Condition-based maintenance policy for systems with a non-homogeneous degradation process

This paper investigates a condition-based maintenance policy for systems subject to a non-homogeneous degradation process. A nonhomogeneous degradation process occurs as a result of deterioration nature and the environmental effect. In the first step, it develops two maintenance models, which consider the constant inspection interval and non-periodic inspection interval. The paper then optimizes a maintenance policy with monotone preventive replacement thresholds. The optimal maintenance decision is shown as a control-limit policy, where the optimal preventive replacement threshold is monotonically decreasing with system age. An illustrative example is presented to show the effectiveness of the proposed maintenance models. The result indicates that preventive replacement can significantly improve the effectiveness of the maintenance policy and sustain system operation.