Numerical modelling of rolling contact fatigue damage initiation from non-metallic inclusions in bearing steel

Bearing failure is a cause of concern in a variety of machinery such as turbines, transmissions, drills, engines, etc. It is often associated with rolling contact fatigue (RCF) triggered from damage initiation at non-metallic in-clusions (NMI's). Experimental evidence shows that damage initiation lifetime is highly sensitive to the NMI characteristics and its bonding with the steel matrix. This study numerically investigates the role of NMI features and its bonding with the steel matrix on damage initiation lifetime. NMI characteristics modelled in this study are derived from an experimental investigation of a failed bearing. Simulation results highlight a near to instanta-neous debonding at the matrix-inclusion interface followed by accelerated crack initiation. The critical depth for damage initiation shifts towards the surface with the increase in friction coefficient between roller and raceway. The simulations also reveal that larger inclusions show earlier damage initiation, indicating a size effect. The damage hotspots from the simulation results were compared with experimental findings and a hypothesis for crack initiation from a NMI is put forward.

Automated summary

Bearing failure can occur in various machinery and is often caused by rolling contact fatigue (RCF) triggered by damage initiation at non-metallic inclusions (NMI's). This study focuses on numerically investigating the impact of NMI features and bonding with the steel matrix on damage initiation lifetime. Simulation results indicate an immediate debonding at the matrix-inclusion interface followed by accelerated crack initiation. The depth for damage initiation shifts towards the surface with increasing friction coefficient between roller and raceway, and larger inclusions demonstrate earlier damage initiation.