Maintenance planning and cost effective replacement strategies

The research of this thesis deals with facility maintenance management strategies. Quantitative approaches are employed in maintenance decision making to realize the minimum maintenance cost per unit time.;An optimal preventive maintenance (PM) and repair model for a deteriorating system with a bathtub-shaped failure rate function is developed to determine optimal replacement time and maximum allowed failure rate. PM is performed whenever the system reaches its maximum allowed major failure rate. If the system fails, either a minor repair or a major repair is carried out on it. The optimal system replacement time is the last major failure time.;Joint optimization of block replacement (BR) and periodic-review spare parts provisioning policy with used items is developed for a series system. The system BR time is coupled with the spare parts provisioning period. Spare parts are ordered and inventoried according to the demand for a BR as well as random failures before recycling the used items. The used items are selected from the immediately previous BR activity and recycled in the later part of the BR period.