A bi-level condition-based maintenance policy for a two-component system subject to stochastic and economic dependencies

This paper investigates a condition-based maintenance policy for a two-component system subject to stochastic and economic dependencies. The stochastic dependence between components is modeled by a copula function. The economic dependence is represented by combination of maintenance activities of components as a group. A decision-making process considering both system and component levels is proposed. At the system level, the decision rule is to derive the optimal system reliability threshold which triggers the maintenance actions of components given the system’s current health state. At the component level, a maintenance efficacy indicator is proposed to support the selection of the optimal group of components to be preventively replaced. The objective is to minimize the average long-run maintenance cost rate. The grid search method and Monte Carlo simulation are jointly used to derive the optimal CBM decision. A numerical study is conducted to illustrate the effectiveness of the proposed approach in the maintenance optimization framework. A sensitivity analysis of several model parameters is also performed.