Failure mechanism of thermo-mechanical coupling of 3D braided composites with different thickness under high strain-rate punch shear loading

This work reports the thermo-mechanical response of rectangular carbon fiber/epoxy resin three-dimensional (3D) braided composites under high strain-rate punch shear loading. 3D braided composites with thickness of 3 mm, 5 mm and 8 mm were investigated under high strain-rate of 1500 s-1 and 2000 s-1. A thermo-mechanical coupling full-scale finite element model was established to acquire the distribution of transient heat and stress on different paths. The failure modes of composites were sensitive to thickness and strain-rate. The results showed that transient heat was mainly generated in resin during adiabatic shearing, and the accumulation of heat accelerated the destruction of the shear band. By analyzing the distribution of transient heat and stress, the damage morphology and complex failure mechanism of 3D braided composites under high strain-rate punch shear loading were revealed.