相依多模失效下冷贮备系统最优切换及视情维护决策

针对存在冲击影响的冷贮备系统,研究其最优切换及视情维护决策问题.首先,在系统结构和切换式运行和维护特性分析的基础上,制定基于周期切换和状态检测的切换式离线视情维护策略;其次,建立累积冲击过程影响下系统退化所致的软失效和极端冲击过程所致的硬失效竞争可靠性模型;再次,通过分析两类冲击过程影响下系统运行与备用设备交替使用、维修过程中的状态转移特性,重点推导各检测周期时刻系统状态概率分布的迭代计算模型;然后,以系统平均费用率最小为目标,建立解析决策模型,以求解系统的最优切换周期和维护阈值.最后,以矿井主通风系统为案例验证策略及模型的有效性,并分析模型对参数的灵敏度.结果表明,系统的最优维修策略随机冲击影响的不同而变化显著.

Optimal switching and condition based maintenance decision of cold standby system subject to dependent multimode failures

In this paper, the optimal switching and condition based maintenance decision of a cold standby switching system with random shocks is studied. Firstly, an off-line condition based maintenance strategy with periodic switching and inspection is proposed, based on the analysis of the structure and maintenance characteristics of the switched operation system. Secondly, the reliability models of competitive failure, between soft failure caused by system degradation subject to cumulative shock process and hard failure caused by extreme shock process, are established. Then, the iterative model of probability distribution of system state at each inspection point is derived by analyzing the characteristics of state transition in the process of alternate use and maintenance of operation and standby equipment subject to two kinds of shock processes. Furthermore, an analytical decision model is established to minimize the average cost rate to obtain the optimal switching period and maintenance threshold. Finally, the effectiveness of the strategy and the model are verified by taking the coal mine main ventilator system as the example, and the sensitivity of the model to the parameters is analyzed. The results show that the optimal maintenance strategy of the system changes significantly with the impact of shocks.