Determination of Rolling-Element Fatigue Life From Computer Generated Bearing Tests

Abstract

Two types of rolling-element bearings representing radial loaded and thrust loaded bearings were used for this study. Three hundred and forty (340) virtual bearing sets totaling 31400 bearings were randomly assembled and tested by Monte Carlo (random) number generation. The Monte Carlo results were compared with endurance data from 51 bearing sets comprising 5321 bearings. A simple algebraic relation was established for the upper and lower L₁₀ life limits as function of the number of bearings failed for any bearing geometry. There is a fifty percent (50%) probability that the resultant bearing life ill be less than the calculated. The maximum and minimum variation between the bearing results life and the calculated life correlate with the 90-percent confidence limits for a Weibull slope of 1. 5. The calculated lives for bearings using a load-life exponent p of 4 for ball bearings and 5 for roller bearings correlated with the Monte Carlo generated bearings lives and the bearing data. STLE life factors for bearing steel and processing provide a reasonable accounting for differences between bearing life data and calculated life. Variations in Weibull slope from the Monte Carlo testing and bearing data correlated. There was excellent agreement between percent of individual components failed from Monte Carlo simulation and that predicted.

Presented at the 58th Annual Meeting in New York City April 28–May 1, 2003

KEY WORDS:

• Rolling-Element Bearings
• Life Prediction
• Weibull Analysis
• Computer Simulation
• Monte Carlo Analysis

Notes

Presented at the 58th Annual Meeting in New York City April 28–May 1, 2003