修理工单重休假可修系统平均停机时间研究

针对修理工带有单重休假的单部件可修系统,提出了一种新的维修更换模型。假定系统是可修的,逐次故障后的维修时间构成随机递增的几何过程,系统工作时间构成随机递减的几何过程。在修理工休假时间分别为随机变量和定长的情况下,选取系统的总工作时间T和故障维修次数N为更换策略,以长期运行单位时间内的平均停机时间为目标函数,通过更新过程和几何过程理论建立数学模型,导出了目标函数的解析表达式。并根据目标函数的不同情况,通过最小化目标函数或设置停机时间阈值来获取系统最优的更换策略T*和N*。通过两个仿真例子验证了该方法的有效性。

Research of the expected downtime for repairable system with single repairman vacation

To study one unit repairable system with single repairman vacation,a kind of new maintenance and replacement model is proposed.Supposing that the system is repairable,the successive survival time of the system constitutes a decreasing geometric process stochastically,while the consecutive repair time of the system constitutes an increasing geometric process.Under the conditions that the repairman vacation time is respectively random variable and constant,replacement policy is considered based on the working age T and the failure number N for the system and the long-run expected downtime per unit time as objective function is chosen,and mathematic models is established by using renewal process and geometric process theory,the explicit expressions of the objective function are derived.According to the difference of objective functions,the optimal replacement policy T~* and N~* are obtained by minimizing the objective function or setting downtime limit.Finally,two simulation examples are given to validate the effectiveness of the proposed method.