Modeling of Short Fiber Reinforced Polymer Composites Subjected to Multi‐block Loading

Abstract

Short Fiber Reinforced Composite (SFRC) structures exhibit multiple microstructures (due to material flow during the process). They are generally subjected to variable amplitude loadings. In this context, a robust model is needed to predict fatigue life as a function of microstructure. In this paper, we propose a predictive micromechanical damage-based model allowing fatigue life prediction in the case of SFRC submitted to variable amplitude cyclic loading. An experimental study was firstly performed on Sheet Molding Compound (SMC) composite involving different microstructure configurations. Specimens were subjected to stress-controlled block loading. The influence of the order of the sequences was evaluated through Low-High amplitude (L-H) and High-Low amplitude (H-L) schemes. Damage accumulation is computed at the local scale to describe the evolution of the fiber-matrix interface damage until failure. A local failure criterion based on a critical damage state allowed predicting variable amplitude fatigue life as a function of microstructure. A good correlation was found between experimental and numerical results. Once the approach was validated, it has been used to model different useful variable amplitude loading schemes to emphasize the role of the loading sequence parameters and order.