Recent efforts toward modeling interactions of matrix cracks and delaminations: an integrated XFEM-CE approach

This paper presents a novel integrated approach using the extended finite element method (XFEM) and cohesive elements (CEs) for modeling three-dimensional (3D) delaminations, matrix cracks, and their interactions in progressive failure of composite laminates. In the proposed XFEM-CE approach, the matrix cracks are explicitly modeled by the XFEM through nodal enrichment and element partition, and the inter-ply delaminations are modeled by cohesive elements through traction–separation law. An XFEM-based cohesive element enrichment scheme is developed in order to properly model the interactions between the delaminations and matrix cracks. It is critical to enrich the cohesive elements at the local juncture where cracks meet, in order to obtain the correct crack path interactions. Examples are presented for failure analysis of double-cantilever-beam and end-notch-flexure laminates with different layups. The results show strong explicit matrix crack–delamination interactions in these laminates. This work presents another significant development of a computational platform for realistic modeling of progressive damage in composites.