Relating Lubricant Film Thickness to Contact Fatigue

Fatigue life tests have been conducted on full-scale bearings and in contact fatigue rigs simulating roller bearing contact. Results indicate fatigue life can be related to film thickness determined from elastohydrodynamic theory. Oil film continuity studies and fatigue life tests in the contact fatigue rigs indicate frequency of peeling can be associated with percentage of metallic contact. Contouring the specimens to obtain nearly uniform stress distribution simulating modified line contact in roller bearings was effective in decreasing the incidence of peeling and the measured metallic contact over a wide range of film thickness.

The major disadvantage of the rig testing was the excessive amount of time required to obtain results comparable to the full-scale bearing test results.