A model for rolling bearing life with surface and subsurface survival: Sporadic surface damage from deterministic indentations

Abstract

Recently, the authors published a rolling bearing life model with the ability to separate the survival probability of the raceway surface from the subsurface fatigue risk of the rolling contact. In the present paper this novel modelling approach is further developed and applied to the case of sporadic and geometrically defined plastic indentations of the raceway. This is the case of bearings lubricated with oil containing very few metallic particles. The effect of sporadic deterministic indentations on the expected life of the bearings is addressed using analytical modelling and experimentally studied in detail by conducting extensive endurance life testing of bearing with pre-indented raceways. A dent surface fatigue model is developed based on the new surface-subsurface fatigue risk approach. The model results are validated comparing the predicted fatigue lives to large number of endurance tests of bearing population samples subjected to different contact pressures and damaged with dents of different sizes and shapes. Furthermore the model is used to study the effect of dent size, load and lubrication of pre-dented bearings. In this study it is found that the lubrication quality of the rolling contact has a strong effect on the life reduction of bearings with dent damage. This correlates well with the evolution and morphology of the dent damage observed during testing.