3 132 * 0.1 11.2 — I 25 °C 5694 tp-45t-4 124 * 0.1 11.5 — I 40 0C 5695 tp-45t-5 127 * 0.1 10.7 — I 40 0C 5696 tp-45t-6 128 * 0.1 10.0 — I 40 °C 5697 tp-45t-7 116 * 0.1 10.1 — I 55 0C 5698 tp-45t-8 116 * 0.1 10.2 — I 55 0C 5699 tp-45t-9 114 * 0.1 10.0 — I 55 0C 5700 tp-45t-10 93.2 * 0.1 8.9 — I 70 0C 5701 tp-45t-ll 93.2 * 0.1 9.6 — I 70 0C 5702 tp-45t-12 100 * 0.1 8.8 — I 70 0C Tests 5703 - 5714 had an average moisture gain of 0.28% (conditioned 430 hours in 50 0C water (DI)) 5703 w-tp-45t-l 131 * 0.1 11.9 — I 25 0C 5704 w-tp-45t-2 125 * 0.1 12.0 I 25 °C 5705 w-tp-45t-3 132 * 0.1 12.1 — I 25 0C 5706 w-tp-45t-4 124 * 0.1 11.3 — I 40 0C 5707 w-tp-45t-5 126 * 0.1 10.8 — I 40 °C 5708 w-tp-45t-6 122 * 0.1 10.5 — I 40 °C 5709 w-tp-45t-7 114 * 0.1 10.0 — I 55 0C 5710 w-tp-45t-8 107 * 0.1 9.9 --- I 55 °C 5711 w-tp-45t-9 HO * 0.1 9.2 — I 55 °C 5712 w-tp-45t-10 94.8 * 0.1 7.7 — I 70 °C 5713 w-tp-45t-ll 96.8 * 0.1 7.5 — I 70 0C 5714 w-tp-45t-12 102 * 0.1 8.9 — I 70 °C 4 4 0 T ests 5 7 3 9 through 5 8 38 in vo lv ed (0 /± 4 5 /0 ) lam inates w ith D 1 5 5 /D B 1 2 0 and A 1 3 0 /D B 1 2 0 fabrics. T hese lam inates w ere p laced in d istilled water and m onitored for m oisture absorption and u ltim ate com pressive strength changes w ith moisture content. T w o o f th ese lam inates w ere taken ou t o f the water, bonded back-to- back, and com pression tested. The back-to-back configuration gave the coupon added buck lin g resistance and sim ulated M ateria l D D 5P (d enoted w ith a “D ”) and M aterial D D l I (d enoted w ith an “A ”). S ee R ef. 18. TEST & MAX. R Q E e CYCLES Test SAMPLE STRESS Hz GPa % TO FAIL Temperature ID # MPa Tests 5739 - 5746 control group, no moisture conditioning, after 24 hours at 40 °C 5739 D6456 -497 * 13 — ———— I 25 °C 5740 D6327 -565 * 13 — ———— I 25 °C 5741 D6533 -532 * 13 — ———— I 25 0C 5742 D6212 -476 * 13 -------— ———— I 25 °C 5743 A6034 -274 * 13 — —- ———— I 25 °C 5744 A6140 -302 * 13 — —— ———— I 25 °C 5745 A5962 -211 * 13 ———— ———— I 25 °C 5746 A5974 -272 * 13 ———— ———— I 25 0C Tests 5747-5754 were tested after 24 hours in 40 0C water, (D-0.20% moisture gain, A-0.29% moisture gain) 5747 D6229 -492 * 13 — — I 25 °C 5748 D6517 -529 * 13 ——— ———— I 25 °C 5749 D6559 -533 * 13 — —— ———— I 25 °C 5750 D5866 -509 * 13 ——— — — I 25 °C 5751 A6046 -239 * 13 —— ——— I 25 °C 5752 A6236 -334 * 13 ——— — —— I 25 °C 5753 A6141 -272 * 13 ——— ———— I 25 °C 5754 A6147 -205 * 13 — ——— I 25 0C Tests 5755-5765 were tested after 144 hours in 40 0C water, (D-0.47% moisture gain, A-0.54% moisture gain) 5755 D6229 -665 * 13 — — I 25 °C 5756 D6194 -464 * 13 ——— — —— I 25 °C 5757 D6112 -517 * 13 — ——— I 25 °C 5758 D6205 -464 * 13 ———— I 25 °C 5759 A6070 -250 * 13 ———— I 25 °C 5760 A6090 -314 * 13 ———— -------— I 25 °C 5761 A6236 -288 * 13 — —— I 25 0C 5762 A5950 -295 * 13 — —— I 25 °C 5763 D6441 -519 * 13 —— — — I 0 0C 5764 D6365 -486 * 13 — —— ———— I 0 0C 5765 D6369 -452 * 13 — —— — I 0 °C Tests 5766-5765 were tested after 1315 hours in 40 °C water,(D-0.61% moisture gain, A-0.73% moisture gain) 5766 D6443 -471 * 13 — — I 25 °C 5767 D6489 -519 * 13 ———— — —— I 25 0C 5768 D6846 -474 * 13 — —— I 25 0C 5769 D6590 -420 * 13 — — I 25 0C 5770 A6570 -213 * 13 ———— I 25 °C 5771 A5976 -211 * 13 — — I 25 0C 5772 A6021 -260 * 13 — — --------- I 25 °C 5773 A6228 -191 * 13 —— I 25 °C Tests 5774-5779 control group, no moisture conditioning, after 1315 hours at 40 0C 5774 D6490 -509 * 13 — — I 25 0C 5775 D6370 -404 * 13 ———— — —— I 25 0C 5776 D5924 -621 * 13 —— — — — I 25 °C 441 TEST & MAX. R Q E e CYCLES Test SAMPLE ID # STRESS MPa Hz GPa % TO FAIL Temperature 5777 A6119 -283 * 13 I S n 5778 A5980 -261 * 13 ———— ———— I 25 °C 5779 A6007 -279 * 13 — I 25 °C Tests 5780-5786 control group, no moisture conditioning, after 2000 hours at 40 °C, 2650 hours at 20 °C 5780 D6210 -560 * 13 ................. I 25 °C 5781 D6401 -568 * 13 ———— ———— I 25 0C 5782 D6219 -539 * 13 ———— —— — I 25 °C 5783 A5970 -218 * 13 — —— ———— I 25 0C 5784 A6070 -307 * 13 ———— ———— I 25 0C 5785 A5983 -300 * 13 — — I 25 °C Tests 5786-5801 were tested after 2000 hours in 40 °C water and 2650 hours in 20 °C water, (D-0.62% moisture gain, A-0.64% moisture gain) 5786 D6212 -405 * 13 I 25 °C 5787 D6220 -393 * 13 ———— — —— I 25 °C 5788 D6171 -473 * 13 -------— ———— I 25 0C 5789 D6794 -413 * 13 ———— ———— I 25 0C 5790 D5978 -352 * 13 — —— —— —— I 50 °C 5791 D6349 -414 * 13 ———— ———— I 50 °C 5792 D6491 -423 * 13 ———— ———— I 50 °C 5793 D6270 -423 * 13 ———— — —— I 50 °C 5794 A6008 -228 * 13 ———— — —— I 25 °C 5795 A6506 -267 * 13 — — ———— I 25 °C 5796 A6119 -240 * 13 —— — — I 25 °C 5797 A6034 -224 * 13 ———— ———— I 25 °C 5798 A6149 -176 * 13 — — I 50 °C 5799 A6396 -125 * 13 —— — —— I 50 °C 5800 A6223 -216 * 13 ———— ———— I 50 0C 5801 A6149 -179 * 13 —— — ———— I 50 °C Tests 5802-5817 were tested after 2000 hours in 40 0C water and 13355 hours in 20 °C water, (D-0.97% moisture gain, A-l.01% moisture gain) 5 802 D 622 3 -4 42 * 13 — ----- I 25 0C 5803 D 688 3 -4 06 * 13 — ----- I 25 °C 58 0 4 D 60 3 7 -4 04 * 13 — ----- I 25 °C 5805 D 5 9 9 2 -3 66 * 13 ———— ----- I 25 °C 58 0 6 A 6 0 2 6 -163 * 13 — ----- I 25 °C 5807 A 5 9 7 2 -215 * 13 ———— ----- I 25 0C 5808 A 6 1 8 8 -2 29 * 13 ———— ----- I 25 °C 5809 A 6061 -203 * 13 ——— ----- I 25 °C 58 1 0 D 5 8 6 4 -3 77 * 13 ---— ----- I 5 0 0C 5811 D 5 9 6 0 -3 3 2 * 13 ———— ----- I 5 0 0C 58 1 2 D 5 8 4 2 -3 09 * 13 — ----- I 5 0 °C 5813 D 6 3 1 6 -375 * 13 ——— ----- I 5 0 0C 5814 A 59 7 5 -1 3 2 * 13 ——— ----- I 5 0 0C 5815 A 62 1 8 -1 54 * 13 ----- I 5 0 0C 5 8 1 6 AS 894 -1 8 8 * 13 ———— ----- I 5 0 0C 5817 A 61 6 5 -225 * 13 ———— ----- I 5 0 0C T ests 5 8 1 8 -5 7 8 6 contro l group, no m oisture cond ition in g , after 2 0 0 0 hours at 4 0 0C , 13355 hours at 2 0 5818 D 6 3 9 4 -4 4 8 * 13 ———— — I 25 cC 5819 D 6 2 4 8 -361 * 13 ———— I 25 °C 442 TEST & MAX. R Q E e CYCLES Test SAMPLE ID # STRESS MPa Hz GPa % TO FAIL Temperature 5820 D6265 -434 * 13 I 25 0C 5821 D6472 -583 * 13 — —— ———— I 25 °C 5822 D6485 -532 * 13 — —— —— —— I 25 °C 5823 D6428 -559 * 13 ———— ———— I 25 °C 5824 D6183 -516 * 13 — — — I 50 °C 5825 D6351 -468 * 13 —- — ———— I 50 °C 5826 D6217 -542 * 13 — —— —— I 50 °C 5827 D6411 -430 * 13 — — ———— I 50 0C 5828 D6530 -405 * 13 — — ——— I 50 °C 5829 A6040 -250 * 13 — —— I 25 °C 5830 A6161 -283 * 13 — —— ———— I 25 °C 5831 A6008 -298 * 13 ——— ———— I 25 °C 5832 A6036 -222 * 13 — — —— I 25 °C 5833 A5911 -249 * 13 — ———— I 25 °C 5834 A5951 -251 * 13 -------— ——— I 50 0C 5835 A6259 -270 * 13 ———— — — I 50 °C 5836 A6079 -232 * 13 — —— ——— I 50 °C 5837 A6420 -264 * 13 — ———— I 50 °C 5838 A6056 -233 * 13 These tests are summarized in the two tables below [18]. — I 50 0C Compression Testing Summary of Coupons (0/±45/0) Exposed to 20 - 40 0C Distilled Water (D155 and A130 O0 fabric with DB 120 ±45° fabric, Vf = 0.34) Exposure Time, hours Test Temperature, °C Average Moisture Gain (S.D.), % D155Ave. strength (S.D.), psi % Change A130 Ave. strength (S.D.), psi % ChangeD155 A130 0 20 0 0 517(39) — 265 (39) — 24 20 0.20 (0.01) 0.29 (0.03) 516(19) -0.3 262 (55) -0.8 144 20 0.47 (0.01) 0.54 (0.02) 481 (30) -6.9 286 (27) 8.4 1,315 20 0.61 (0.06) 0.73 (0.04) 471(35) -9.0 219 (26) -17 4,650 20 0.62 (0.11) 0.64 (0.08) 420(31) -19 240(17) -9.3 4,650 50 0.62 0.64 403 (30) -15 174 (32) -30 15,355 20 0.94 (0.25) 1.02 (0.05) 404 (31) -22 202 (28) -23 15,355 50 0.99 (0.22) 0.99 (0.04) 348 (34) -26 175 (40) -30 Baseline D155 modulus = 24.8 GPa, Baseline A130 modulus = 23.7 GPa at 1% moisture - D155 = 24.8 GPa, at 1% moisture - A130 = 19.9 GPa Coupons were tested in a double thickness configuration at 13 mm/s with a 13 mm gage length. 443 Compression Testing Summary of Dry Control Coupons (0/±45/0) (D155 and A130 O0 fabric with DB 120 ±45° fabric, Vf= 0.34) Exposure Time, hours TestingTemperature, 0C D155 Ave. strength (S.D.), MPa % Change A130 Ave. strength (S.D.), MPa % Change 0 20 517 (39) — 265 (39) — 1,315 dry control 20 511(89) -1.2 274(10) +3.8 4,650 dry control 20 556(13) +7.4 275 (40) +3.9 15,355 dry control 20 486 (86) -6.4 260 (30) +1.6 15,355 dry control 50 472 (57) -9.6 250 (17) -5.8 DD5P Environmental Tests Tests 4880 - 4899, 5860 - 5899 involved full thickness DD5P coupons which were immersed in distilled water for a total of 300 days The first 91 days were at a temperature of 40 °C with the remaining time at room temperature (18-22 °C). These “WET” coupons averaged 1.0 percent moisture absorption at the time of testing. All the tensile coupons in this series were dog boned shaped with a minimum width of 22 mm. The compression coupons were 25 mm wide and involved a gage length of 13 mm. The last column of data lists the temperature that the test was run under, and whether or not the coupon was “DRY” (not soaked in water, -0 % moisture content) or WET (coupons that were soaked in distilled water, as described above). See Reference 18. MATERIAL DD5P - Environmental Lay-up = [0/±45/0]s, Vf = 0.36, Ave. thickness (dry) = 3.13 mm, S.D. (dry) = 0.004 mm, Ave. thickness (wet) = 2.95 mm, S.D. (dry) = 0.004 mm, CoRezyn 63-AX-051 Polyester TEST & MAX. R Q E e CYCLES Temperature SAMPLE ID # STRESS MPa Hz GPa % TO FAIL and condition 4880 DD5P820 310 0.1 3 21.6 1.62 178,431 50 °C Dry 4881 DD5P816 310 0.1 3 20.8 1.64 233,742 50 °C Dry 4882 DD5P816 310 0.1 3 21.1 1.52 246,075 50 °C Dry 4883 DD5P819 710 * 13 19.5 3.6 I 50 °C Dry 4884 DD5P814 730 * 13 22.3 3.3 I 50 °C Dry 4885 DD5P817 742 * 13 22.3 3.4 I 50 °C Dry 4886 DD5P812 414 0.1 2 22.1 2.21 4,207 50 °C Dry 4887 DD5P821 414 0.1 2 22 2.03 3,614 50 °C Dry 4888 DD5P818 414 0.1 2 21.5 1.86 1,132 50 °C Dry 4891 DD5P908W 241 0.1 5 — — 2,145,373 50 0C Wet 4892 DD5P900W 310 0.1 3 20 1.42 17,971 50 °C Wet 4893 DD5P901W 241 0.1 5 20.6 1.19 1,733,316 50 °C Wet 4894 DD5P902W 241 0.1 5 20.8 1.22 2,033,339 50 °C Wet 4895 DD5P903W 310 0.1 3 21.3 1.51 45,534 50 °C Wet 4896 DD5P904W 310 0.1 3 20 1.54 35,346 50 °C Wet 4897 DD5P905W 693 * 13 21.6 ———— I 50 °C Wet 4898 DD5P907W 688 * 13 22 — I 50 °C Wet 4899 DD5P906W 734 * 13 21 ———— I 50 0C Wet 4 4 4 TEST & MAX. R Q E e CYCLES Temperature SAMPLE ID # STRESS MPa Hz GPa % TO FAIL and condition 5860 DD5P909W -345 10 I 16 50 °C Wet 5861 DD5P910W -426 * 13 —— ———— I 50 °C Wet 5862 DD5P911W -384 * 13 ———— ———— I 50 °C Wet 5863 DD5P912W -401 * 13 —— ———— I 50 °C Wet 5864 DD5P913W -381 * 13 ———— ———— I 50 °C Wet 5865 DD5P914W -276 10 2 ———— ———— 1,410 50 °C Wet 5866 DD5P915W -207 10 2 — — — 37,673 50 °C Wet 5867 DD5P916W -207 10 5 — — — 44,469 50 °C Wet 5868 DD5P917W -207 10 5 — — — 54,737 50 0C Wet 5869 DD5P918W -165 10 8 ———— 190,729 50 0C Wet 5870 DD5P919W -165 10 10 — — —— 342,905 50 °C Wet 5871 DD5P920W -165 10 10 — — 141,564 50 °C Wet 5872 DD5P921 -345 10 I — — — 130 50 0C Dry 5873 DD5P930 -207 10 5 — — 124,290 50 °C Dry 5874 DD5P926 -207 10 5 — — 173,669 50 °C Dry 5875 DD5P929 -207 10 5 — — 482,504 50 °C Dry 5876 DD5P924 -276 10 4 — — 98,038 50 °C Dry 5877 DD5P931 -276 10 5 — — — 74,728 50 °C Dry 5878 DD5P925 -276 10 5 - — - — 49,636 50 0C Dry 5879 DD5P923 -508 * 13 — — I 50 °C Dry 5880 DD5P922 -488 * 13 — — I 50 °C Dry 5881 DD5P927 -500 * 13 — — I 50 °C Dry 5900 DD5P963 -165 10 8 — — 1,109,352 50 °C Dry 5882 DD5P928 -379 10 5 — — 48,127 20 °C Dry 5883 DD5P932 -345 10 5 — — 164,214 20 0C Dry 5884 DD5P933 -345 10 5 — — 288,708 20 °C Dry 5885 DD5P945 -345 10 10 — — 198,403 20 °C Dry 5898 DD5P940 -651 * 13 — — I 20 0C Dry 5886 DD5P944 -578 * 13 — — I 20 °C Dry 5887 DD5P937 -661 * 13 — — — I 20 °C Dry 5892 DD5P936 -632 * 13 — — —— I 20 0C Dry 5888 DD5P957W -523 * 13 I 20 °C Wet 5889 DD5P956W -542 * 13 — I 20 °C Wet 5890 DD5P955W -539 * 13 —— — — I 20 0C Wet 5891 DD5P964W -527 * 13 — ———— I 20 °C Wet 5893 DD5P963W -276 10 5 — — 333,063 20 0C Wet 5894 DD5P958W -310 10 3 — ———— 16,432 20 0C Wet 5895 DD5P959W -276 10 5 — — 836,080 20 °C Wet 5896 DD5P960W -310 10 3 ———— — —— 27,564 20 °C Wet 5897 DD5P961W -310 10 3 — — 22,185 20 °C Wet 5899 DD5P962W -276 10 5 — — - 637,232 20 °C Wet 445 Neat Resin Tests TEST & MAX. R Q E e CYCLES WIDTH SAMPLE STRESS Hz GPa % TO FAIL (mm) ID # MPa and Notes Maximum stress column lists the maximum stress/yield stress. The listed yield stress was determined using the 0.2% strain offset method. CoRezyn 63-AX-051 (Interplastics Corporation) Heat deflection temperature (3 tests) - 53.6 0C1 55.3 0C, 55.1 0C 5842 poly I 59.6/47.4 * 0.1 3.01 2.4 I 11 5843 poly2 48.3/41.7 * 0.1 3.25 1.66 I 11 5844 poly3 54.3/46.5 * 0.1 3.29 1.93 I 11 Derakane 411C-50 (Dow Chemical) Heat deflection temperature (3 tests) - 73.5 0C1 80.2 °C, 79.6 0C 5845 41 ICl 57.2/47.1 * 0.1 3.26 2.02 I 11 5846 411C2 58.8/53.2 * 0.1 3.16 2.14 I 11 5847 411C3 57.1/50.9 * 0.1 3.21 2.02 I 11 Derakane 8084 (Dow Chemical) Heat deflection temperature (3 tests) - 72.6 °C, 74.7 °C, 75.2 0C 5848 80841 75.1/58.4 * 0.1 3.04 3.36 I 11 5849 80842 73.8/54.5 * 0.1 3.33 2.95 I 11 5850 80843 68.8/52.6 * 0.1 3.38 2.6 I 11 System 41 (System Three) Heat deflection temperature (3 tests) - 59.4 °C, 52.9 °C, 53.3 0C 5851 sys31 51.1/51.1 * 0.1 3.59 1.54 I 11 5852 sys32 53.1/53.1 * 0.1 3.63 1.58 I 11 5853 sys33 53.6/53.6 * 0.1 3.49 1.67 I 11 SC-12 (Applied Poleramic Inc.) Heat deflection temperature (3 tests) - 92.7 0C1 94.8 °C, 95.0 °c 5854 scl21 41.1 * 0.1 3.48 1.26 I 11 5855 sc 122 48.5 * 0.1 3.43 1.55 I 11 5856 sc 123 43.4 * 0.1 3.52 1.32 I 11 SC-14 (Applied Poleramic Inc.) Heat deflection temperature (3 tests) - 80.5 0C, 82.7 0C1 84.3 °c 5857 scl41 72.1/50.1 * 0.1 2.83 3.68 I 11 5858 sc142 66.3/46.8 * 0.1 2.76 3.15 I 11 5859 sc143 66.3/48.6 * 0.1 2.82 3.09 I 11 446 List of tests omitted from the database list due to testing irregularities, premature buckling, fiber orientation or gripping problems causing an invalid test. TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes Al 102A 454 * 0.02 I 50 tab A3 101A 423 * 0.02 — ———— I 50 tab A4 103A 347 * ——— — ———— I 50 tab I 104 A 185 0.5 — —— ———— 1,400 50 tab 2 105 A 130 0.1 10 — — 155,201 50 tab 3 106 A 333 0.1 0.5 — ———— 210 50 tab 4 107 A 288 0.1 I — ———— 873 50 tab 5 106B 338 * ——— ——— — ———— 50 tab 8 101B 361 0.1 0.5 — — 1,860 50 tab 10 104B 408 0.1 0.1 — ———— 40 50 tab 11 105B 420 0.1 0.1 — — 160 50 tab 14 IlOB 356 0.1 0.1 — 480 50 tab 19 115B 399 0.1 0.1 18.3 ——— 180 50 tab 94 109 J 188 * — 22.6 0.82 I 25 tab 275 113R 155 0.1 15 ———— — I 50 tab 307 115X 345 0.1 5 25.1 1.42 1,441 25 tab 308 IllX 345 0.1 5 23.6 1.46 2,114 25 tab 324 148X -332 * 13 26.8 2.3 I 25 tab 325 146X -378 * 13 25.9 1.73 I 25 tab 326 149X -326 * 13 24.0 1.39 I 25 tab 327A 190X -365 * 13 ———— ——— I 25 327B 191X -317 * 13 ——— ——— I 25 338 155X -241 10 10 30.9 0.74 2,000 25 tab 448 243AA 241 - I 2 18.9 ———— 17 25 tab 481 273A A — 10 25 — — 91,520 25 tab 698 165 Y -246 10 5 — — 31 25 tab 700 174 Y -246 10 10 25.7 1.07 235 25 tab 703 171X -345 10 2 — ———— 137 25 tab 704 165X -345 10 I — — 178 25 tab 705 177X -310 10 2 ———— ——— 14,129 25 tab Material DD3 had random mat in between the O0and ±45 I Si V f = 0.48, thickness = 2.92 mm, D155 and DB 120 fabrics with an unknown mat specification. 1054 DD3104 792 * 13 29.3 2.70 I 22 1055 DD3106 483 0.1 2 29.0 1.66 687 22 1056 DD3105 483 0.1 2 27.4 1.76 869 22 1057 DD3103 414 0.1 5 27.4 1.50 1,932 22 1058 DD3102 345 0.1 10 — — 6,629 22 1059 DD3101 345 0.1 10 — — 4,909 22 1130 DD7130 -448 * 25 — — I 25 1131 DD7126 -460 * 25 ———— ——— I 25 1132 DD7121 -463 * 25 — I 25 1133 DD7120 -451 * 25 — — I 25 1134 DD6127 -310 10 5 — — 84,387 25 1135 DD6119 -345 10 5 ——— — 13,297 25 1136 DD6120 -345 10 5 — — 10,844 25 1137 DD7123 -345 10 10 — — 89,517 25 447 TEST & MAX. R Q E e CYCLES WIDTH SAMPLE ID # STRESS MPa Hz GPa % TO FAIL (mm) and Notes 1138 DD7122 -345 10 10 73,744 25 1139 DD7125 -345 10 15 -------— ———— 100,821 25 1141 DD6122 -310 10 25 — -------— 110,395 25 1150 DD6134 -480 * 13 ———— ———— I 25 1151 DD6117 -461 * 13 ———— ———— I 25 1152 DD6126 -379 10 10 ———— ——— 6,797 25 1162 DD7127 -379 10 10 ———— ———— 1,735 25 1176 DD6142 -425 * 13 ———— ———— I 25 1177 DD7149 -577 * 13 — —— ———— I 25 1205 DD8107 483 0.1 5 15.0 ———— — 22 1208 DD8110 414 0.1 5 ——— — —— 30 22 1222 DD9115 483 0.1 5 33.4 ———— 17 22 1225 DD9105 276 0.1 5 33.2 Tests 1690-1692 exhibited buckling during the fatigue tests. — 8,873 22 1690 CH12147 -241 10 12 — ———— 18,512 25 1691 CH12134 -241 10 5 ———— 16,872 25 1692 CH12142 -241 10 5 -------— ———— 12,942 25 1845 CC201 -166 * 13 ———— ———— I 25 1846 CC202 -186 * 13 ———— ——— I 25 1847 CC203 -176 * 13 — —— ———— I 25 2020 DI5507 -598 * 13 31.2 -1.94 I ZERO tab 2021 DI5508 -619 * 13 32.0 -1.72 I ZERO tab 3938 DD19A107 -172 10 5 — —— -------— 13,650 25 Z 3939 DD19A105 -172 10 4 Material D155D, Vf = 0.29, has fiber wash and fiber misalignment 652 25 Z 2137 D155D201 680 * 13 25.2 2.8 I 25 2138 D155D205 746 * 13 29.0 2.7 I 25 2139 D155D211 763 * 13 29.3 ———— I 25 2140 D155D210 414 0.1 I 26.1 1.65 —— 25 2213 D155H105 552 0.1 4 35.9 1.54 8,460 25 2214 D155H104 552 0.1 2 28.4 ———— 277 25 2345 D155H115 834 * 13 36.7 ———— I 25 2769 D155G308 -500 10 5 Material IOD155 with a gage length of 100 mm (too short) — 46,980 25 2567 10D155125 172 0.1 5 27.6 0.66 1,747 25 2568 10D155126 172 0.1 5 21.2 0.87 9,287 25 2769 D155G308 -500 10 5 -------— — —— 46,980 25 2785 D092G129 -690 10 I — ———— 4 25 4181 DD25B101 END OF DATABASE 310 0.1 2 16.7 2.12 1,620 22 tab 448 APPENDIX B SUMMARY OF I-BEAM TESTS 449 INDIVIDUAL BEAM TEST DETAILS FOR BEAMS NUMBERS 6 AND HIGHER TABLE OF CONTENTS PAGE Beams With AA Material (Triax) Flanges and CHlO Material Web ..........................451 Beam 6 ............................................................................................................... 451 Beam 7 ............................................................................................................... 455 Beam 8 ............................................................................................................... 460 Beam 9 ............................................................................................................... 461 Beam 1 0 ............................................................................................................. 461 Beam 1 1 ............................................................................................................. 464 Beam 1 2 ............................................................................................................. 467 Beam 1 3 ............................................................................................................. 468 Beam 1 4 ............................................................................................................. 470 Beam 22 ............................................................................................................. 471 Beam 23 ............................................................................................................. 472 Beams With Improved Flange and Web Materials ......................................................473 Beams With DD5P Material Flanges and CHlO Material Webs......................473 Beam 1 8 ................................................................................................. 474 Beam 1 9 ................................................................................................. 475 Beam 20 ................................................................................................. 475 Beam 2 1 ................................................................................................. 478 Beam 24 ................................................................................................. 479 Beam 25 ................................................................................................ 481 Beam 26 ................................................................................................. 482 Beam 27 ................................................................................................. 483 Beam 28 ................................................................................................ 484 Beam 29 ................................................................................................. 485 Beams With DD5P Material Flanges and CH3 Material Webs........................486 Beam 30 ................................................................................................ 487 Beam 31 ................................................................................................. 488 Beam 32 ................................................................................................ 489 Beam 33 ................................................................................................ 490 Beams With DD5P Material Flanges and CH5 Material W ebs........................491 Beam 34 ................................................................................................. 491 Beam 35 ................................................................................................. 493 Beams With DD5P Material Flanges and DD5P Material Webs ....................494 Beam 5 1 ................................................................................................. 494 Beam 52 ................................................................................................. 494 Beam 53 ................................................................................................ 497 Beam 54 ................................................................................................. 498 450 Beams With Structural Details....................................................................................... 499 Beams With Holes in Material AA (Triax) Flanges ........................................ 499 Beam 1 5 ................................................................................................. 500 Beam 1 6 ................................................................................................. 501 Beam 1 7 ................................................................................................. 502 DD27 Material Flanges (with balsa wood) and CHl 2 Web Material............................504 Beam 58 ............................................................................................................ 504 Beam 59 ............................................................................................................ 504 451 AA Material (Triax) Flanges and CHlO Web Material Beams 6 through 17, 22 and 23 all had Material AA (CDB200 Triax fabric) flanges, Vf = 0.42, consisting of a lay up of ((±4570o)2)s, except for Beams 9 and 10, which had the lay up reversed ((07±45°)2)s. The description of the I-beam flange lay up and ply numbering scheme for these beams is outlined in Tables BI and B2. The web was CHlO material, ((±45 0)3)s with DB240 fabric. BEAM 6 Beam 6 was tested statically to failure. The beam was loaded under actuator displacement control at a rate of 0.25 mm/s until failure, which involved a total ramp time of 74 seconds. An initial beam stiffness of 3,711 kN/m was measured. As the beam was loaded, the compression flange started to twist along the X-axis, prior to final compressive failure of the compression flange. The total amplitude of this twist was approximated at 6 to 8 mm prior to failure and the onset of this twisting occurred at approximately 90 to 95 percent of the ultimate load. This twisting was also evident in the failed beam as one side of the beam flange had fragmented ±45 ° strands pointing up, while the other side of the flange had the fragmented strands pointing down. Figures BI and B2 show the failed beam. Further examination of the buckled compression flange indicated that the outside 0° ply (ply 3, Table BI) delaminated first from the adjacent ±45° layer (ply 4, Table BI). This delamination arrested at x = 267 mm, which was evident by the white damage band in the outside plies at this point. It was not evident where the delamination started. From this initial arrest at x = 267 mm, the delamination continued to grow towards both inside compressive load pads at x = 152 mm and x = 464 mm. The web had multiple delaminations under the initial flange failure site generated after the flange, failure. Some delamination spots are visible at x = 191, 267, 343 and 394 mm, at the compression flange-web intersection that could be buckling nodal points. No shear stiffener, torsional stiffener or tension flange damage or delaminatioris were visible. The load-flange absolute maximum strain graph is shown in Figure B3 and indicates a maximum tension flange strain of 1.80 percent and a minimum compression flange strain of -1.6 percent which occurred at an ultimate applied load of 67.08 kN at a maximum mid-span deflection of 22 mm. 452 Table BI. Ply reference notation for Beams 6 through 9,12 through 17, 22 and 23. Ply number Ply angle Fabric Description I +45° 2 -45° CDB200 3 0 ° 4 +45° 5 Oun CDB200 Material AA triax flange, 2.9 mm thick Vf = 0.42 6 0 ° 7 0 ° 8 -45° CDB200 9 +45° 10 0 ° 11 -45° CDB200 12 +45° Adhesive Layer Hysol EA 9309.2NA, 0.1 - 0.4 mm thick -45c +45° -45° DB240 DB240 DB240 Web material CHlO C-channel web flange, 5 mm thick Vf = 0.35 453 Table B2. Ply reference notation for Beams 10 and 11. Ply number Ply angle Fabric Description I O0 CDB200 Material AA2 triax flange, 2.9 mm thick Vf = 0.42 2 -45° 3 +45° 4 0 ° CDB2005 -45° 6 +45° 7 +45° CDB2008 -45° 9 0 ° 10 +45° CDB20011 -45° 12 0 ° Adhesive Layer Hysol EA 9309.2NA, 0.1 - 0.4 mm thick 13 +45° DB240 Web material CHlO C-channel web flange 5 mm thick Vf = 0.35 14 -45° 15 +45° DB24016 -45° 17 +45° DB24018 -45° Triax Flange. Ply 1 Ply 12 WebFIange T1,'.' x I - B e amWeb 454 Compression flange - top view Initial delamination arresting point Failure Figure BI. Beam 6. Figure B2. Beam 6. 455 60 70 -o 50 I E 40s. # 3 0 L < I l l l l l I I mpression Flang - Co — Z"MeIX. a ITdlIl — I . / / T pt Z Max. Strain = 1.8% Z z ZZ Z Z 0.0 0.4 0.6 0.8 1.0 1.2 1.4 Absolute Maximum Flange Strain, % Figure B3. Load versus maximum flange strain, beam 6, static test. BEAM? Beam number 7 was fatigued at a rate of 5 Hz under sinusoidal load control with a maximum load of 24.5 kN and a minimum load of 2.5 kN. The maximum load produced an initial maximum tension flange strain of 0.58 percent and a minimum compression flange strain of -0.56 percent. The initial beam stiffness was measured as 3,398 kN/m. The tensile flange had two additional strain gages on the flange edges to determine the strain distribution across the flange. At a static load of 27 kN, the center strain gage indicated 0.680percent strain, while the edge gages indicated 0.64 percent and 0.63 percent for a combined average strain of 0.65 percent. With the center strain gage directly over the web and the two other gages on the relatively flexible edges, this strain distribution is fairly uniform with only a ±4 percent change across the flange width. Initially, the beam was loaded to 32 kN with readings taken from all the strain gages, including a delta strain gage rosette (0o/120o/240°) centered 9 mm ahead of one of the shear stiffeners on the neutral axis of the beam. The strain rosette (Omega Engineering Inc. SG-3/350/RY11) was utilized to determine the nature of the strains ahead of the stiffener, which was a point of damage on the initial beams (I to 5) and to also aid in finite element modeling of the beam. The initial loading versus flange strain graph is shown in Figure B4 and is typical of all the other triax beams. Both the tension and compression flange indicate the same load- strain slope. The maximum absolute flange strain versus fatigue cycles is shown in Figure B5. The stiffness of the beam decreases during the fatigue test due to matrix cracking and delamination, and under load control, the maximum strain in the beam must increase during the fatigue test. The apparent increase in actuator amplitude, (maximum stroke minus minimum stroke), is shown in Figure B6 and is typical of all the beams tested. The initial strain rosette data is graphically shown in Figure B7. The shear stress 9 mm ahead 456 of the shear stiffener was calculated from this data and is shown in Figure B8. The shear stress is small, but present on the neutral axis of the beam at this point. During the fatigue test, white spots started to form at random locations on the tension flange. These damage nucleation locations involved fiber delamination and fiber breakage involving the stitching cross over points in the fabrics. As the fatigue test continued, the damage sites increased in size and some damage spots coalesced to form failure lines. These sites continued to grow until the worst damage site extended across the tensile flange that caused final failure of the tension flange at 492,147 cycles. The failure site occurred at x = 356 ±5 mm and is shown in Figures B9 and BIO. The flange damage was very localized, while the delamination of the entire flange from the I-beam preform extended from x = 260 to x = 406 mm and was due to the flange failure. The delamination in the beam occurred between the +45° (ply 12, Table BI) and the adhesive, and between the ±45° plies (plies 15,16, Table BI). The failure also caused delaminations to extend 16 mm down into the shear web. No shear stiffener, torsional stiffener or compression flange damage or delaminations were visible. The Instron 8501 displacement interlocks were set so that any actuator travel ±3 mm above the nominal fatigue running displacement would stop the fatigue test and limit any post failure damage from being generated. This procedure was observed for all the beams. i 1 25 .E 20 £ I 15 ompression FlangC x Tension Flange > 0.2 0.3 0.4 0.5 0.6 0.7 Absolute Maximum Flange Strain, % 0.9 Figure B4. Load versus maximum flange strain, beam 7, initial loading. 457 Tension Flange S 0.6 Compression Flange Cycles Figure B5. Maximum flange strain, beam 7. initial loading. Cycles Figure B6. Actuator amplitude versus cycles, beam 7. 458 2 0.02 -0.02 Applied Four Point Load, kN Figure B7. Load versus strain for beam 7, delta strain gage rosette on web. Applied Four Point Load, kN Figure B8. Load versus web shear stress for beam 7, 9 mm ahead of shear stiffener. 459 Tension flange - top view Compression flange ^ Side view 50 mm Figure B9. Beam 7. Figure BIO. Beam 7. 460 BEAMS Beam number 8 was fatigued at a rate of 2 Hz with a maximum load of 31.1 kN and a minimum load of 3.1 kN. The maximum load produced an initial maximum tension flange strain of 0.79 percent and a minimum compression flange strain of -0.70 percent. The initial beam stiffness was measured as 3,499 kN/m. As with Beam 7, white damage spots were generated on the tension flange during the fatigue test. At 29,051 cycles, the tensile flange failed and separated at x = 324 ± 9 mm, which caused the flange to delaminate from the preform between x = 255 to x = 368 mm and is shown in Figures BI I and B12. The delamination involved extensive fiber bridging between the inside flange +45° (ply 12, Table BI) and the adhesive on the preform. This beam was fatigued at a higher strain than Beam 7 and thus had more internal strain energy stored in it prior to failure, which is apparent by the amount of damage generated in the web as compared to Beam 7. The web delamination extended 45 mm from the tension flange and was located at x - 324 ± 44 mm. No shear stiffener, torsional stiffener or compression flange damage or delaminations were visible. Tension flange - top view Delamination-v. Compression Aangey^ 50 mm Figure BH. Beam 8. Interior web delamination / Tension flange Figure B12. Beam 8. 461 BEAM 9 Beam 9 involved a static test. The beam was loaded under actuator displacement control at a rate of 0.25 mm/s until failure, which involved a total ramp time of 43 seconds. An initial beam stiffness of 3,556 KN/m was measured. Beams 9 and 10 were constructed with the 0° plies on the outside (Material AA2) of the flange rather than the +45° (Material AA). This layup reversal did not significantly affect the stiffness of the beam when compared to the other beams. It was apparent, after the static test, that there was substantial fiber waviness in the fabric that caused the beam to fail prematurely. Curved fiber tows, with a radius of 4 to 5 mm, turned white as they delaminated from the material around them on both the tension and compression flanges. Figures B13 and B14 show the failed beam. The ultimate load that the beam held was 59.2 kN and corresponded to a maximum tension flange strain of 1.78 percent and a minimum compression flange strain of -1.80 percent. The load versus maximum strain graph is shown in Figure B15. The buckling failure of the compression flange occurred at two sites: x = 260 ± 6 mm on the flange and x = 298 ± 10 mm on the preform. Delamination of the flange from the web flange occurred from x = 203 to X = 419 mm and was between the adhesive layer and 0° (ply 12, Table B2) ply and also between the 0° (ply 12, Table B2) and -45 ° (ply 11, 23) plies. The delamination also heavily affected the web, x = 260 mm to x = 356 mm, as the web delaminated fully between the interior -45° plies and also placed a spot delamination in the adhesive region on the tension flange. No shear stiffener, torsional stiffener or other tension flange damage or delaminations were visible. BEAM 10 Beam number 10 was fatigued at a rate of I Hz with a maximum load of 40.0 kN and a minimum load of 4.0 kN. The maximum load produced an initial maximum tension flange strain of 1.07 percent and a minimum compression flange strain o f-0.97 percent. The initial beam stiffness was measured as 3,694 kN/m. The initial hysteresis of the beam is shown in Figure B16 . As with Beam 9, the fiber waviness caused premature damage to be generated on the tension flange. The test was stopped after 1,870 cycles due to the amount of damage present on the tension flange and the white delaminated regions had reached both sides of the flange at x = 349 ± 13 mm. The beam stiffness was checked after the 1,870 cycles and equaled 3,384 kN/m, which was 92 percent of the initial stiffness. The failure site will probably occur at x = 254 ±12 mm due to the amount of accumulated damage in the 0° plies across the tension flange. No shear stiffener, torsional stiffener or compression flange damage or delaminations were visible at the end of the test. The failed beam is shown in Figure B17. 462 Tension flange - top view Side view 50 mm Figure B13. Beam 9. Compression flange Interior web delamination Figure B14. Beam 9. 463 -Ultimate Load = 59.2 kN -Tension Flange Max. Strain = 1.78% Compression Flange - Max. Strain = 1.80% - Absolute Maximum Flange Strain, % Figure B15. Load versus maximum flange strain beam 9, static test. z _ l % I I ' Q.Q. < I I I compression Hange-— __ t Z / Z V / ton Fitmge™ % Tens % S ' S ' 0.2 0.3 0.4 0.5 Absolute Maximum Flange Strain, % 0.6 Figure B16. Initial hysteresis of beam 10. 464 Tension side - top view Compression flange Side view 5 0 m m Figure B17. Beam 10. BEAM 11 Beam number 11 was fatigued at a rate of I Hz with a maximum load of 40.0 kN and a minimum load of 4.0 kN. The maximum load produced an initial maximum tensile flange strain of 1.08 percent and a minimum compressive flange strain of -0.96 percent. The initial beam stiffness was measured as 3,436 kN/m. The fatigue test was stopped after 3,100 cycles to check the stiffness of the beam. The stiffness had decreased to 3,061 kN/m which was 89 percent of the initial stiffness. Figure BI 8 shows the initial beam stiffness and the stiffness after 3,100 cycles. The fatigue test was resumed and the beam failed after 4,620 cycles with a tension flange failure. The maximum flange strain versus fatigue cycles is shown in Figure B19. The offset in the graph at 3,100 cycles is due to the unloading of the beam for the stiffness check. Prior to failure, numerous white damage nucleation sites were evident on the tension flange. Final failure of the flange occurred at x = 381 ± 17 mm and was very localized with some tearing of the top ±45° plies (ply I and 2, Table BI), which was noticed just prior to final failure. Delamination of the tensile flange occurred between the polyester matrix and the +45° ply (ply 13, Table BI) on the web flange with multiple amounts of fiber bridging and was located at x = 229 to x = 400 mm. Some delamination in the web was present and was caused by the flange failure. Figures B20 and B21 show the failed beam. No shear stiffener, torsional stiffener or compression flange damage or delaminations were visible. The load pads were manufactured as three separate plates that were then adhesively bonded together to get the required 12 mm load pad height. The upper most plate of this load pad assembly had partially delaminated in the adhesive interface from the rest of the pad. It is hypothesized that the adhesive layer was not thick enough to resist the applied compression loading on these pads. All four pads show the same partial delamination problem, but this did not influence the beam performance during the test. 465 Initial Stiffiiess Check Xx Stiffiiess Check ... a t 3,100 cycles I Tension Flange Failure at 4,620 Cycles 10 11 12 13 14 Tension Flange Midspan Deflection, mm Figure B18. Load versus flange midspan deflection, beam 11. 1.14 Tension Flangf Stiffiiess Check at 3,100 cycles E 1.08 I Compression Flange Tension Flange Failure at 4,620 Cycles Cycles Figure B19. Absolute maximum flange fatigue strain versus cycles, beam 11. 466 Tension flange - top view > Fatigue damage Figure B20. Beam 11. Figure B21. Beam 11. 467 Beam number 12 was fatigued at a rate of 2 Hz with a maximum load of 28.9 kN and a minimum load of 2.9 kN. The maximum load produced an initial maximum tension flange strain of 0.73 percent and a minimum compression flange strain of -0.68 percent. The initial beam stiffness was measured as 3,498 kN/m. As with the other beams, numerous white damage nucleation spots appeared on the tension flange during the fatigue test. These damaged areas grew and coalesced until the damage spanned across the flange. The final failure site started at one edge of the flange and grew to the other edge. After 30,290 cycles, the beam failed on the tension flange at x = 336 mm and is shown in Figure B22. The flange delaminated between the adhesive and the +45° ply (ply 12, Table BI) from x = 279 to x = 394 mm and contained multiple fiber bridging sites. The tension flange delamination traveled 45 mm into the web directly under the failure site. Some other minor cracks were evident on the flanges of the preform as the ±45 ° fabrics did not completely fill the C-channel mold, and thus created a matrix rich region on the flange edge, which cracked and segmented. These cracks were on the order of 10 mm in length, 5 mm wide and were located over the shear stiffener area of the beam. The load pads showed the same minor delamination problem as in Beam 11. Both these manufacturing flaws did not seem to cause any problems with the performance of the beam during the test. Otherwise, no shear stiffener, torsional stiffener or compression flange damage or delaminations were visible. BEAM 12 Tension flange - top view 12 Fatigue damage Figure B22. Beam 12. 468 Beam 13 involved a static test. The beam was loaded under actuator displacement control at a rate of 0.51 mm/s until failure, which involved a total ramp time of 21 seconds. An initial beam stiffness of 3,516 kN/m was measured. The ultimate load was 60.72 kN and corresponded to a maximum tension flange strain of 2.10 percent, a minimum compression strain of -1.85 percent and a maximum mid-span deflection of 17 mm. The load versus maximum strain graph is shown in Figure B23. The beam failed in the compression flange at x = 330 ± 25 mm with delaminations between the 0° (ply 10, Table BI) and +45 plies (ply 11, 22) over the distance of x = 165 mm to x = 457 mm. The failed beam is shown in Figures B24 and B25. The failure at x = 330 mm caused the web to delaminate towards the tension flange under this failure point, causing an additional delamination spot under the tension flange. No shear stiffener, torsional stiffener or other tension flange damage or delaminations were visible. BEAM 13 Compression Flange. -NAq v Q trQ iT i = I ^.Tension Flange Max. Strain = 2.10% Ultimate Load = 60.72 kN 0.2 0.4 0.6 0.8 I 1.2 1.4 1.6 Absolute Maximum Flange Strain, % Figure B23. Load versus maximum flange strain, beam 13, static test. 469 Compression flange - top view 50 mm Side view ----------- Figure B24. Beam 13. Figure B25. Beam 13. 470 BEAM 14 Beam number 14 was fatigued at a rate of 5 to 10 Hz with a maximum load of 24.5 kN and a minimum load of 2.5 kN. The maximum load produced an initial maximum tension flange strain of 0.59 percent and a minimum compression flange strain of -0.58 percent. The initial beam stiffness was measured as 3,407 kN/m. The fatigue test was stopped after 160,000 cycles to check the stiffness, which had reduced to 3,271 kN/m or 96 percent of the initial stiffness. After 389,175 cycles the tension flange failed at x = 248 ± 6 mm. The damage started at the edge of the tension flange and grew across the flange until final failure. The failure caused a delamination from x = 229 mm to x = 394 mm and was between the +45° ply (ply 16, 22) and the -45° ply (ply 17, Table BI) in the web flange. Figure B26 shows the failed beam. This delamination extended 10 mm down into the web. No shear stiffener, torsional stiffener or compressive flange damage or delaminations were visible. Tension flange - top view __— Delamination—___ Compression flange' s id e view 50 mm Figure B26. Beam 14. 471 BEAM 22 Beam number 22 was fatigued at a rate of 5 Hz with a maximum load of 31.1 RN and a minimum load of 3.1 RN. The maximum load produced an initial maximum tension flange strain of 0.84 percent and a minimum compression flange strain of -0.76 percent. The initial beam stiffness was measured as 3,637 RN/m. This beam had two acoustic emission sensors on the tension flange centered at x = 70 and 543 mm and two on the compression flange centered at x = 178 and 432 mm. The acoustic emission testing was performed with Dr. Al Beattie from Sandia National Laboratory and will not be discussed here. This beam showed less white damage sites on the tension flange than the previous beams during the fatigue test. Final failure occurred on the tension flange at x = 368 ±10 mm with a delamination between the +45° ply (ply 11, Table BI) and the -45° ply (ply 12, Table BI). The delamination was between x = 330 and 406 mm and grew 25 mm into the web. The failed beam is shown in Figure B27. No shear stiffener, torsional stiffener or compression flange damage or delaminations were visible. Tension flange - top view -------- Delamination i ^ / Compression flange' Side view 50 mm Figure B27. Beam 22. 472 BEAM 23 Beam number 23 was fatigued at a rate of 5 Hz with a maximum load of 28.9 kN and a minimum load of 2.9 kN. The maximum load produced an initial maximum tension flange strain of 0.71 percent and a minimum compression flange strain of -0.64 percent. The initial beam stiffness was measured as 3,542 kN/m. This beam also had two acoustic emission sensors on the tension flange centered at x = 64 and 543 mm and two on the compression flange centered at x = 178 and 438 mm. The beam failed in the tensile flange after 119,995 cycles. The failure site was at x = 318 ± 10 mm and created a delamination between the adhesive and the +45° ply (ply 13, 22) of the preform from x = 292 to x = 356 mm. This delamination extended 18 mm down into the web. The web flange had a matrix rich region on the edge of the flange between x = 279 and x = 470 mm and had a maximum depth towards the web of 8 mm. The failed beam is shown in Figure B28. The failure site of the tensile flange was within this matrix rich region and it is believed that the initial delamination did nucleate at this edge, between the adhesive and the preform. Although this beam went 89,705 cycles longer than Beam 12, it was assumed that this had some minor effect on the performance of the test, but not a large enough effect to be considered a structurally flawed beam. No shear stiffener, torsional stiffener or compression flange damage or delaminations were visible. Tension flange - top view Delamination 50 mm Figure B28. Beam 23. 473 Beams With Improved Flange and Web Materials Beams with DD5P Material Flanges and CHlO Web Material Beams 18 through 21 and 24 through 29 all had DD5P flange material, Vf = 0.36, consisting of a lay up of (07±4570°)s. The description of the I-beam flange layup and ply numbering scheme for these beams is outlined in Table B3. Table B3. Ply reference notation for Beams 18 - 21 and 24 - 29. Ply number Ply angle Fabric Description I 0 ° D155 DD5P flange material, 2.9 mm thick Vf = 0.36 2 +45° DB 120 3 -45° 4 0 ° D155 5 0 ° 6 -k LA O DB 120 7 +45° 8 0 ° D155 Adhesive Layer Hysol EA 9309.2NA, 0.1 - 0.4 mm thick 9 +45° DB240 Web material CHlO C-channel web flange 5 mm thick Vf = 0.35 10 -45° 11 +45° DB24012 -45° 13 +45° DB24014 LA O Flange, Ply I Ply 8 Web Flange jpfr j # I - Beam Web 474 Beam number 18 was fatigued at a rate of I Hz under sinusoidal load control with a maximum load of 62.3 kN and a minimum load of 6.3 kN. The maximum load produced an initial maximum tension flange strain of 1.42 percent and a minimum compression flange strain of -1.34 percent. The initial beam stiffness was measured as 4,134 kN/m. During the fatigue test, it was evident from the 0° fiber bundles delaminating from the flange surface that the DD5P flange material had been manufactured with a 2° to 3° angle. This angle caused the 0° edge terminated fibers to delaminate, starting from the flange edge and growing inward along the fiber bundle axis. This damage was confined to 4 to 6 mm from the flange edges and involved both the tension and compression flanges. The beam stiffness was checked throughout the test and is summarized in Table B4. As the fatigue test progressed, the tension flange started to delaminate from the C-channel between the 0° ply (ply 8 , Table B3) and the +45° ply (ply 7, Table B3). This initial delamination started in the center of the beam and was located directly above the tapered shear stiffeners, x = 165 mm and x = 457 mm. This delamination grew until the test was stopped after 9,367 cycles. At this point, the delamination extended from x = 127 mm to x = 571 mm, but had not completely traveled across the width of the flange. The compression flange had some transverse tensile cracks under the edges of the web and extended from x = 152 to 457 mm. There was also major flange damage at x = 381 to 432 mm, directly below the tapered shear stiffener, that was 18 mm wide. This damage involved broken 0 ° on the surface and delaminations throughout the thickness of the flange. The web had delaminations extending into the shear stiffeners, but otherwise the center web, x = 215 to x = 394 mm, had no other noticeable damage. One shear stiffener showed cracking at x = 444 ±12 mm on the tension flange side and was involved with the web delamination underneath. The failed beam is shown in Figure B29. Table B4. Beam 18 Stiffness versus Cycles. BEAM 18 Cycles Stiffness (K), kN/m Ratio (K/ 4,134) n /N N = 9,367 0 4,134 I — 1,000 3,714 0.90 0.11 2,000 3,619 0.88 0.21 3,000 3,632 0.88 0.32 4,000 3,659 0.88 0.43 5,000 3,486 0.84 0.53 6,000 3,509 0.85 0.64 8,000 3,428 0.83 0.85 9,367 3,150 0.76 I 475 Tension flange - top view Delamination Compression flange 50 mm Figure B29. Beam 18. BEAM 19 Beam 19 involved a static test. The beam was loaded under actuator displacement control at a rate of 0.05 mm/s until failure, which involved a total ramp time of 208 seconds and a total mid-span deflection of 13 mm. An initial beam stiffness of 4,245 kN/m was measured. As with the other static tests, the compression flange twisted prior to final failure. This twisting was also evident in the failed beam as one side of the beam flange had fragmented glass 0° and ±45° tows pointing up, while the other side of the flange had the fragmented glass tows pointing down. The compression flange failed at x = 305 ±15 mm with multiple delaminations throughout the flange thickness. The compression flange delaminated between the 0° ply (ply 5, 24) and -45° ply (ply 6 , Table B3) from x = 305 to 457 mm. The flange also delaminated between the 0° ply (ply 8 , Table B3) and the adhesive from x = 158 to 305 mm. The failure caused a delamination to travel into the web and created two spot delaminations on the tension flange in the adhesive layer. One shear stiffener showed some delamination at its tapered tip. No other shear stiffener, torsional stiffener or other tension flange damage or delaminations were visible. A maximum tension flange strain of 1.96 percent and a minimum compression flange strain of -1.82 percent, which occurred at a ultimate applied load of 89.2 kN, is shown in Figure B30. The failed beam is shown in Figure B31. BEAM 20 Beam number 20 was fatigued at a rate of 4 Hz under sinusoidal load control with a maximum load of 53.4 kN and a minimum load of 5.3 kN. The maximum load produced an initial maximum tension flange strain of 1.09 percent and a minimum compression 476 flange strain o f-1.09 percent. The initial beam stiffness was measured as 4,218 kN/m. The beam stiffness was checked throughout the test and is summarized in Table B5. The flanges of the beam showed the same 0° fiber misalignment, 2° to 3°, as in Beam number 18 and affected the edges of the flanges. The beam failed after 94,391 cycles due to the tension flange delaminating from the C-channel involving the 0° ply (ply 8, Table B3), the adhesive layer and the ±45° ply (ply 9, Table B3). This delamination was located between x = -75 to 521 mm. Along with the edge 0° fiber delamination, the compression flange also had transverse tension cracks from x = 178 to 445 mm on the flange located beneath the outside edge of the web. The web had delaminations extending 25 mm into the web towards the compression flange. The failed beam is shown in Figures B32 and B33. Ultimate Load = 89.18 kN ■Compression Flange Max. Strain = -1.82% Tension Flange Max. Strain = 1.96% 5 - 20 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0 Absolute Maximum Flange Strain, % Figure B30. Load versus maximum flange strain, beam 19, static test. 477 Compression flange 50 mm Figure B31. Beam 19. Table B5. Beam 20 Stiffness versus Cycles. Cycles Stiffness (K), kN/m Ratio (K /4,218) n /N N = 94,391 0 4,218 I — 2,000 4,133 0.98 0.02 10,000 4,009 0.95 0.11 30,000 3,726 0.88 0.32 50,000 3,522 0.83 0.53 73,000 3,022 0.72 0.77 90,000 2,978 0.71 0.95 478 Tension flange - top view Compression flange 50 mm Figure B32. Beam 20. Top of delaminated C - channel preform x = 215 mm x= 158 mm Cracked resin with friction marks ' Cracked and delaminated 45°tows Figure B33. Beam 20. BEAM 21 Beam number 21 was fatigued at a rate of 2 Hz under sinusoidal load control with a maximum load of 53.4 kN and a minimum load of 5.3 kN. The maximum load produced an initial maximum tension flange strain of 1.14 percent and a minimum compression 479 flange strain o f -0.99 percent. The initial beam stiffness was measured as 4,110 kN/m. The beam stiffness was checked throughout the test and is summarized in Table B6. This beam had a edge flaw on the tension flange edge at x = 400 ±5 mm and was I mm deep. This flaw was large enough to start flange delamination from the C-channel between the 0° ply (ply 8, Table B3) and the adhesive. After 23,000 cycles, the flange damage was 13 mm wide and extended from x = 342 mm to 440 mm. The delamination extended towards the web and 5 mm down into it. The compression flange had some transverse tension cracks centered about the web. No shear stiffener, torsional stiffener or other compression flange damage or delaminations were visible. The beam is shown in Figure B34. BEAM 24 Beam 24 involved a static test. The beam was loaded under actuator displacement control at a rate of 0.075 mm/s until failure, which involved a total ramp time of 190 seconds and a total mid-span deflection of 20 mm. An initial beam stiffness of 4,221 kN/m was measured. The beam had four acoustic emission sensors on the flanges: two on the tension flange centered at x = 76 and 549 mm, and two on the compression flange centered at x = 165 and 432 mm. A maximum tension flange strain of 1.93 percent and a minimum compression flange strain o f-1.77 percent that occurred at a ultimate applied load of 88.29 kN. As with the other static tests, the compression flange twisted prior to final failure. This twisting was also evident in the failed beam as both sides of the beam flange had fragmented glass 0° and ±45° tows pointing up. This was a different mode of buckling than the other beams had shown. The compression flange failed at x = 320 ±10 mm with multiple delaminations throughout the flange thickness. The compression flange delaminated between the O0 ply (ply 5, Table B3) and -45° ply (ply 6, Table B3) from x = 146 to 437 mm. The failure caused delaminations to travel through the web and into the tension flange adhesive layer. Transverse tension cracks were present on the tension flange from x = 250 to 458 mm. The failed beam is shown in Figure B35. No shear stiffener, torsional stiffener or other tension flange damage or delaminations were visible. Table B6. Beam 21 Stiffness versus Cycles. Cycles Stiffness (K), kN/m Ratio (K/ 4,110) n /N N = 23,000 0 4,110 I — 1,000 3,984 0.97 0.04 1,500 3,943 0.96 0.07 2,000 3,893 0.95 0.09 8,000 3,830 0.93 0.35 15,000 3,811 0.93 0.65 21,000 3,689 0.90 0.91 22,500 3,523 0.86 0.98 480 T ension f la n g e - to p view C om p re s s io n flan g e Figure B34. Beam 21. 50 mm Tension f lan g e - to p view D elam ination ^ C om p re ss io n flange 50 mm Figure B35. Beam 24. 481 Beam number 25 was fatigued at a rate of 2 Hz under sinusoidal load control with a maximum load of 62.3 kN and a minimum load of 6.2 kN. The maximum load produced an initial maximum tension flange strain of 1.43 percent and a minimum compression flange strain o f -1.13 percent. The initial beam stiffness was measured as 4,305 kN/m. The beam had four acoustic emission sensors on the flanges: two on the tension flange centered at x = 63 and 533 mm, and two on the compression flange centered at x = 170 and 430 mm. After 7,636 cycles, the compression flange failed at x = 229 ± 13 mm. A loud pop was heard one cycle prior to failure and it is suspected that a partial delamination grew to a point where it compromised the stability of the compression flange, lowering the strength of the beam to below the maximum fatigue stress. The final failure of the beam indicates a twisting of the compression flange at failure. The flange delamination extended from x = 170 to 432 mm and involved all the 0° to 45° interfaces and the adhesive layer. The delamination traveled into the web towards the tension flange and created two spot delaminations. Transverse tension cracks were also present on the tension flange over the web. It is not known if these transverse cracks were present prior to flange failure. No shear stiffener, torsional stiffener or other tension flange damage or delaminations were visible. The failed beam is shown in Figure B36. BEAM 25 C om D ress io n f l a n a e / ^ F a i l u r e Figure B36. Beam 25. 482 Beam number 26 was fatigued at a rate of 2 Hz under sinusoidal load control with a maximum load of 57.8 RN and a minimum load of 5.8 RN. The maximum load produced an initial maximum tension flange strain of 1.22 percent and a minimum compression flange strain o f -1.05 percent. The initial beam stiffness was measured as 4,355 RN/m. The beam stiffness was checRed throughout the test and is summarized in Table B7. After 104,407 cycles, the beam failed by compression flange delamination and shear stiffener failure. Shear failure of the compression flange occurred at x = 133 mm. This was under the compression flange load pad. The compression flange delaminated between the 0° ply (ply 8, 24) and the adhesive layer. Delamination of the tension flange above the shear stiffeners, x = 178 and 428 mm, was noticed at 10,000 cycles and continued to grow until failure. The beam is shown in Figure B37. All shear stiffeners showed some signs of delamination from the web. Table B7. Beam 26 Stiffness versus Cycles. BEAM 26 Cycles Stiffness (K), RN/m Ratio (K /4,355) n /N N= 104,407 0 4,355 I — 20,000 4,078 0.94 0.19 50,000 3,939 0.91 0.48 60,000 3,919 0.90 0.57 75,000 3,878 0.89 0.72 100,000 3,853 0.89 0.96 Tension flange - top view L ^ ' Compression flange 50 mm Figure B37. Beam 26. 483 Beam number 27 was fatigued at a rate of 3 Hz under sinusoidal load control with a maximum load of 53.4 kN and a minimum load of 5.3 kN. The maximum load produced an initial maximum tension flange strain of 1.07 percent and a minimum compression flange strain o f-1.00 percent. The initial beam stiffness was measured as 4,069 kN/m. As with the other DD5P beams, two tension flange delamination spots started over the tapered shear stiffener area, X= 178 and 445 mm. These spots grew during the fatigue test until the delamination was under a tension flange load pad. After 243,876 cycles, the tension flange delaminated. The delamination involved the adhesive layer and the adjacent 0° and 45° plies and was from x = -75 to 483 mm. Some transverse cracks were present on both the tensile and compression flanges prior to failure. The shear stiffeners under the delamination show some damage, but it is not known if this was present prior to failure. The web also has delaminations extending 15 mm down towards the compression flange. The failed beam is shown in Figure B38. BEAM 27 Tension flange T ra n sv e rse ten s io n c ra ck s C om p re ss io n flange Figure B38. Beam 27. 50 mm 484 Beam number 28 was fatigued at a rate of 5 to 12 Hz under sinusoidal load control with a maximum load of 44.5 kN and a minimum load of 4.4 kN. The maximum load produced an initial maximum tension flange strain of 0.86 percent and a minimum compression flange strain o f -0.85 percent. The initial beam stiffness was measured as 4,142 kN/m. Tension flange delamination spots started to develop over the tapered shear stiffener area, x = 178 and 445 mm, after approximately 600,000 cycles. After 2,000,000 cycles, the beam was stopped and the only damage present was the delamination between the tension flange and the adhesive layer. This is shown in Figure B39. The compression flange has two transverse tension cracks, x = 406 to 445 mm extending under the load pad. No shear stiffener, torsional stiffener or other flange damage or delaminations were visible. BEAM 28 Tension f lan g e - to p view Tension f lan g e ■ C om p re s s io n A an g ez 50 mm Figure B39. Beam 28. 485 Beam number 29 was fatigued at a rate of 4 Hz under sinusoidal load control with a maximum load of 48.9 RN and a minimum load of 4.9 RN. The maximum load produced an initial maximum tension flange strain of 0.92 percent and a minimum compression flange strain o f -0.96 percent. The initial beam stiffness was measured as 4,100 RN/m. Kapton film was placed between the strain gages and the flanges in hopes of preventing the matrix cracRs from traveling into the strain gages. The traveling was not stopped and the gages failed after 4,000 cycles. No significant improvement in strain gage lifetime, with the Kapton film, was observed. The beam was stopped after 815,684 cycles prior to beam failure. At this point the tension flange delamination extended between the 0° ply (ply 5, Table B3) and the -450 ply (ply 6, Table 4), x = 0to 115 mm, and between the adhesive and the 0°ply (ply 8, Table B3), x = 115 to 260 mm. The compression flange showed three small transverse tensile cracRs but otherwise no other damage. The beam is shown is Figure B40. BEAM 29 Tension flange - top view S tra in g a g e with K y n a r C om p re ss io n flange 50 mm Figure B40. Beam 29. 486 Beams with DD5P Material Flanges and CH3 Web Material Beams 30, 31, 32 and 33 had a stiffer web, CH3 versus CH10, to try to eliminate the tension flange from delaminating from the I-beam preform. The description of the I-beam flange lay up and ply numbering scheme for these beams is outlined in Table B8 below. Table B8. Ply reference notation for Beams 30, 31, 32 and 33. Ply number Ply angle Fabric Description I 0° D155 DD5P flange material, 2.9 mm thick Vf = 0.36 2 +45° DB 120 3 -k Ui O 4 0° D155 5 0° 6 -45° DB 120 7 +45° 8 0° D155 Adhesive Layer Hysol EA 9309.2NA, 0.1 - 0.4 mm thick 9 +45° DB240 Web material CH3 I-shape 3 mm thick Vf = 0.35 10 -45° 11 0° D155 12 +45° DB24013 -45° Flange, Ply I - - - t # ^ P I y 8 ___Ply 9 WebFlange Vx ^ I - Beam Web 487 Beam number 30 was fatigued at a rate of 2 Hz under sinusoidal load control with a maximum load of 62.3 RN and a minimum load of 6.2 RN. The maximum load produced an initial maximum tension flange strain of 1.20 percent and a minimum compression flange strain o f-1.05 percent. The initial beam stiffness was measured as 4,345 RN/m. The beam had four acoustic emission sensors on the flanges: two on the tension flange centered at x = 64 and 533 mm, and two on the compression flange centered at x = 178 and 432 mm. After 5,741 cycles, the test was stopped as the failure mode was identical to Beam number 26. The shear stiffeners had delaminated and the compression flange had a shear failure through its thicRness at x = 120 mm, under a compression flange load pad. The shear stiffener had a cracR at x = 120 mm, which was the start of the stiffener taper, 30 mm up towards the tension flange. The compression flange had a few transverse tension cracRs. The tension flange had started to delaminate over the shear stiffeners. No torsional stiffener or other tension flange damage or delaminations were visible. The failed beam is shown in Figures B41 and B42. BEAM 30 T en s io n f la n g e - to p view C om p re s s io n f la n g e 50 mm Figure B41. Beam 30. 488 Side view 50 mm Figure B42. Beam 30. BEAM 31 Beam number 31 was fatigued at a rate of 4 Hz under sinusoidal load control with a maximum load of 53.4 RN and a minimum load of 5.3 RN. The maximum load produced an initial maximum tension flange strain of 1.92 percent and a minimum compression flange strain o f -0.89 percent. The initial beam stiffness was measured as 4,764 RN/m. The stiffness was also checRed after a power outage at 796,633 cycles, 4,170 RN/m and after 2,030,240 cycles 3,248 RN/m. The test was stopped after 2,030,240 cycles. After these cycles 3 of the shear stiffeners had started to delaminate from the web and the tension flange had delaminated from the C-channel between x = 25 and 280 mm. There was also web delamination damage at x = 195 mm that extended down from the tension flange into the tapered shear stiffener area. The compression flange also had multiple transverse tension cracRs under this shear stiffener area. The beam is shown in Figure B43. Tension flange - top view Compression flange 50 mm Figure B43. Beam 31. 489 Beam number 32 was fatigued at a rate of 5 Hz under sinusoidal load control with a maximum load of 53.4 kN and a minimum load of 5.3 kN. The maximum load produced an initial maximum tension flange strain of 0.86 percent and a minimum compression flange strain o f-0.73 percent. The initial beam stiffness was measured as 4,639 kN/m. The beam stiffness was checked throughout the test and is summarized in Table B9. The fatigue test was stopped after 783,153 cycles. Like Beams 26 and 30, this beam started to have the same failure mode. The compression flange has sheared through the thickness at x =127 mm under a compression flange load pad at the edge of the torsional stiffener. The compression flange did not have any visible transverse tension cracks. The only other damage on the beam was the spot delaminations on the tension flange over the shear stiffeners. The beam is shown in Figure B44. Table B9 Beam 32 Stiffness versus Cycles. BEAM 32 Cycles Stiffness (K), kN/m Ratio (K /4,639) n /N N = 783,153 0 4,639 I — 5,000 4,231 0.91 0.01 10,000 4,149 0.89 0.01 15,000 4,161 0.90 0.02 20,000 4,180 0.90 0.03 65,000 3,863 0.83 0.08 75,000 3,844 0.83 0.10 85,000 3,869 0.83 0.11 250,000 3,823 0.82 0.32 Figure B44. Beam 32. 490 Beam number 33 was fatigued at a rate of 4 Hz under sinusoidal load control with a maximum load of 53.4 kN and a minimum load of 5.3 kN. The maximum load produced an initial maximum tension flange strain of 0.94 percent and a minimum compression flange strain o f-0.93 percent. The initial beam stiffness was measured as 4,606 kN/m. The beam stiffness was checked throughout the test and is summarized in Table BIO. The beam was stopped after 3,200,000 cycles. Although the beam had not failed, there was some tension flange delamination, three spots, which were growing and extended down into the C-channel at x = 318 mm. The compression flange had some minor transverse tension cracks. The beam is shown in Figure B45. Table B10. Beam 33 Stiffness versus Cycles. BEAM 33 Cycles Stiffness (K), kN/m Ratio (K/ 4,606) n /N N = 3,200,000 0 4,606 I — 200,000 4,184 0.91 0.06 300,000 4,215 0.92 0.09 500,000 4,150 0.90 0.16 3,200,000 3,873 0.84 I Figure B45. Beam 33. 4 9 1 Beams With DD5P Material Flanges With CH12 Material Webs Although the tension flanges were still delaminating from the web flange, Beams 34 and 35 had their fiber volume reduced to 0.34, CH12 material, with the same (±45o/0o/±45o)2 layup as the previous beams. This fiber volume showed promising fatigue response in standard coupon tests. Beam 34 Beam 34 involved a static test. The beam was loaded under actuator displacement control at a rate of 0.075 mm/s until failure, which involved a total ramp time of 65 seconds and a total mid-span deflection of approximately 8 mm. An initial beam stiffness of 4,990 kN/m was measured. The beam had two additional strain gages on the compression flange edges, both top and bottom of the flange. This was done to determine when the flange starts to buckle. The beam was loaded statically to 60 kN three times before the actual static test. The initial load - flange absolute maximum strain graph is shown in Figure B46 and shows the two standard strain gages on the center of the tension and compression flanges. Figure B47 shows the two compression flange edge gages, back-to- back, which indicates that the onset of buckling in this beam occurs at approximately 75 kN or 1.4 percent strain. The third load-up involved the static test and indicated a maximum tension flange strain of 1.92 percent and a minimum compression flange strain o f-1.69 percent that occurred at a ultimate applied load of 83.22 kN. The failure occurred on the compression flange at x = 292 ± 20 mm. The compression flange had transverse tension cracks and multiple delaminations between x = 150 and 457 mm. The delaminations extended through the web and into the adhesive layer on the tension flange, producing a delamination from x = 178 to 381 mm. The failed beam is shown in Figures B48 and B49. Figure B46. Absolute flange strain versus load, initial four point loading, beam 34. Ap pl ied F ou r P oin t L oa d, k l 492 Figure B47. Load versus compressive flange strain, beam 34. T e n s io n f l a n g e - to p v iew /D e l a m in a t i o n x S tr a in g a g e - ^ / / C o m p r e s s io n f la n g e 50 mm Figure B48. Beam 34. 493 Delamination' __50jT in i Figure B49. Beam 34. BEAM 35 Beam number 35 was fatigued at a rate of 2 Hz under sinusoidal load control with a maximum load of 62.3 RN and a minimum load of 6.3 RN. The maximum load produced an initial maximum tension flange strain of 1.04 percent and a minimum compression flange strain o f-1.02 percent. The initial beam stiffness was measured as 4,347 RN/m. The compression flange delaminated from x = -75 to 458 mm, after 9,771 cycles. The delamination of the flange caused the web to fail at x = 190 mm with delamination in the web from x = 178 to 267 mm. There were two spot delaminations on the tension flange, caused by the failure, at x = 190 to 356 mm. The failed beam is shown in Figures B50 and B51. T en s io n f la n g e - to p v iew D e lam in a tio n C o m p re s s io n f la n g e 5(3 m m Figure B50. Beam 35. 494 Figure B51. Beam 35. DD5P Material Flanges with DD5P Web Material Beams 51 through 55 were manufactured with both the flange and web consisting of DD5P material. This was done to increase the stiffness and fatigue response of the web. Beam 53 was tested first, which resulted in a shear stiffener failure. It was therefore necessary to increase the stiffener reinforcement under the load pads to handle the increased loads. The ply lay-up and numbering scheme is shown in Table BI I. BEAM 51 Beam number 51 was fatigued at a rate of 6 Hz under sinusoidal load control with a maximum load of 53.4 RN and a minimum load of 5.3 RN. The maximum load produced an initial maximum tension flange strain of 0.76 percent and a minimum compression flange strain o f -0.75 percent. The initial beam stiffness was measured as 4,867 RN/m. The beam was stopped after 3,000,000 cycles with no significant change in stiffness and no major damage. Figure B52 shows the only noticeable damage on the beam, transverse tension cracRs on the compression flange. Figure B53 shows the additional shear stiffener material that was added to the beam. BEAM 52 Beam number 52 was fatigued at a rate of 3 Hz under sinusoidal load control with a maximum load of 62.3 RN and a minimum load of 6.2 RN. The maximum load produced an initial maximum tension flange strain of 0.93 percent and a minimum compression flange strain o f -0.89 percent. The initial beam stiffness was measured as 5,145 RN/m. Initially the compression flange showed no evidence of bucRling, but after 16,000 cycles, it was noticed that the compression flange had a small localized bucRling node at x = 395 mm that was present on only one flange edge. This node, or area of increased localized displacement, did not change until the failure of the beam after 62,843 cycles. The 495 compression flange failed at x = 395 mm, the node, with multiple delaminations in the preform and flange. The compression flange delaminations extended from x = 200 to 460 mm and were between the 0°ply and adjacent 45° plies throughout the flange and preform thickness. This delamination also traveled into the web. The failed beam is shown in Figure B54. Table BH . Ply reference notation for Beams 51 through 55. Ply Number Ply Angle Fabric Description I 0° D155 DD5P flange material, 2.9 mm thick Vf = 0.36 2 +45° DB 120 3 -45° 4 0° D155 5 0° 6 -45° DB 120 7 +45° 8 0° D155 Adhesive Layer Hysol EA 9309.2NA, 0.1 - 0.4 mm thick 9 0° D155 DD5P web material I-shape 3 mm thick Vf = 0.36 10 +45° DB240 11 -45° 12 0° D155 Ply I Ply 8 Adhesive layer 496 C o m p r e s s io n f la n g e Figure B52. Beam 51. Figure B53. Additional shear stiffener material. C om p re ss io n flange 50 mm Figure B54. Beam 52. 497 Beam number 53 was fatigued at a rate of 3 Hz under sinusoidal load control with a maximum load of 62.3 kN and a minimum load of 6.2 kN. The maximum load produced an initial maximum tension flange strain of 0.94 percent and a minimum compression flange strain o f -0.89 percent. The initial beam stiffness was measured as 4,901 kN/m. The beam was stopped after 8,700 cycles due to a shear stiffener and web failure inside the shear loading area of the load pads. This damage is shown in Figure B55. Due to this failure, additional stiffener material was added to the other beams (51,52 and 54) tested at this or higher loads. BEAM 53 Compression flange /Load pad Figure B55. Beam 53. 498 Beam number 54 was fatigued at a rate of 4 Hz under sinusoidal load control with a maximum load of 62.3 kN and a minimum load of 6.2 kN. The maximum load produced an initial maximum tension flange strain of 0.88 percent and a minimum compression flange strain o f-0.88 percent. The initial beam stiffness was measured as 4,951 kN/m. The compression flange showed no evidence of buckling throughout the test. The beam failed after 2,744,704 cycles with a web and shear stiffener failure shown in Figure B56. BEAM 54 Figure B56. Beam 54. 499 BEAMS WITH STRUCTURAL DETAILS Beams With Holes In AA Material (Triax) Flanges To study the effects of severe flaws in flanges, 13 mm diameter holes were drilled on 102 mm centers along the length of each flange, through the flange thickness. This geometry, shown in Figure B57, included two holes on the compression flange and four holes on the tension flange. The holes were drilled into the flanges prior to the adhesive bonding to the preform. This was done to ensure that no damage was initiated in the web. Therefore, the flange hole penetrated the flange thickness, but stopped at the adhesive layer above the web flange. The tension flange had four-13 mm diameter holes located at x = 152, 254, 365 and 457 mm on the center line of the flange (y = 0). The compression flange had two -13 mm diameter holes at x = 254 and 356 mm. The web was CHlO Material, as in the foregoing series. x = 6 1 0 mmx = 3 5 6 mmLoad p ad x = 152 mm T ension f la n g e x = 4 5 8 mmx = 254 mmx = 0 mm 13 mm diameter holes x = 2 52 mm x = 3 56 mm C om p re s s io n f la n g e S id e v iew Figure B57. Beams 15,16 and 17 flange geometry. 500 Beam number 15 was fatigued at a rate of I Hz under sinusoidal load control with a maximum load of 31.1 kN and a minimum load of 3.1 kN. The maximum load produced an initial maximum tension flange strain of 0.83 percent and a minimum compression flange strain of -0.78 percent, both measured between hole locations. The initial beam stiffness was measured as 3,260 kN/m. The stiffness was checked after 2,163 cycles and was 3,064 kN/m or 94 percent of the original stiffness. The tension flange had two strain gages: one in the center of the flange and another at the edge. During the initial load up, at 18 kN, the center gage indicated 0.419 percent strain, while the edge gage was 0.429 percent, which is no significant difference. During the fatigue test, damage started to develop at all the holes and grew until it reached the edge of the flange. The beam failed after 2,772 cycles, in compression with the compression damage at x = 254 mm. Multiple delaminations between the 0° and +45° plies from x = 229 to x = 286 mm were also present. The compression flange failure and delamination caused an additional delamination to travel into the web at x = 244 to x = 279 mm. The failed beam is shown in Figure B58. No shear stiffener, torsional stiffener damage or delaminations were visible. BEAM 15 Tension flange - top view Figure B58. Beam 15. 501 Beam number 16 was fatigued at a rate of 5 Hz under sinusoidal load control with a maximum load of 24.5 kN and a minimum load of 2.5 RN. The maximum load produced an initial maximum tension flange strain of 0.58 percent and a minimum compression flange strain o f -0.53 percent. The initial beam stiffness was measured as 3,340 kN/m. During the fatigue test, damage started at the outside edges of the holes and continued to grow until failure after 40,448 cycles. The beam failed on the tension flange at x = 356 ± 13 mm with the underlying delamination between x = 325 to x = 394 mm. This delamination also traveled 25 mm down into the web. Prior to failure, the web had a large number of 1.0 to 1.5 mm long tensile cracks, all located at stitching cross over points. Although these small cracks probably did not have any influence on the failure, it is still disconcerting that every stitch cross-over point on the tension side of the neutral axis had a crack. Some minor delamination damage was present on the tension flange around the holes. No shear stiffener, torsional stiffener damage or delaminations were visible. The failed beam is shown in Figures B59 and B60. BEAM 16 Tension flange - top view Compression flange Figure B59. Beam 16. 50 mm 502 Tension flange - top view Damage initiation Strain gage ^Failure Figure B60. Beam 16. BEAM 17 Beam 17 was tested statically to failure. The beam was loaded under actuator displacement control at a rate of 0.05 mm/s until failure, which had a total ramp time of 196 seconds. An initial beam stiffness of 3,350 kN/m was measured. The beam had a total of six strain gages, with three on the tension flange and three on the compression flange. At 18 kN, the tension flange indicated a center strain of 0.33 percent while the two edge gages indicated 0.42 percent and 0.42 percent. The compression flange center gage indicated -0.37 percent and the two edge gages indicated -0.39 percent and -0.37 percent. The difference in strain from the center, where the flange is discontinuous, and the edge is more pronounced than the strains recorded from Beam 15. As the beam was loaded, the compression flange did not appear to twist as in the other beam static tests. The load- flange absolute maximum strain graph is shown in Figure B61, indicating a maximum tension flange center strain of 1.30 percent and a minimum compression flange center strain o f -1.08 percent. These strains occurred at a ultimate applied load of 47.0 kN at a maximum mid-span deflection of 15 mm. The failed beam is shown in Figure B62. The compression flange failed at x = 260 ±15 mm and created a flange delamination from x = 178 to x = 419 mm. The delamination was between the 0° ply (ply 10, Table BI) and +45° ply (ply 11, Table BI). This delamination traveled up towards the tension flange and produced a spot delamination at the tension flange hole. The second hole on the compression flange had a 12 mm delamination going towards the edge, but the damage at the other hole produced the flange failure first. 503 50 g 40 d 3 0 £ 2 0 Q . Q . < 10 0 0 0 . 2 0 . 4 0 . 6 0 . 8 1 1 . 2 1 . 4 A bso lu te M aximum F lang e S tra in , % Figure B61. Load versus maximum flange strain, beam 17, static test. U lt m a te ] ,o ad = 4 6 .9 7 kN com p re ss io n r iange M ax. S tra in = 1 .0 8% Z y Z ' T ension lax . Sti Flange rain = .3 0% y Z Tension flange - top view Figure B62. Beam 17. 504 DD27 Material Flanges Cwith balsa wood) and CH12 Web Material Beams 58 and 59 involved 6 mm thick balsa wood, Baltek AL600, in the DD5P flange material to simulate actual wind turbine lay-up configurations. The ply lay-up and numbering scheme is listed in Table B12. The balsa wood core was replaced with ±45° ply DB400 under the load pads to prevent crushing damage. BEAM 58 Beam number 58 was fatigued at a rate of I Hz under sinusoidal load control with a maximum load of 62.3 kN and a minimum load of 6.2 kN. The maximum load produced an initial maximum tension flange strain of 0.97% and a minimum compression flange strain o f-1.00%. The initial beam stiffness was measured as 5,341 kN/m. The compression flange failed after 230 cycles. The fiberglass plies delaminated from the balsa wood from x = 160 to 410 mm. This was a buckling induced compression flange failure. It is a possibility that the load pad / balsa wood core drop area influenced the failure. The failed beam is shown in Figure B63. BEAM 59 Beam number 59 was initially fatigued at a rate of 4 Hz under sinusoidal load control with a maximum load of 35.6 kN and a minimum load of 3.6 kN. The maximum load produced an initial maximum tension flange strain of 0.58% and a minimum compression flange strain o f -0.59%. The initial beam stiffness was measured as 5,512 kN/m. The beam was stopped after 1,000,000 cycles with no major noticeable damage. At this point the fatigue load was increased to a maximum load of 44.5 kN/m and a minimum load of 4.4 kN/m. This resulted in a maximum strain of 0.75% and a minimum strain o f-0.75%. The compression flange failed after 88,993 cycles. The compression flange appeared to be sheared off at the edge of the load pad, which then delaminated from the balsa wood core from x = 160 to 350 mm. The delamination traveled into the web and produced two spot delaminations on the tension flange. The failed beam is shown in Figure B64. 505 Table B12. Ply reference notation for Beams 58 and 59. Ply number Ply angle Fabric Description I 0° D155 2 +45° DB 120 3 -k LA O 4 0° D155 6 mm balsa wood core 5 0° D155 6 Om DB 120 7 +45° 8 0° D155 Adhesive layer Hysol EA 9309.2NA, 0.1 - 0.4 mm thick 9 +45° DB240 Material CH12 I-shape 5 mm thick Vf = 0.37 10 -45° 11 0° D155 12 O DB240 13 +45° Flange ■■i / / P i y i Ply 8 — Adhesive layer 506 Figure B67. Beam 58 C om p re s s io n f la n g e C om p re s s io n f la n g e Failu re 50 mm Figure B68. Beam 59 MONTANA STATE BOZEMAN