Limitations of the modelling of crack propagating through heterogeneous material using a phase field approach

The modeling of crack propagation in a heterogeneous material using a phase field model is studied numerically in a simple test case: the crack meets a wedge of higher fracture energy. It is shown that when the crack cannot enter the wedge, phase field results are in qualitative agreement with theoretical predictions with moderate quantitative discrepancies. When the crack can propagate in both regions, numerical results show that the interplay of diffuse interface modelling used in the phase field model with the interface between the two regions induces spurious effects that are unphysical.