Combination of Element Subdiscretization, Singular Element, and Displacement Jump Enrichment for Simulating Progressive Elastoplastic Fracture

In this study, a strategy combining element subdiscretization, singular element, and displacement jump enrichment was developed to simulate crack propagation in elastoplastic materials. The background element mesh is independent of the crack path. The element enveloping the crack tip is subdiscretized to subtriangular quarter-point singular elements to represent the singularity there. The elements fully or partly split by the crack were enriched with the Heaviside function to reflect the displacement discontinuity across the two sides of the crack. The proposed method possesses an attractive advantage of being able to employ nearly all the available nonlinear models of finite element method (FEM) directly in crack tip region by using stress singular element instead of asymptotic singular function. Here, the Gurson–Tvergaard–Needleman (GTN) model was employed as crack growth law in elastoplastic materials. The proposed strategy was validated by several numerical simulations of crack propagation in elastoplastic materials including scenarios of mixed fracture mode and nonmonotonic loads.