A stiffness degradation model for composite laminates under fatigue loading

Abstract An investigation has been conducted for the purpose of evaluating the stiffness degradation of composite laminates during fatigue loading. Based on this investigation, a model is proposed that is capable of predicting the stiffness degradation in composite laminates. This model is based on an assumed relationship between the failure stiffness and the applied stress. An experimental program comprised of a number of static and fatigue tests using coupon specimens of graphite/epoxy [±35] 2S laminates was carried out for the purpose of evaluating the model.