推力轴承典型故障的FMEA量化分析方法

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.