Opportunistic Maintenance for Two-Component Series Systems Subject to Dependent Degradation and Shock

Abstract This work studies a maintenance policy for a system consisting of two independent and identical components in series, where each component is subject to dependent degradation and fatal shock. We use a Wiener process to model the degradation, and assume that the shock rate is an increasing function of the degradation level. To utilize the economic dependence between two components, we propose an inspection/replacement opportunistic maintenance (OM) policy. A replacement is carried out to the component of which the degradation exceeds a preventive maintenance (PM) threshold at an inspection, or a fatal shock occurs. Whenever a replacement is carried out, the other component will be replaced if its degradation exceeds an OM threshold. The optimal combination of the inspection interval, OM and PM thresholds are jointly determined by minimizing the long-run average cost, which is formulated based on the semi-regenerative properties of the system state. A numerical study is provided to demonstrate the maintenance policy.