【摘要】 作为典型摩擦学系统的推力轴承是大型发电机组的核心承载部件，受到故障数据不足与失效模式耦合的制约，面临失效评估与预测方法缺位的难题.针对推力轴承典型故障的量化分析，提出了1种不依赖故障数据数量、综合失效模式耦合推理的推力轴承失效模式与影响分析(Failure Mode and Effect Analysis,FMEA)方法.首先，通过引入反馈环节的方式建立考虑失效关联性的推力轴承故障树，理清各失效模式的发生脉络；其次，通过调研统计对底事件进行相对概率赋值，结合故障树实现失效模式的相对频度表征；再次，考虑系统与局部影响，通过分层评估的方式联合概率重要度与中间事件次数进行失效模式严酷度表征；最后，通过可检测手段分析确定各失效模式的可检度指标，并联合上述3项指标计算综合风险优先系数(Risk Priority Number,RPN).研究结果表明，轴瓦磨损是推力轴承RPN最大的失效模式，而润滑失效最易诱导其他失效.与传统方法对比，FMEA量化分析方法在乏数据时可降低频度评价主观性，失效耦合时可解耦分析确定关键级联失效模式.更多还原

【Abstract】 As typical tribo-systems, thrust bearings serve as the core load-bearing components of large power-generating units. They suffer from the absence of failure assessment and prediction, which is exacerbated by the scarcity of fault data and the coupling of multiple failure modes. Therefore, a failure mode and effects analysis(FMEA) method that does not rely on the amount of fault data and integrates reasoning for coupled failure modes is proposed: First, a fault tree that accounts for failure dependencies is established for thrust bearings by introducing feedback loops, clarifying the occurrence context of each failure mode. Second, based on survey statistics, relative probabilities are assigned to basic events, and the relative frequencies of failure modes are characterized in conjunction with the fault tree. Third,considering both system-level and local effects, a hierarchical evaluation approach is used to characterize the severity of failure modes by combining probability importance with the frequencies of intermediate events. Finally, detectability is determined by analyzing the detection methods for each failure mode, and the comprehensive risk priority number(RPN) is calculated by integrating the three indicators. The results show that pad wear has the highest RPN, whereas lubrication failure is the most likely to induce other failure modes. Compared with traditional methods, the quantitative FMEA approach reduces the subjectivity of frequency evaluation under data-scarce conditions and performs a decoupling analysis to identify critical cascading failure modes when failures are coupled.更多还原