On fracture criteria for mixed-mode crack propagation in functionally graded materials

This paper addresses mixed- mode crack growth in two-dimensional functionally graded materials, and assesses the predictive capability of some fracture criteria on both crack growth direction and crack initiation condition. Automatic simulation of mixed-mode crack propagation in homogeneous and functionally graded materials is performed by means of the finite element method in conjunction with a remeshing algorithm. Crack growth simulation consists of iterative procedures for the calculation of mixed- mode stress intensity factors by means of the interaction integral method, determination of crack growth direction and crack initiation, and local automatic remeshing along the crack path. The present approach requires a user-defined crack increment at the beginning of the simulation. Crack trajectories obtained by the present simulation are compared with available experimental results.