A phase field approach to model crack-interface interaction in ceramic matrix composites

Abstract

Ceramic matrix composites are widely applied in coatings, engines, and space vehicles because of their superior thermo-mechanical properties. Various failure modes can be possible in ceramic matrix composites, notable ones are fiber breakage, matrix cracking and fiber matrix debonding. In order to predict the failure mechanisms at microstructural level (matrix-fiber system) of such composites, understanding crack nucleation and propagation across different phases, namely, fiber, and matrix is significant. To assess structural integrity, the material parameters that govern the crack growth should be determined. Nonlocal approaches consider the interactions between infinitesimal material volumes by considering a material length scale parameter. Phase field method is one of the popular nonlocal approach to model failure in cracked solids. In the present work, phase field approach is adopted to model the crack propagation through different phases of a ceramic matrix composite at microstructural level. The performance of the proposed formulation is illustrated through representative numerical examples. The model proposed is implemented in the framework of the finite element method. Crack propagations are studied by considering two ceramic matrix composites, namely, carbon fibers in carbon matrix (C/C) composite, and carbon fibers in silicon carbide (C/SiC) composite. For the case of C/SiC composite, parametric study is conducted by varying the fiber volume fraction.