Optimal maintenance strategy for product considering degradation level with preventive maintenance cycles

다국어 초록 (Multilingual Abstract)

In this study, we develop the maintenance policy for a used product to determine a periodic preventive maintenance cycle from the dealer’s point of view. Because replacing failed products may not be possible with used products, we introduce the concept of full refund instead of replacement. We set a repair time threshold and give a full refund, not continuing to provide a repair service for failed used product when a repair time exceeds its threshold. Otherwise, the user has only minimal repairs to the failed product, and if the dealer does not provide a full refund during the warranty period, the periodic preventive maintenance cycle is finished at the moment when the warranty expires. Given a certain cost models charged to the dealer, we develop formulas to evaluate the optimal maintenance cycle and the total maintenance cost under warranty. Assuming the process for used product failures and a Weibull distribution for the repair times, we describe the proposed policy numerically and carry out sensitivity analysis to investigate the impacts of several parameters on the preventive maintenance cycle and corresponding expected cost rate. The real application is implemented using the proposed approach and numerical examples are discussed to demonstrate the appropriateness of the methodologies derived in this paper.