Maintenance optimisation of a series-parallel system with multi-state components considering economic dependence

The maintenance optimisation of a series-parallel system is a practical and imperative research topic. However, existing research on the maintenance of a series-parallel system largely ignores the economic dependence among components, which can increase the maintenance cost. In addition, most current research assumes that the components in a system only have two states, while condition monitoring techniques can often provide more detailed health information of components. This paper proposes a maintenance optimisation method for a series-parallel system with multistate components considering economic dependence. The state of a subsystem is defined based on both the combination of component states and current maintenance actions. Using the results of the steady-state analysis of subsystem states, the average revenue per unit time of the system is calculated as the objective function of maintenance optimisation. The optimal strategy is then identified by the enumerative method. A simulation study is conducted to investigate the performance of the proposed maintenance optimisation method. The results show that the proposed method can identify the optimal maintenance strategy efficiently, and the maintenance strategy considering the economic dependence can enhance the revenue significantly.