Long-Term Durability Prediction for FRP Composite Materials

KaZaK proposes to continue the development, application, and verification of a durability prediction methodology for FRP composites, including the combined effects of temperature, moisture, and other environmental factors, such as exposure to an alkaline environment. The methodology exploits the use of a well-established physical principle of polymer material behavior in conjunction with a new three-dimensional failure theory. This failure theory directly incorporates the mechanical properties of the fiber and matrix through a micromechanical analysis of their interaction. Four different critical material parameters are required for its application. The methodology is based on a set of re-usable “master curves” to predict the durability of arbitrary laminates and structures under a range of environmental conditions. Master curves of static strength and fatigue life are obtained from a limited set of creep and fatigue tests on simple unidirectional coupons. The application of the master curves to arbitrary laminates and strain states is accomplished through the failure theory. Phase II efforts will include (1) extending the durability methodology to include environmental degradation factors of specific importance to infrastructure applications of FRP composites; (2) completing a significant test matrix; (3) demonstrating predictive capability by comparison to test results; and (4) developing software tools for commercialization.