An optimal maintenance policy based on partial information

This paper proposes an integrated model for maintenance scheduling of parallel systems whose failures are detected by inspections. A common characteristic of such systems is that the system failures are detected only by inspections and the failure of a component may not cause its system to fail. As such, the failure may not be immediately detected and the random (disruption) time at which the number of failed components reaches a certain predefined number d may therefore be unknown. For such systems, scheduling maintenance policy is a difficult task, which is tackled in this paper. The main issue considered here is to get an estimate of the disruption time on the basis of inspection point process observations in the framework of filtering theorem. The paper develops a unified cost structure to jointly optimise inspection frequency and replacement time for the system when the lifetime distribution of a component follows the Weibull distribution. Numerical results are provided to show the application of the proposed model. In addition, a sensitivity analysis is performed to examine the effect of maintenance parameters on the model.