Long-Term Durability Prediction for FRP Composite Materials

KaZaK proposes to investigate the feasibility of extending a recently-developed methodology for CFRP and GFRP static strength, creep and fatigue life predictions to include the combined effects of temperature, moisture, and other environmental factors. The methodology exploits the use of a well-established physical principle of polymer material behavior in conjunction with a new and rational failure theory. The failure theory incorporates the mechanical properties of the fiber and matrix, as well as the micromechanics of their interaction. Four different failure parameters are required for its implementation. Material parameters are obtained from an accelerated set of creep and fatigue tests on simple uni-ply coupons. The number of required coupons is greatly reduced as compared to aerospace design practices. The methodology yields a set of re-usable “master curves” to predict the durability of arbitrary laminates and structures under a range of environmental conditions. Phase I efforts will involve (1) extension of the durability methodology to include degradation behavior and environmental conditions of importance to the Army; (2) establishing the test matrix for an extensive Phase II laboratory and field verification; (3) establishing the requirements for a software tool that implements the methodology; and (4) developing a commercialization plan for the software.