A modified phase field model for predicting the fracture behavior of quasi‐brittle materials

Phase field models have a very good capability in predicting the crack path, but most of them represent the dependence of the regularization parameter on the load‐carrying capacity of structures. In this paper, a phase field model is coupled with isotropic damage model aiming to resolve this issue in the fracture simulations of quasi‐brittle materials. Damage variables are calculated by a continuum damage mechanics model based on accurate energy reduction and then regularized by the phase field model. Since the continuum damage mechanics model is combined with phase field method, tensile strength of material is employed for calculating the damage field and phase field. Our approach can predict the accurate load‐carrying capacity independent of the regularization parameter while maintaining the precision of the crack path prediction. Three benchmark problems are solved to demonstrate good performance of our approach, and results are compared with those by the damage mechanics model or by the standard phase field model.