A novel SAM/X-FEM coupling approach for the simulation of 3D fatigue crack growth under rolling contact loading

The present work proposes a novel efficient numerical approach for the simulation of three-dimensional propagation of non-planar frictional crack under Rolling Contact Fatigue (RCF). The developed model relies on a global-local strategy involving the Semi-Analytical Method (SAM), dedicated to the resolution of 3D contact problems, and the eXtended-Finite Element Method (X-FEM), dedicated to the solving of 3D crack problems. Similar to a submodeling technique, it consists in performing a local X-FEM analysis of the 3D RCF crack problem by means of boundary conditions extracted from a prior global SAM analysis which solves the contact problem between two semi-infinite bodies without considering the crack. A powerful procedure for the transfer of relevant mechanical quantities between the SAM and X-FEM models is developed. It allows the use of non-matching and non-conforming discretization scheme for the global SAM model and the local X-FEM model, particularly worthwhile for the pre-processing stage. An initial arbitrary stress profile can be considered to investigate the influence of residual stresses on crack behavior. The non-intrusive SAM/X-FEM coupling is integrated into a fully automatic crack propagation algorithm. This provides a powerful and user-friendly tool suitable for industrial applications, which easily handles 3D long non-planar frictional crack growth in the region of interest. After introducing some details concerning the implementation of the model, a validation of the innovative SAM/X-FEM coupling is performed by using results from the literature. Furthermore, a practical example demonstrates the great potential of this novel numerical technique to simulate in a fast, robust and accurate way the 3D complex behavior of fatigue crack under moving contact.