Finite deformation cohesive zone phase field model for crack propagation in multi-phase microstructures

This paper develops a unified phase field model for simulating finite deformation crack evolution and interfacial decohesion in multi-phase elastic materials. Crack propagation is formulated using a phase field model, in which the order parameter s = 1 corresponds to the crack topology. The phase field model at the interface is enhanced with cohesive zone characteristics through a cohesive potential function. The interface displacement discontinuities are regularized using an auxiliary interface phase field order parameter. The cohesive potential is associated with this interface phase field for delineating interfacial decohesion. The model is numerically implemented using a multi-pass staggered solver. Numerical examples involving different failure mechanisms are simulated for examining the performance of the proposed model. Different failure mechanisms such as interfacial debonding, crack kinking and propagation in the brittle matrix, and their interactions are captured by the model. Limited verification tests are conducted with analytical results.