A peridynamics-based cohesive zone model (PD-CZM) for predicting cohesive crack propagation

Abstract

Since Dr. Silling proposed the peridynamics (PD) theory, PD has been successfully utilized to predict brittle crack propagation problems, however, a precise PD model with the prediction ability for quasi-brittle failure is still lacking. To this end, inspired by the PD theory and the conventional cohesive zone model (CZM), a PD-CZM is proposed in this work, together with a PD and finite element method (FEM) coupling approach to accurately predict cohesive crack propagation problems. The proposed PD-CZM is a nonlocal CZM established in the frame of PD through introducing an objective and precise damage model based on the energy equivalence. In the precise damage model, the tensile stretch limit is firstly analytically determined, and the discretization error is also eliminated by introducing calibration coefficients. The proposed PD-CZM is validated by directly comparing with the conventional CZM. The comparison shows that the proposed PD-CZM can approximately produce the same results as the conventional CZM for mode-I failure, and the PD-CZM model is not sensitive to the grid size. Also, four benchmark examples concerning mode-I and mixed-mode fracture of quasi-brittle materials are studied. The predicted results including both the load-displacement curves and the crack paths are in good agreement with the experimental data and the numerical results predicted by other numerical models.