Computational analysis of mixed-mode fatigue crack growth in quasi-brittle materials using extended finite element methods

In the present paper an extended finite element method (XFEM) containing strong discontinuity within elements is introduced and implemented in the commercial general purpose software ABAQUS. The algorithm allows introducing a new crack surface at arbitrary locations and directions in elements. To consider fatigue crack nucleation and propagation in quasi-brittle materials the XFEM is combined with a cyclic cohesive model. Accumulative material damage is described by separate evolution equations. The crack path is completely independent of the mesh structure but determined by the mixed-mode loading cases. Numerical simulations illustrate the ability of this method to simulate fracture with unstructured meshes. The computational results agree with known fracture experiment data. Known fatigue observations can be predicted using the present model.