XFEM Analysis of the Effect of Fiber Volume Fraction on Crack Propagation in Fiber Reinforced Ceramic Matrix Composites

The mechanism of crack propagation near the interphase plays an important role in the failure procedure of ceramic matrix composites. The aim of this paper is to examine the effect of fiber volume fraction on the crack propagation. A three-phase unit-cell model was used to describe the micro-structure of fiber reinforced ceramic matrix composites. The interphase between fiber and matrix was modelled as a finite-thickness cylinder around the fiber. The extended finite element method (XFEM) was applied to simulate the crack initiation and propagation in the unit-cell. Without the definition of crack path priori, the approach based on XFEM can simulate the arbitrary path of cracks growing in the composites. The crack patterns and stress-strain responses for different fiber volume fraction were compared. In particular, the penetration/deflection mechanism when the matrix cracks grow to the interphase was analysed and compared. The results show that the initiation and propagation of the secondary crack/cracks were significantly influenced by the fiber volume fraction. (paper)