Modifying the Lambda Ratio to Functional Line Contacts

Lambda ratio, the lubricant film thickness divided by the composite roughness within an operating rolling element bearing, has been recognized for more than 25 years as an important contact parameter related to bearing performance, primarily fatigue life. This paper considers a simplified method of functional filtering within a bearing contact that provides a more appropriate composite roughness for a wider range of bearing sizes and loadings. The concept was tested with a series of regression models of standard and modified lambda ratios, including the uncoupled lambda parameters. The models were rated using three different statistical indices to assess how each model accounted for the variation present in a large collection of bearing test data.