A maintenance policy for a [formula omitted]-out-of-[formula omitted] system under enhancing the system’s operating time and safety constraints, and selling the second-hand components

Abstract

In this paper, a new maintenance policy for k-out-of-n:F systems is proposed, which includes age replacement and minor repairs as preventive maintenance actions. After replacing a multi-component system, some components are still usable and can be sold as second-hand products. The price of these components depends on their original lifetime and the replacement time of the system. On the other hand, managers and engineers would like to reduce the imposed costs on the system while increasing system efficiency. With this in mind, long-run average cost is considered as the objective function. In addition, the optimal parameters of the proposed policy are obtained under two constraints: a safety constraint and a constraint for enhancing the relative mean operating time. By considering the first constraint, the system engineer is confident with a desired probability that no unplanned replacement will happen to the system in a pre-specified interval. The second constraint ensures the enhancement of the mean operating time of the system by applying the proposed policy. Moreover, the classical age replacement policy has been achieved as a special case of our results. To study the effect of the model’s parameters on the optimal solutions, extensive numerical computations are performed. Finally, a real data set of the tensile strength of cables is used to demonstrate the applicability of the proposed model.