Abstract: In order to maintain the operational reliability of equipment during life cycle, the advantages and disadvantages of the periodic preventive maintenance model and the sequential preventive maintenance model are analyzed. A three-stage periodic preventive maintenance model is proposed based on the equipment maintenance practices. Three models, i.e., periodic preventive maintenance model, sequential preventive maintenance model and three-stage periodic preventive maintenance model, are constructed by taking the minimum cost rate of equipment life cycle under the reliability constraints as the optimization objective. The optimal preventive maintenance frequencies and intervals of equipment life cycle of each model are obtained. The case study results show that, under the same conditions, a high reliability and a low cost rate of equipment during life cycle can be obtained by using the three-stage periodic maintenance model. Moreover, it can also closely integrate the maintenance operation practices, as well as has a good feasibility and generalizability. Key

Key words: ordnancescienceandtechnology, reliability, preventivemaintenance, minimumcostrate, maintenancefrequency, maintenanceinterval