Compression-shear mechanical behavior and damage evolution of needled SiC/C-SiC composites under high temperature

Needled SiC/C-SiC composites are quasi-three-dimensional ceramic matrix composites and candidate materials for extreme temperatures. This study conducted compression experiments on needled SiC/C-SiC composites from room temperature to 1300℃ with loading angles from 0° to 90°. High-precision and total-factor geometric information of the composites was obtained using SEM and X-CT, providing basis for establishing the finite element model. A SiC/SiC fiber bundle damage constitutive model based on micro-mechanical analysis was coupled into the finite element model via ABAQUS UMAT subroutines to simulate the compression-shear process of needled SiC/C-SiC composites, and the simulation and experiment results were compared and analyzed. The results show the decrease in temperature and the increase in normal stress enhance the shear strength of needled SiC/C-SiC composites. The length of pull-out SiC fiber decreases with increasing temperature, indicating that high temperature weaken the toughness and strength of needled SiC/C-SiC composites. The finite element model effectively describes the damage evolution and stress–strain behavior of needled SiC/C-SiC composites. The short C fiber layers and needled regions damage, SiC matrix damage, and SiC/SiC fiber bundles damage occurred sequentially with an increase in compressive stress. These modelling methods can serve as a foundation for the design and strength assessment of ceramic matrix composites.