Critical strain as a metric for crack propagation resistance in SiCf/SiC composites

Comprehensive research on crack propagation in SiC_f/SiC composites is essential for understanding fracture mechanisms, enhancing toughening capabilities, extending service life in engineering applications, and driving new methodologies and theories in strength design. Despite their importance, the defect sensitivity and crack propagation resistance (CPR) of SiC_f/SiC composites remain underexplored, with the influence of component parameters on CPR still unclear. Herein, we develop a novel approach and propose a new three-dimensional finite element model that incorporates varying interface layer thicknesses and randomly distributed fibers, using the single-edged pre-crack beam method. By introducing the critical strain parameter, the model quantitatively evaluates fracture energy and the effects of mesoscopic components on CPR. Our findings provide valuable insights into optimizing the mesoscopic components for enhanced toughness in SiC_f/SiC composites.