Cohesive crack growth in polyethylene considering Schapery equation using XFEM

Abstract

A nonlinear rate-dependent cohesive rule based on a novel incorporation by Schapery nonlinear coefficients is suggested to model crack growth in the case of polyethylene which is well-defined through the Schapery nonlinear constitutive equation. As the matter between the crack faces in a polymeric medium like polyethylene may tolerate large strain ranges during crazing and before complete separation, it may involve stress-dependent factors as same as bulk material. A useful damage-creeping cohesive rule is selected and its creeping part is extended in a way to incorporate the nonlinear Shapery parameters. The augmented relation is fitted to both high and low constraint results and applied to an experimented medium using Extended Finite Element Method (XFEM) to evaluate its ability to properly predict cohesive crack propagation. The results are in tight agreement with the existing experimental outputs. The suggested framework may illuminate a way of expressing the damage zone in polymers using nonlinear specifications of the bulk material.