Maintenance Optimization of Two-Units System with General Time Distributions

Abstract

This paper proposes a method to solve the steady state availability of two-units series system with all the time distributions are general. And the optimization of system maintenance is researched as well. Since the failure rates of two different units are not following exponential distribution, the method used in Markov process won't help. We supply sojourn time as variable to describe the system in a general Markov process and the transition of system states are obtained. After simplify the system state equations, the relation between states is derived and the probability of each state in steady state can be calculated for solving system's steady state availability. Further, a policy of preventive maintenance (PM) is introduced which changes the system state space and the transition of states. On the basis of the solution method, the availability of new model is easy to solve. Then we present the procedure to identify PM interval for optimization. Finally, numerical examples are given to validate the proposed method.