Microstructure-sensitive modeling of rolling contact fatigue

Crack nucleation, first spall generation and spall growth in rolling contact fatigue (RCF) are known to be highly sensitive to the heterogeneity of the microstructure. Yet the current state-of-the-art in the design of high performance bearing materials and microstructures is highly empirical requiring substantial lengthy experimental testing to validate the reliability and performance of these new materials and processes. We have laid the groundwork necessary to determine the influence of microstructure in RCF and related very high cycle fatigue problems. Crystal plasticity material models provide more realistic accumulations of localized plastic strains with cycling compare to homogenized J2 plasticity. With J2 plasticity, the bearing must be overloaded to capture significant plasticity near inclusions; with crystal plasticity, realistic bench test loads can be applied with plastic strain accumulation observed near inclusions in cases where RCF failure is anticipated.