Aftermarket Parts: Are They All They Are "Cracked" Up To Be?
Abstract
This report contains the results of a failure analysis investigation of a fractured main support bridge from an army helicopter. The part failed component fatigue testing while those of the original equipment manufacturer (OEM) passed. Even though the same technical data package was used by both manufacturers and there were no material discrepancies found, a great disparity existed in the fatigue test data. This has been a recurring problem within the Army and the intent of this paper is to provide some insight as to the technical reasons why this can occur. Emphasis will be placed on the effects of manufacturing processes on fatigue. Other failure analyses will be discussed in relationship to this topic. Objective: To perform a metallurgical examination comparing components fabricated by "Contractor IT" to those of the OEM, with the intent of determining the disparity in fatigue life. Conclusion: The metallurgical data collected during this investigation indicated that the difference in fatigue life between the components fabricated by IT and the OEM may be attributable to a difference in dimensions at the web where fatigue crack initiation occurred. The webs of the two OEM parts examined contained cross-sectional thicknesses that measured significantly larger than the IT components.
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 05, 2001
- Accession Number
- ADP013483
Entities
People
- Victor K. Champagne
Organizations
- United States Army Research Laboratory