Maintenance strategy for two-unit multi-state deteriorating systems concerned with failure interactions

Failure interactions should be taken into consideration when determining maintenance strategies since most engineering systems, especially mechanical systems, are susceptible to failure interactions. In this paper, a two-unit multi-state deteriorating system in continuous inspection is studied. It is assumed that the system can consecutively deteriorate into several discrete states. As for either unit of the two-unit multi-state deteriorating system, its failure rate and deterioration rate depend not only on the state of the unit itself but also on the state of the other unit. The paper proposes a continuous-time Markov process model to obtain an optimal maintenance strategy. Furthermore, a numerical example is given to illustrate the proposed maintenance strategy.