A new phenomenological creep residual strength model for the life prediction of the laminated composites

Abstract

AbstractFiber‐reinforced plastics have extensive applications in advanced industries in which the material is subjected to long time sustained loadings that stimulates time‐dependent damage development in laminated composites. In the present article, a new phenomenological residual strength model is proposed for unidirectional composites under sustained loading. A normalization technique is suggested, which accumulates the spread residual strength data, and a power‐law model is developed to describe the normalized residual strength data under arbitrary states of stress and sustained times. Accelerated creep experiments were performed on T300/L20 carbon/epoxy unidirectional laminates. The residual strength data of tested T300/L20 unidirectional laminates and available data in the literature for Kevlar/epoxy and S‐glass/epoxy strands are used to examine the model predictions. It is shown that the presented normalization procedure is an effective way for modeling the residual strength of unidirectional composites, and the model can discriminate the rate of damage growth under various stress states.