Scheduling Preventive Maintenance for a Nonperiodically Inspected Deteriorating System

Abstract

We consider the problem of scheduling maintenance activities for a stochastically deteriorating manufacturing system inspected aperiodically. The state of the system (which can only be revealed at inspection epochs) is characterized jointly by the system’s physical state (the level of damage or remaining capacity) and its virtual age. Assuming a threshold-type policy, the paper aims at minimizing the long-run average maintenance cost per unit time by determining appropriate inspection intervals and maintenance thresholds. Using the renewal reward theorem, the expected cost per cycle and expected cycle length emerge as solutions of an integral equation, and a recursive scheme is devised to solve them. We illustrate the procedure for the case when the physical state evolves as a Gamma process.