Finite element model for simulating entropy-based strength-degradation of carbon-fiber-reinforced plastics subjected to cyclic loadings

In this study, a novel model for simulating strength and fracture energy reductions based on the stress and strain histories of a carbon-fiber-reinforced plastic (CFRP) ply is developed, thus allowing us to comprehensively simulate the versatile failures including fatigue failure for CFRPs. The strength and fracture energy reductions are defined as functions of entropy generation. The entropy value is obtained from the absolute temperature and dissipated mechanical energy, such as the area of the inelastic hysteresis loop. Strength and fracture energy reductions are introduced into the conventional Hashin's criterion. An algorithm for this model and some numerical validations are presented herein. Through a simplified CFRP laminate model with frequency dependence, a delayed failure of 90 degrees layer under cyclic displacement conditions is numerically simulated.

Automated summary

In this study, a novel model is developed to simulate the reductions in strength and fracture energy for carbon-fiber-reinforced plastic (CFRP) plies, allowing for comprehensive simulation of various failures. The model defines reductions in strength and fracture energy as functions of entropy generation, and incorporates them into the conventional Hashin's criterion for validation.