M.S. Fallah Nezhad - Assistant Professor of Industrial Engineering, Yazd University, Yazd, Iran
A. Mostafaeipour - Industrial Engineering Department, Yazd University, Yazd, Iran,
M.S. Sajadieh - Department of Industrial Engineering, Amirkabir University of Technology, Tehran, Iran,

In order to perform Preventive Maintenance (PM), two approaches have evolved in the literature. The traditional approach is based on the use of statistical and reliability analysis of equipment failure. Under statistical-reliability (S-R)-based PM, the objective of achieving the minimum total cost is pursued by establishing fixed PM intervals, which are statistically optimal, at which a decision to replace or overhaul equipments or components is made. The second approach involves the use of sensor-based monitoring of equipment condition in order to predict occurrence of machine failure. Under condition-based (C-B) PM, intervals between PM works are no longer fixed, but are performed only when needed . It is obvious that Condition Based Maintenance (CBM) needs an on-line inspection and monitoring system that causes CBM to be expensive. Whenever this cost is infeasible, we can develop other methods to improve the performance of traditional (S-R)-based PM method. In this research, the concept of Bayesian inference was used. The time between machine failures was observed, and Bayesian inference is employed in (S-R)-based PM, it is tried to determine the optimal checkpoints.

Statistical Models, Reliability, Preventive Maintenance, Bayesian Inference