Abstract:

This paper considers a maintenance model for a deteriorating system subject to vibration monitoring, which is based on a real system of the wind machines from a steel mill. The system is replaced according to two thresholds: the number of allowable rebalances (i.e., maintenance activities) N, or the working age of the system T, whichever comes first. Once the system’s vibration measurement exceeds a specific value, a maintenance activity is carried out to restore the system to a better (but not “as new”) condition. This implies that the maintenance is imperfect and as such the operating interval after each maintenance action decreases stochastically. We develop a cost model to determine the optimal N and T, as shown by a numerical case example.