A condition-based maintenance policy for a system deteriorating with age and usage

The rapid development of sensor and maintenance technologies support the implementation of a Condition-Based Maintenance (CBM) policy. The CBM policy is an effective way for reducing or even eliminating failure of a system and hence it will minimize the maintenance cost and increase the system's availability and productivity. In this study, we propose a CBM policy with periodic inspection to control the system's deterioration level. The deterioration is modelled by using a Gamma process with its shape parameter is assumed to be affected by the system's age and usage. The maintenance action is imperfect in the sense that it restores the level of the deterioration to a fixed level that is not as-good-as-new condition. We use a simulation approach to simulate the deterioration process and the impact of maintenance action to the deterioration level, and to find an optimal inspection interval for a given preventive threshold, which minimizes the total maintenance cost.