The Research On Operational Reliability Of Repairable System

Corresponding to different phases of the product life cycle, this paper first drawout four different reliability concepts and their models, they are: design reliability;inherent reliability; sales reliability and operational reliability. The users care moreabout the operational reliability, which is influenced by the operating conditions(operation load, operation mode, etc), operating environment (climate factors) and allkinds of maintenance activities (depth and frequency, etc). This paper will respectivelyresearch the influence of operating environment, maintenance activities on operationalreliability of the products. The method that analyzing the operating conditionsinfluence on the operational reliability is similar with the method analyzing operatingenvironment on the operational reliability, this paper do not mainly research theinfluence of operating conditions on operational reliability.The influence of operating environment on operational reliability is often beingignored, especially in the process of failure data analysis. In this paper we will use thefield failure date of a bus fleet that has operated on one route for some years asresearch object, research the operational reliability of buses through combining withthe climate factors (temperature, humidity, rainfall) of the city where the bus fleet hasoperated. Using monthly average failure numbers of fleet as the reliability index.Firstly, Using TTT graphic analyzing its failure trending. Then using power law modeldescribing the cumulative numbers of monthly average failure numbers, when thepower law model can describe the cumulative numbers well, but its monthly failurestrength function can’t describe the monthly average failure numbers well, and wethink the main reason is that the power law model hasn’t considering the influence ofoperating environment on bus’s operational reliability. Hence we introducing theproportional hazard model and finding that the proportional hazard model can describethe monthly average failure numbers of buses well, and finding the optimumoperational environment for buses. Finally, we give the optimal interval of level onemaintenance through considering the operating environment.Maintenance can be divided into corrective maintenance and preventivemaintenance, the preventive maintenance system has great effect on the operationalreliability of the equipment. How to develop a preventive maintenance system is animportant subject. This paper develops a preventive maintenance system for the kindof series system in the sense of reliability. The operational reliability indexes of the complex system are analyzed, which executes the designed preventive maintenancesystem. And setting the availability as the index to evaluate and optimize thepreventive maintenance system.