CONDITION-BASED MAINTENANCE FOR SYSTEMS WITH DEGRADATION PROCESSES AND RANDOM SHOCK UNDER WARRANTY

초록

A condition-based maintenance strategy is developed for systems subject to two dependent causes of a failure such as degradation and random shock. The degradation threshold shock model for systems have been developed under warranty considering repair service and replacement service. We investigate the relationships between random shock and degradation process which are modeled by a time-scaled covariate factor and the relationship between various degradation processes. Fatal shock which needs replacement service for system immediately and nonfatal shock which needs repair service for failed parts are considered. For a nonfatal shock, there are two direct effects, slowly accelerations and sudden accretion jumps on the degradation levels. There are degradation limits for repair service and for replacement service, respectively. Degradation level may jump to the degradation limit for the replacement service or/ and may increase to the other degradation limit for repair serivce. In this study, we consider not only the degradation process but also random shock model and decision variables are determined for the degradation threshold shock model. Total expected cost is minimized to determine an optimal maintenance cycle and optimal length of warranty period for the warranty cost analysis. Additionally, warranty service time for repair service and replacement service is considered with warranty service time limit to increase customers’ satisfaction. Suppose that the system deteriorates with age, we illustrate the proposed approach using numerical applications and investigate the influence of relevant parameters on the optimal solutions for the maintenance policy. © ESREL 2021. Published by Research Publishing, Singapore.

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