Scholarship & Research
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Item Full scale component level testing & severity analysis of phantom 3 UAV to Cessna 182b aircraft collisions(Montana State University - Bozeman, College of Engineering, 2021) Hayes, Benjamin Woodruff; Chairperson, Graduate Committee: Robb LarsonUnmanned Aircraft Systems (UAS) are more attainable now than ever before. With uses ranging from re-forestation, agriculture, film-making, and recreation; a significant amount of airspace is being occupied by UAS. To better understand the risks posed by UAS to other aircraft, the Alliance for System Safety of UAS through Research Excellence (ASSURE) was created. One aspect of ASSURE's agenda is to conduct air to air collision studies using Finite Element Analysis (FEA) in combination with full scale collision data. Montana State University contracted with ASSURE to conduct component level testing for the project, and provide data for validating FEA models being developed at the National Institute of Aviation Research (NIAR). Component level testing consisted of the following aircraft components: Cessna 182B struts, wings, and windscreens. In order to accurately simulate in-flight geometry, fixtures were custom fabricated to individually mount aircraft components. High velocity impact data was collected via load cells, high speed video, and Digital Image Correlation (DIC). A drone launching system developed during an MSU conducted research effort was used to launch Phantom 3 quadcopter UAVs as projectiles for component level tests. For all tests, the impact was captured from two viewpoints using high speed video, and reaction force data was collected using load cells at critical attachment points. For wing and windscreen testing, 2-D DIC and 3-D DIC were used respectively to capture displacements during the collision. Testing showed that struts received mainly superficial damage, but that both wings and windscreens exhibited the potential for catastrophic failure.Item Cessna 182b windscreen material model development and full scale UAS to aircraft impact testing facility(Montana State University - Bozeman, College of Engineering, 2020) Arnold, Forrest Jacob; Chairperson, Graduate Committee: Douglas S. CairnsUnmanned Aircraft Systems (UAS) have become popular in the last decade. More than 1.5 million have been registered by the Federal Aviation Administration (FAA) since 2015. In order to understand the risk UAS pose to manned aircraft and make informed regulation decisions, the FAA has created air to air collision studies. As a part of the FAA general aviation air to air collision research, a Cessna 182 windscreen material model and a full scale impact testing facility were required. A Finite Element Crash Model of a Cessna 182 is in development as a part of the general aviation air to air collision research. The National Institute for Aviation Research at Wichita State University is managing development of the model. In support of that work, an LS-DYNA material model of the Poly(Methyl methacrylate) windscreen was developed. Results from tensile testing at multiple strain rates were used to develop material models using MAT_124 and MAT_187. A model of an impact tower was created to compare the material models to test results. The material models were tuned to better fit the impact tower test results. MAT_187 has more flexible material inputs, which allowed it to outperform MAT_124. A full scale impact testing facility was developed to support Finite Element model validation and direct testing of UAS to aircraft impact. A slingshot style launcher was designed and built to launch common quadcopter style UAS. Testing has shown that the launcher is capable of 120 knots with the accuracy required to repeatably hit the leading edge of a wing. Additionally, the launch site required a system for instrumented testing to compare experimental results with finite element results. A system was developed to allow flexible fixturing, impact speed and orientation measurement, and inclusion of load cells and strain gauges.Item Developing a load acquisition system for a multiaxial test frame(Montana State University - Bozeman, College of Engineering, 2019) Carpenter, Aaron James; Chairperson, Graduate Committee: David A. MillerMaterial testing has traditionally been completed by using a uniaxial load frame which isolates a single stress component. Engineers however, design components for applications in a multi-axial world to withstand stress in multiple directions. The In-Plane Loader (IPL) at Montana State University expands the realm of material testing to three degrees of freedom within a two-dimensional plane. Applications of the IPL include composite material testing and experimental validation of constitutive models in multiple axes. The multi-axial test frame has been in place at MSU for several years. One of the primary challenges associated with the IPL is its ability to accurately measure multi-axial load components. The purpose of this work was to develop and validate an updated multi-axial load acquisition system for the IPL. The procedure included design, manufacture, implementation, and validation of the system. Validating the system in multiple axes required isolating single stress components along each of the planar axes. Tension tests were completed to isolate the vertical component, and shear tests were completed to isolate the horizontal component. Each of the results were compared to results of standardized test procedures designed to isolate their respective stress components. Digital image correlation was implemented as a non-contact method of measuring displacement for the testing procedures. The data collected in this study provides confidence in the ability to measure multi-axial loading in combination with digital image correlation to expand the capabilities of multi-axial testing. The system provides the ability to study load dependent failure of materials as well as displacement dependent failure. The information presented provides an understanding of challenges associated with multi-axial testing which hopes to assist in the development of future multi-axial test frames.Item An acoustic emission and hygrothermal aging study of fiber reinforced polymer composites(Montana State University - Bozeman, College of Engineering, 2019) Newhouse, Kai Jeffrey; Chairperson, Graduate Committee: David A. MillerFiber reinforced polymer matrix composites are a premier choice for offshore wind turbines and Marine Hydro-Kinetic Devices, which operate in harsh and isolated marine environments. These factors combined with decades long target service life make imperative the understanding of damage mechanisms and the environmental effects thereof. Acoustic emission monitoring is a research technology that uses specialized sensors to detect transient elastic waves in a material which originate from damage sources. Waveform parameters have been correlated with different damage mechanisms in fibrous composites. A diverse set of fiber-matrix combinations configured into a variety of layups totaling more than 30 laminates were mechanically tested in quasi-static uniaxial tension while monitoring acoustic emission. A subset of these materials was aged prior to testing in an artificial marine environment by soaking in a water bath of simulated seawater at 50 degrees Celsius. Various acoustic emission waveform parameters were investigated with respect to expected damage between layups and possible material-based differences. Among the conditioned material set, mechanical changes from moisture absorption shows mixed levels of degradation among different material systems. Moduli were generally unaffected with a few minor decreases. Strengths were reduced by as much as 41%, and failure strains fell as much as 47%. From acoustic emission investigation, good correlation is found between Fast Fourier Transform peak spectral frequency bands and expected damage mechanisms between layups. Material based peak frequency differences are found exclusively in interphase failures (de-bond and fiber pullout). Layup-based correlations in conjunction with elastic wave theory were used to put forth new frequency band ranges associated with damage types.Item Damage characterization of fiber reinforced composite materials by means of multiaxial testing and digital image correlation(Montana State University - Bozeman, College of Engineering, 2017) Jette, Joseph Terrance; Chairperson, Graduate Committee: Douglas S. CairnsComposite materials offer a unique quality to improve structural designs. Now, not only can a structure's geometry be designed, composite materials offer the engineer the ability to design the layup of the material and, in turn, control some of its structural properties. While this feature of composite materials is appealing, it also poses issues for all processes involved in its design. One of the primary issues is that characterization of these materials in different orientations is often difficult and expensive. Due to composite materials' anisotropy, heterogeneity, and variability, their constitutive and damage behavior remain poorly understood. Often due to this misunderstanding, designs that use composite materials undergo a lengthy, difficult, and expensive procedures to produce the final product. Part of these procedures is the finite element modeling and simulation of designed components which requires accurate material response data. As modeling capabilities improve, provided the proper material damage response modeling data, damage models offer the ability to predict the damage response of designs. The ability to accurately predict damage responses in structures is a primary contributor to a design's development time and its overall success. In this study, multiaxial testing via the Montana State University In-Plane Loader was performed on two carbon fiber epoxy prepreg material systems. This testing was performed to determine the usefulness of digital image correlation and multiaxial testing as a means of characterizing composite materials' damage responses and to produce data capable of informing and validating damage models. The combination of digital image correlation and multiaxial testing provided dense experimental results that may prove useful to qualitatively and quantitatively inform, validate, and enhance computer finite element modeling and analysis.Item Exploring the effects of fiber angle and stacking sequence on the static strength and acoustic emission signature of epoxy-fiberglass composites in marine environments(Montana State University - Bozeman, College of Engineering, 2017) Nunemaker, Jake Douglas; Chairperson, Graduate Committee: David A. MillerMarine Hydro-Kinetic (MHK) devices encompass promising new technologies designed to harness energy from ocean currents and tides. However, there are unique challenges to successful implementation of MHK devices. Material selection and characterization are crucial steps in the design process as the marine environment can be extremely detrimental to many materials systems. Epoxy-fiberglass composites, the premier material in wind turbine blades are being studied for use in MHK due to desirable price and durability. Preliminary research has shown a significant drop in ultimate strength due to moisture absorption in unidirectional laminates. This research extends these studies by exploring these effects on balanced and unbalanced off-axis fiber angles for a common epoxy-fiberglass material system. Ply by ply analysis is completed to explore the efficacy of a strength reduction prediction method for off-axis laminates. It also extends the study to include acoustic emission analysis to further investigate the material degradation at a micromechanical level. Partial saturation strength reduction in symmetric laminates is also studied.Item Resistivity and heat transfer characteristics of high temperature film anemometers(Montana State University - Bozeman, College of Engineering, 1990) Anders, Scott GeraldItem Tensile testing of metal/metal and ceramic/metal brazed joints(Montana State University - Bozeman, College of Engineering, 1991) Shreeram, RajItem A more complete and inexpensive gasoline engine test procedure(Montana State University - Bozeman, College of Engineering, 1964) Whitehill, Cassius FurmanItem Application of energy methods to modeling failures in composite materials and structures(Montana State University - Bozeman, College of Engineering, 2004) Ritter, William Joseph; Chairperson, Graduate Committee: Douglas S. CairnsCharacterizing the mechanical properties of composite materials is difficult and expensive. There is a legacy for the scale up from basic materials testing to final structures in composites. Each material architecture and manufacturing technique potentially represents a different mechanical response in a structure. Hence, as new composite material forms and manufacturing techniques become available, a need exists to streamline the characterization process. In this study, a new methodology for characterization of composite materials and structures is presented. It has its roots in fracture mechanics, but has been extended to the complexities of composite materials. The methodology is provided along with sample applications. While preliminary, the methodology has the potential for providing a meaningful scaling procedure for the materials / manufacturing / structural performance links for composite materials and structures.