The degradation-rate-reduction preventive maintenance policies with warranty in a finite time span

A system normally has a finite useful life. The new system in each replacement cycle seldom has exactly the same characteristics and properties. However, maintenance problems are usually defined over the infinite time span where the system is assumed to have the same conditions and costs in each replacement cycle. This assumption might not be practical. Therefore, the purpose of this research is to develop the optimal preventive maintenance (PM) policies with degradation rate reduction over a finite time span under a warranty consideration by minimizing the expected total maintenance cost. Two cases are studied and compared, one is no warranty provided and the other is with a given warranty period. For the second case, two policies, performing and not performing PM within the warranty period, are examined. In this paper, the algorithm for searching the optimal solution is presented. Examples are given and the sensitivity analysis is also provided.