Maryam Zaghian - Department of Industrial engineering , Iran university of science and technology,Tehran,Iran
Neda Vahedi
Hamid Babaei
Kamran Shahanaghi

In this paper a method for optimizing maintenance thresholds policy and time of inspection for a stochastically critical system suffering from continuous deterioration is proposed. The authors have executed a lexicographic method to tackle the problem. At the first step preventive maintenance thresholds, preventive replacement thresholds and inspection periods are determined to constrain failure probability to a pre-specified value (P). Afterwards from the results derived from the first phase, the values that minimize total maintenance costs per time unit are selected. It is assumed that each preventive maintenance action does not return the system state to its initial state and the system state improves according to a random coefficient ( t ). The exact computation and evaluation of the stationary probability distribution of the system state at infinity is impossible and even its approximation is tricky and time consuming, Therefore Monte Carlo simulation is utilized to optimize our model. The novelty of the present work stems from the fact that system failure is constrained to a prespecified value for the supposed critical system.

Condition Based Maintenance (CBM), Constraining failure probability, Cost optimization, Monte Carlo simulation