The Near-Optimal Policies for the Age-Reduced Preventive Maintenance Model in a Finite Time Span Using Simulation Method

For a repairable and deteriorating system, the theoretical preventive maintenance (PM) models are usually complicated and need numerical methods to obtain the optimal PM policies since the system's hazard rate function is changed after each PM. It makes the application of the theoretical model not quite suitable for real cases. Moreover, the theoretical optimal PM solution is obtained by assuming the system is evaluated over an infinite time span. Yet, in reality, the deteriorating systems always have a finite life time. Hence, searching for an optimal PM solution in a finite time span might not be rational for a deteriorating system. Therefore, we consider using the simulation method to obtain a range of the near-optimal PM policy. The critical step of the simulation method for obtaining a near-optimal PM policy is the generation of the random variates (RV). Since the rejection method is a simple and easy-to-use method in simulating the failure process of a PM model, it is applied to generate the RVs of the time-between-failures (TBF) for the finite-time-span PM model with age reduction effect. In this research, examples of the near-optimal PM policies are presented and discussed.