Preventive Maintenance Strategy With Minor Repairs For Malfunction For Single-Unit Repairable System

Repairable system is an important system discussed in the reliability theory, and also is one of the main objects studied in the mathematical theory of reliability. In the study of maintenance strategy of system, periodic preventive maintenance strategy with minor repairs for malfunction is one of the most basic maintenance strategies, and has practical significance for the establishment of maintenance plans and improving the system availability.This paper focuses on preventive maintenance program centering about reliability and security. In this paper, we propose an optimization method for preventive maintenance plan with periodic minor repairs for system components.First of all, we assume that the system components can not be repaired to the new condition, preventive maintenance strategy (R,N) is based on geometric process without considering minor repair time, and the period of preventive maintenance is alterable. The period of preventive maintenance is decided by reliability, we will conduct a preventive maintenance for the system when the system reliability decreases to a certain value. The system will be carried out minor repairs when it is disabled. Minor repairs can only restore the working status of the system components. Minor repair time is not considered. The system will be replaced when the number of preventive maintenance reaches N. And then we deduce the minimum spend within per unit time when the system is long-term running, establish the preventive maintenance policy model of the cost of maintenance on this basis, give numerical examples to solve the model, and derive the optimal preventive maintenance strategy.Secondly, this paper focuses on preventive maintenance strategy (R,N) based on geometric process with considering minor repair time. The period of preventive maintenance is also decided by reliability. We will carry on minor repairs for the system when it is disabled. We assume that the minor repair time is equal within a period and is subject to the geometric process with random increment between periods. The system will be replaced when the number of the system preventive maintenance reaches N. We provide the expression of the average spend of system, solve the model via numerical examples, and derive the optimal preventive maintenance strategy.Once more, this paper focuses on the preventive maintenance strategy based on geometric process with periodic minor repair. Taking into account the components of some mechanical systems (such as aviation system) has relatively high requirements of security and reliability, which may cause serious consequences if there are environmental failures, the period of the preventive maintenance is decided by safe working time. We will carry on preventive maintenance for the system when the safe working time of the system reaches a certain value. Similarly, we give numerical examples to solve the model, and derive the optimal preventive maintenance strategy.Lastly, we find that minor repair time indeed affect the establishment of the optimal maintenance strategy by comparison between model1and model2, the minimum repair cost of the model considering minor repair time is higher than that of the model without considering minor repair time. This is reasonable according to the above analysis. Model2is better than model3, but model3is more suitable for the maintenance system which has higher requirements of security and does not control cost via comparison between model2and model3.