An investigation into various failure criteria on rolling contact fatigue through an improved probabilistic model

Abstract

This work presents an improved probabilistic continuum damage mechanics (CDM) finite element (FE) model to simulate the degradation of material as a function of cycle in order to estimate rolling contact fatigue (RCF) life of critical tribological components. Traditionally, CDM-FE models consider the shear reversal to be the damage causing stress in RCF; however, in this investigation, the CDM-FE model also considers the octahedral shear stress, the maximum shear stress, the Fatemi-Socie criteria, and the Dang Van multi-axial fatigue parameter as failure criteria. The critical damage material parameters (σr and m) were obtained from open literature torsion fatigue results. Further, to enable a probabilistic CDM-FE model, the critical damage material parameters (σr and m) were described via a distribution as opposed to fixed values. This allows for the variation of a material’s resistance to fatigue that is present in both torsion and rolling contact fatigue to be captured. Forty unique material microstructure models were created using Voronoi tessellations to capture the random pathways for crack growth. RCF simulations were conducted at five contact pressures between 1.0 GPa and 3.4 GPa. Regression analysis between contact pressure and cycles to failure for each of the failure criteria yielded five unique predictive fatigue life equations, one for each failure criteria investigated. These fatigue life equations were then compared to Lundberg-Palmgren theory considering appropriate material and lubrication factors. The results demonstrated that the Fatemi-Socie and shear stress reversal failure criteria compared favorably to Lundberg-Palmgren theory. Notably, the Fatemi-Socie criteria exhibited closer agreement with Lundberg and Palmgren theory at higher contact pressures, in contrast to the shear reversal criteria.