On multi-state system with interval-valued states under preventive maintenance and minimal repairs

In this paper, we develop and investigate a model for the reliability and availability of multi-state degraded system with the system states represented as interval-valued numbers. That is, the system in a certain interval-valued state can provide arbitrary value of performance between the lower bound and the upper bound. The status of the system is considered to degrade with use and we consider the case of imperfect preventive maintenance and minimal repairs. Considering predetermined system demand, the system is modeled as a continuous-time Markov process. Based on the Markov model, the availability and the reliability of the multi-state degraded system can be evaluated by solving the corresponding Chapman-Kolmogorov equations. Finally, a numerical example of deployable antenna truss is given to illustrate the proposed model.