Reliability and Life Prediction Methodology - M60 Torsion Bars

摘要

The life prediction and reliability assessment of the M60 tank torsion bars were obtained from applying a methodology involving several disciplines. The disciplines included: structural mechanics, fracture mechanics, statistical reliability, mechanical testing, nondestructive examination (NDE), quality assurance (QA), and metallurgical and fractographic evaluations. The methodology was applied in order to obtain a procedure for increasing torsion bar life and enhance the reliability of the M60 tank. U.S. Army reliability performance is commonly measured in mean miles between failures (MMBF). In order to introduce a more meaningful measure of component acceptability, this report describes methods for obtaining minimum life estimate at a specified probability of survival using the Monte Carlo process. This includes predicting remaining life with known risk and an approach to perform trade-off costs or redesign for increased life. The result is a more meaningful measure of component acceptability. The reliability versus bar life computation indicated a negligible amount of life after a bar flaw was initiated in the bar. The minimum life estimates prior to crack initiation were in good agreement with frequency of actual bar failures recorded at Aberdeen Proving Grounds.