Modeling delamination in composite laminates using XFEM by new orthotropic enrichment functions

In this research, the extended finite element method (XFEM) is improved for modeling interfacial cracks between two orthotropic media by new set of orthotropic enrichment functions. New set of bimaterial orthotropic enrichment functions are developed and utilized in XFEM analysis of linear elastic fracture mechanics of layered composites. Interlaminar crack-tip enrichment functions are derived from analytical asymptotic displacement fields around a traction free interfacial crack. In this procedure, elements containing a crack tip or strong/weak discontinuities are not required to conform to those geometries. The domain interaction integral approach is also adopted in order to numerically evaluate the mixed-mode stress intensity factors. A number of benchmark tests are simulated to assess the performance of the proposed approach and the results are compared to available reference results.