Microstructure modeling multiple transverse impact damages of 3-D braided composite based on thermo-mechanical coupling approach

Abstract

A microstructure model based on fully thermo-mechanical coupling behavior of 3-D braided composites has been proposed for characterizing multiple transverse impact damage. The interfacial contact and cohesive debonding, as well as ductile and shear damage, incorporate with thermo-mechanical coupling constitutive equations have been employed in the model. It was shown that the adiabatic temperature rise and interfacial damage are concentrated on the impact surface with local plastic deformation. The heat energy generated in impact interaction caused local temperature rise, which further leads to thermal expansion of epoxy resin. The thermal expansion produced from the increased compression between the epoxy resin and braided preform will cause the extra internal stress and local deformation. A coupled thermal-stress closed loop will be formed during transverse impact. Compared with braided preforms with and without axial yarns, we found that the axial yarns improve heat energy absorption and impact damage tolerances, while impede impact damage growth.