Browsing by Author "Wilson, Timothy James"

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Modeling of in-plane and interlaminar fatigue behavior of glass and carbon fiber composite materials
(Montana State University - Bozeman, College of Engineering, 2007) Wilson, Timothy James; Chairperson, Graduate Committee: Douglas S. Cairns
This thesis presents the results of a modeling study of the fatigue behavior of fiberglass and carbon fiber reinforced epoxy composite materials intended primarily for wind turbine blades. The modeling effort is based on recent experimental results for infused glass fiber laminates typical of current blades, and hybrid carbon prepreg laminates of potential interest for future blades. There are two focus areas: in-plane performance represented by stress-life (S-N) curves, and out-of-plane ply delamination at details including ply drops and joints, based on fracture mechanics. In-plane fatigue models for both the mean performance and a statistically fit model with a 95/95 confidence limit were developed for three laminates, each representative of lower cost materials with applications in the wind turbine industry. These include polyester and epoxy resin infused glass fabrics and a hybrid carbon prepreg; two of the materials were tested in the axial and transverse directions. Models were adapted for the S-N results at several uniaxial loading conditions, including special treatment of the time dependence at high loads.