Reliability engineering approach to achieve RCM for mechanical systems — 2012

The foundation for reliability-centered maintenance is the characterization of reliability failure models. Reliability is currently defined as the probability that a part will function without failure for designated mission durations under specified conditions of use. This paper proposes that reliability should be defined as the probability that a part will function without failure under risk characterized stress loads for specified operational and ambient conditions of use. Empirical reliability math modeling suggests that time does not cause part failure and therefore Time-to-Failure, TTF, based reliability math models are meaningless. Findings from current research in reliability math modeling show that failure mechanisms cause part failure, and that stress based reliability math models are meaningful. Reliability math models are fit from failure analysis and (1) characterize part failure condition indicators that allow implementation of condition-based maintenance, or (2) characterize part hazard functions that allow implementation of stress-directed maintenance.