Brittle crack deflection: Phase Field vs Theory of Critical Distances

Depending on material properties and geometrical features, cracks in precracked structures can propagate collinearly or kink, eventually following a curved path. Several approaches have been proposed in the literature to study this behavior, with different complexity depending on the number of involved parameters. The novelty of this study lies in the use of a Phase Field model to predict crack paths in brittle cracked geometries under Mode I loading conditions. The approach is based on a quasi static analysis to describe the elastic phase of the tensile test, followed by the simulation of crack initiation and propagation in order to predict the full crack path. Numerical outcomes are compared with experimental results reported in the literature: the model provides accurate predictions for critical loads and crack paths. Results by the Point Method and Line Method in the framework of the Theory of Critical Distances are also provided to test the consistency of the proposed approach.