Optimisation of maintenance policies for a system with multiple deteriorating components

Condition-based maintenance (CbM) is a useful technique for scheduling maintenance policies aiming to reduce operating cost, improving the security of management, and ensuring the stable quality of the products. This paper models the deterioration process of a system composed of multiple components. Each deterioration process is modelled with the Wiener process. When a linear combination of the processes exceeds a pre-specified threshold, the age replacement policy will be carried out as the preventive maintenance for the system. Based on these two replacement policies, the optimized maintenance intervals are then sought. Besides, the paper also develops a cost process which considers the situation when the maintenance cost is higher than an expectation value, the decisionmaker will prefer to replace the whole system but not repair it. Numerical examples are given to illustrate the optimisation process