Sequential Preventive Maintenance Policy for Repairable System

In this paper, we consider a sequential preventive maintenance(PM) model, which is the extension of Cha et al.(2001) PM model. They generalize the failure rate model proposed by Canfield(1986) by assuming that after each PM not only the PM slows down the degradation process of the system but also reduces down the system failure rate by a certain fixed amount. We develop the optimal PM policies based on the sequential PM model, in which the time intervals between two consecutive preventive maintenances are unequal. Some numerical examples are presented for illustrative purpose.