Chapter 8 Optimal Quasi-Periodic Preventive Maintenance Policies for a Two-unit Series System with Dynamic Maintenance Plan

摘要

Most research on preventive maintenance (PM) assumed that a PM interval is a fixed value. However, practical PM actions usually are affected by some internal and external random factors, which make the PM interval become a limited random value rather then a fixed value. Few of the existing research consider this situation for two-unit system in their models. In this paper, a quasi-periodic PM policy for one type of two-unit series system with a dynamic maintenance plan is proposed, in which PM for U_1 is perfect whereas for U_2 is imperfect, and the dynamic PM plan is executed in each implemented period, and PM activities are performed through competing results of the dynamic PM plan and a catastrophic failure of U_2. The optimal implemented period of PM and PM number is obtained which minimizes the excepted cost per unit time of the system in long run. Finally, a numerical example is given to illustrate the proposed model.