Numerical analysis of the delamination in CFRP laminates: VCCT and XFEM assessment

This document develops a critical analysis of the capabilities offered by well-known numerical approaches such as eXtended Finite Element Method (XFEM) and Virtual Crack Closure Technique (VCCT) to predict delamination in composite materials. Despite several computational analyses having been performed so far, the study of the adequacy of using different modelling approaches in the delamination of composites is still limited. This paper addresses this matter, confronting the advantages and disadvantages offered by VCCT, a well-established numerical approach, and XFEM, a promising and relatively novel modelling technique. For this purpose, the delamination of carbon fibre reinforced polymer (CFRP) laminates is investigated with the simulation of three common tests: Double Cantilever Beam (DCB), End-Notch Flexure (ENF) and Mixed-Mode Bending (MMB). Numerical results are validated with experimental data, taken from other publications, for both modelling approaches analysed. Consistency is maintained for all finite element (FE) simulations carried out in this work to draw meaningful comparisons between XFEM and VCCT. Several interesting conclusions are extracted from this work. For instance, VCCT simulations overall have high accuracy and low computational time, while XFEM shows high capabilities to predict Mode I fracture.