The hybrid imperfect maintenance model based on improvement factor of hazard rate and effective age

In this paper, a hybrid imperfect preventive maintenance model is proposed and analyzed for the deteriorating system. The hybrid imperfect PM model not only reduces the effective age, but also changes the hazard rate while the hazard rate are increasing with the number of PM. A minimal repair is performed whenever the system fails,. Preventive maintenances are performed at integer multiples of a fixed period. The system is replaced when a fixed number of preventive maintenances are completed. The optimal preventive maintenance interval and the number of preventive maintenance activities which obtained from the model of minimizing the cost rate of an infinite time span are examined. The feasibility of the model is illustrated by a numerical example. The model which determines the optimal maintenance interval quantitively provides decisive support for system maintenance.