Mixed mode fatigue crack growth analysis of cracked aluminium panel repaired with composite patches using extended finite element method

Extended finite element method (XFEM) is one of the strongest numerical methods that its basis is finite element method. In this method, using of enriching the nodes and increasing of their degrees of freedom (from 2 to 4 or even upto 10) virtually and without verifying the mesh and geometry of discountinuty, can model the system. In FEM crack geometry must be align with mesh edges which needs changing meshes in every steps of crack propagation and take so much time and too many analysis. One of the main objectives in this study is the expression of a novel method for modeling fatigue crack growth more easily and achieve the life of the structure by calculating the stress concentration factors. In this paper by using XFEM in ABAQUS, real 3D crack trajectory in single side repair has been simulated. Variation of fracture parameterin thickness direction of cracked panel with different patch lay-ups has been studied. In this paper, tests include mixed mode crack propagation. By examining the XFEM results of this research, FEM and experimental results of previous studies, it was found that the results of XFEM in comparison to experimental results have less error.