Maintenance Policies When Deterioration Can be Observed by Inspections

In this paper we examine maintenance policies for systems in which the degree of deterioration can be observed through inspections. We develop a Markovian model in which the holding times in the various states are exponentially distributed. The costs incurred include costs of inspections, state occupancy costs, costs of preventive repairs, and the costs for repairing a failed system either at an inspection event or immediately after the occurrence of a malfunction. The policies examined include the scheduling of inspections and preventive repairs so that the total expected cost per time unit is minimized.