Towards a grain-scale modeling of crack initiation in rolling contact fatigue - Part 1: Shear stress considerations

International audienceA numerical model for rolling contact fatigue has been developed using finite element method and the Tanaka-Mura micromechanical model to calculate fatigue crack threshold. Two different approaches are compared: macroscopic modeling and mesoscopic modeling which considers a Voronoi polycrystalline geometry. Smooth and dented surface contacts are considered and different methods for computing shear stress are compared. It is shown that a mesoscopic length scale consideration offers benefits over a macroscopic approach in the case of dented surface meanwhile orthogonal shear stress computation on the macroscopic model can legitimately be used in the case of Hertzian contact. The article also highlights that mesoscopic modeling allows for life scatter on fatigue crack threshold. Initiation depths are consistent with literature experiments