Evaluating the Validity of Rolling Contact Fatigue Test Results

Abstract

The study described herein was conducted in order to validate the performance of a pair of two-headed rolling contact fatigue test machines acquired at a U.S. Navy facility. The purpose was to assess whether the machines yielded Weibull distributed fatigue lives with no systematic difference between the machines or between the heads within a machine. The test plan comprised of 24 runs on each machine yielding a total of 48 failure lives. The runs were balanced across machines, test heads, and specimens and thus allowed the identification of sources of possible non-Weibull behavior of the observed lives. The effects of these sources are not considered grave enough to invalidate test comparisons made in the usual way. They do raise the possibility, however, that if the design of the test machines could be improved to remove the sources of random variability, material comparisons could be made more precise, permitting material or lubricant effects on rolling contact fatigue to be detected in fewer tests.

Keywords:

• Statistical Analysis
• Rolling Contact Fatigue

ACKNOWLEDGEMENT

The data used herein were generated at the Propulsion and Power Division of the Naval Air Warfare Center, Aircraft Division, Patuxent River, MD, as part of an effort to qualify rolling contact fatigue (RCF) machines. The authors would like to thank Darrell Grant and Charles Huffman for providing engineering and management support. Thanks to Carolyn Purcell and Leslie Leigh for technical support. We also thank the test technician, Ronald Stephenson, for the excellent execution of a complicated test plan. Thanks also to Leo Rez of LZR Enterprises, LLC, for providing test procedure training and machine overhaul.

Review led by Dong Zhu