Damage and fatigue life prediction of short fiber reinforced composites submitted to variable temperature loading: Application to Sheet Molding Compound composites

The majority of fatigue life prediction models which have been proposed for the Short Fiber Reinforced Composite (SFRC) materials have been developed for constant temperature. However, in real situations, SFRC structures are subjected to variable temperature. This study focus on the response of SFRC composites subjected to different sequences (or blocks) under variable temperature conditions. Experientially, this kind of study requires a lot of investment from the point of view of cost and time. In this paper, the results coming from modelling the fatigue life and residual stiffness of short fiber reinforced composites subjected to thermomechanical loadings are reported. In fact, we propose to use a hybrid micromechanical-phenomenological model to quantify the evolution of the local damage rate during each loading block. Indeed, damage accumulation is calculated and cumulated step by step through the calculation of the evolution of a local damage ratio which describes the evolution of micro-cracks density until failure. Life prediction for specimens submitted to a variable temperature loading found to give acceptable results compared to experiments.