Aftermarket parts: Are they all they’re ‘cracked’ up to be?
This paper summarizes the results of a failure analysis investigation of a fractured main support bridge from an army helicopter. The part, manufactured by “Contractor IT,” 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.
Keywordsfailure analysis fatigue 7075 Al shot peening
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