An efficient enrichment strategy for modeling stress singularities in isotropic composite materials with X-FEM technique

•A new enrichment strategy with high convergence rate and low condition number.•Applying enrichment strategy to model stress singularity at multi-material junctions.•Modeling stress singularity at the crack tip terminating by bimaterial interface.•Applying the eigen-function expansion method to derive enrichment functions.•Calculation of the generalized SIFs using direct and interaction integral methods.

An efficient enrichment strategy is presented for modeling stress singularities in multi-material problems and crack-tips terminating at a bi-material interface within the X-FEM framework. The eigen-function expansion method is employed to evaluate eigen-values and asymptotic fields around singular points. The generalized stress intensity factors are defined on the basis of direct and interaction integral techniques. Numerical examples are solved for different types of eigen-values, and the convergence study is performed to investigate the accuracy of the proposed enrichment strategy. The results indicate that the proposed method has superior accuracy, higher convergence rate and lower condition numbers over the other methods.