Life prediction of PPS composites subjected to cyclic loading at elevated temperatures

Combinations of failure mechanisms are frequently encountered in the Life p rediction of composite materials. A Life prediction methodology is develope d and applied to one such failure mechanism combination. This method uses e xperimental data and analytical tools to predict the long-term behavior of a composite under service conditions. The,prediction scheme is based on the assumption that damage accumulation progressively reduces the remaining st rength of a composite. An overview of the fundamental concepts of the Life prediction method is presented. The method is used to model the elevated te mperature fatigue behavior of a unidirectional AS-4 carbon fiber/PolyPhenyl ene Sulfide (PPS) matrix composite material. The nonlinear combined effects of time at elevated temperature and fatigue are taken into account by cons idering elevated temperature tensile rupture and room temperature fatigue b ehavior. The life prediction for the combined loading is compared to 90 deg rees C tensile-tensile fatigue data. This comparison shows good correlation between the prediction and data and demonstrates the method's effectivenes s in Life prediction modeling.