3D Nonlinear XFEM Simulation of Delamination in Unidirectional Composite Laminates: A Sensitivity Analysis of Modeling Parameters

Abstract

This article presents a three-dimensional extended finite element (XFEM) approach for numerical simulation of de- lamination in unidirectional composites under fracture mode I. A cohesive zone model in front of the crack tip is used to include interface material nonlinearities. To avoid instability during simulations, a critical cohesive zone length is de- fined such that user-defined XFEM elements are only activated along the crack tip inside this zone. To demonstrate the accuracy of the new approach, XFEM results are compared to a set of benchmark experimental data from the literature as well as conventional FEM, mesh free, and interface element approaches. To evaluate the effect of modeling parame- ters, a set of sensitivity analyses have also been performed on the penalty stiffness factor, critical cohesive zone length, and mesh size. It has been discussed how the same model can be used for other fracture modes when both opening and contact mechanisms are active.