Optimal maintenance strategies for coherent systems: A warranty dependent approach

Abstract

We investigate optimal maintenance models for warranted coherent systems consisting of n components (n≥1). The system is under a warranty policy with two consecutive phases under which the manufacturer’s commitment goes in two different forms. In Phase I, upon the system failure, the failed components are replaced with new ones and a corrective maintenance is conducted on the whole system. If the system failure occurs during Phase II, only minimal repair is performed on the components. Following expiration of the warranty time, the customer is solely responsible for maintaining the system who, for a fixed length of the time period, replaces the failed components and preventively maintains the system at the end of such period. During the maintenance period, the same maintenance as that of in Phase I of the warranty period is conducted. Such a maintenance model can be considered as a generalization of the age-based maintenance model for a system under warranty model. We investigate, from the manufacturer’s and customer’s perspectives, the optimal length of each phase in the warranty period, and the optimal planned time of preventive maintenance based on some imposed cost functions, respectively. Numerical examples are provided to illustrate the proposed optimal maintenance models.