A tradeoff BX life and its applications

A product usually consists of multiple components. Product design needs to specify the life limit of each component. The life limit can be viewed as a preventive replacement age and expressed as a BX life. A large value of X means low cycle reliability but small life loss. As such, X must be appropriately specified so that a good tradeoff between reliability and life can be achieved. This paper presents an approach to determine the value of X for a component with a known life distribution. The approach divides the expected useful life into two parts. One part is from the items failed before BX and the other part is from the items replaced preventively at BX. There exists a unique BX, which makes the latter part achieve its maximum. This BX life can achieve a good tradeoff between reliability and life, and hence is termed as tradeoff BX life. The potential applications of the tradeoff BX life are discussed, and the tradeoff BX lives for the Weibull, gamma and lognormal distributions are derived. A real-world example is included to illustrate the appropriateness and usefulness of the results.