Maintenance Policies for Stochastically Failing Equipment: A Survey

This paper is a survey of scheduling policies for stochastically failing equipment. The development of these policies has relied on a variety of mathematical techniques. This reliance together with the diversity of the applications has sometimes obscured the underlying structure that is common to all these policies. The primary purpose of this survey is to identify this common structure and thereby clarify the relationships existing among the various maintenance policies. With this clarification in mind, it is hoped that the survey will provide a convenient introduction to the problems of scheduling maintenance for equipment subject to stochastic failure. The second purpose of the paper is to identify both the boundary separating scheduling problems that have been solved from interesting scheduling problems awaiting solution and the boundary separating theoretical solutions already available from applications of these solutions to practical problems. The progress of future theoretical and applied research in this field will be affected by the present positions of these boundaries. Even a crude measurement of these positions should enable us to predict the direction of future research.