Some Considerations In Rolling Fatigue Evaluation

Abstract

A rolling fatigue tester of simple construction, well suited to multiple-rig data gathering but also possessing considerable versatility and ease of variable control, is described. Its kinematic and elasto-hydrodynamic relationships for two commonly used test specimen configurations are also presented.

Ten such testers were employed to evaluate the rolling fatigue lives of two typical aviation gas turbine lubricants. A total of 100 tests were conducted with each lubricant, comprising 10 tests on each of the 10 testers. The test conditions were such that the operation was definitely in the boundary lubrication regime. The rolling fatigue lives of the two lubricants under these conditions were found to be nearly the same at 90 percent confidence level, despite their difference in viscosities.

Using the results obtained, an analysis was made of the statistical implications and economic considerations involved in multiple-rig rolling fatigue testing. Results presented include the effects of tester-to-tester variation, the number of tests, and the extent of test suspension. Precautions and techniques in multiple-rig rolling fatigue testing are discussed.

Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Pittsburgh, Pennsylvania, October 5–7, 1971

Notes

Presented as an American Society of Lubrication Engineers paper at the ASME/ASLE Lubrication Conference held in Pittsburgh, Pennsylvania, October 5–7, 1971