Microstructure-based modeling of crack growth in particle reinforced composites

Crack growth in particle reinforced composites is significantly influenced by the size, orientation, morphology and distribution of the reinforcement particles. Hence, to accurately model crack growth in such a system it is important that the complex microstructure of the particles be taken into account and not approximated by circles or ellipses. In this paper, the effects of particle morphology and distribution (homogeneous and clustered) on crack growth have been studied using the finite element method. The degree of particle clustering in aluminum/silicon carbide composites was quantified by the coefficient of variance in the mean near-neighbor particle spacing, and cluster size distributions obtained by an image analysis technique. Two-dimensional linear elastic fracture mechanics principles were used to propagate the crack, to obtain the local stress intensity values, and to gain an understanding of the local stress state. Predictions from these analyses were in agreement with experimental observations of crack growth in Al–SiC systems.