LAUSR

Thermodynamic responses of three-dimensional (3D) braided composites with different braiding angles (25°/35°/45°) under high strain rate punch shear loading were studied through experiments and simulations. Plasticity criterion, shear criterion and interface damage criterion are introduced into the developed full-scale thermal-mechanical coupled finite element analysis model. Combined with macroscopic experiments and microscopic analysis, effects of braiding angle, strain rate and thermal-mechanical coupling on 3D braided composites were discussed from stress propagation and adiabatic temperature rise process. Peak stress and energy absorption increased with braiding angle or strain rate, which increased punch shear resistance of braided composites. Finally, complex thermal-mechanical coupling damage mechanism of composites was revealed through distribution of stress and temperature. Composites eventually appeared three main damage modes: interface debonding, fiber fracture and fiber extraction. Damage and energy absorption in critical loading region were also obtained. A low temperature and low stress area formed in the middle of shear band of composites. Plastic strain and thermal strain aggravated fracture of fibers.