Development a refined numerical model for evaluating the matrix cracking and induced delamination formation in cross-ply composite laminates

In this study, at first the dominant micro scale failure modes including fiber–matrix debonding and matrix cracking are studied in 2D RVEs extracted from the layer 90° in different cross-ply laminates. To model the debonding and matrix cracking formation in RVEs, cohesive zone model (CZM) and Extended finite element method (XFEM) are applied. Then to investigate induced delamination formation originates from the tips of matrix cracking as a secondary damage mode, the cohesive surfaces are embedded at the interfaces of different plies in considered lay-ups. Generally, a parametric study is done on different cross-ply laminates with various thickness of layer 90° to obtain the in-situ strength due to matrix cracking and induced delamination by a numerical tool for the first time. The verification of results with the available analytical models shows an acceptable agreement. Then, by considering the long unit cells, the sequences of different damage modes formation are investigated numerically and some physical phenomena including the formation of new matrix cracking in the random locations between the previous cracks, matrix cracking saturation, symmetric and staggered pattern of matrix cracking formation and the axial stress redistribution due to each damage formation are represented in different [0/90_n]_s and [90_n/0]_s for the first time.