Investigation of rolling contact fatigue crack initiation from non-metallic inclusions in bearingsWednesday (27.05.2020) 14:50 - 15:10
Offshore wind turbine bearings operate in harsh working conditions and may fail prematurely due to rolling contact fatigue (RCF). The microstructural changes associated with RCF are often reported as (i) butterfly wing formation around non-metallic inclusions, (ii) dark etching areas, and (iii) white etching cracking (WEC). Understanding these premature failures requires the study of RCF at multiple scales (macroscopic, microstructural) and stages (crack initiation and propagation). This paper presents a finite element (FE) modelling approach to evaluate RCF crack initiation originating from the inclusions. A submodel containing an inclusion is derived from the global FE model of a rolling contact. Moving Hertzian load is simulated to mimic the rolling pass and the stress history around the inclusion/matrix interface is adopted within Fatemi-Socie (F-S) critical plane approach to calculate fatigue damage. The model is coupled with an experimental statistical distribution of inclusions (type, size, and location), leading to macroscopic failure prediction. Investigating the link between RCF and white etching cracks is ongoing.