Abstract: For solving the problem of insufficient basic event failure rate in fault tree analysis, a fuzzy fault tree analysis method is proposed in analyzing complex systems. By converting expert judgments into specific fuzzy probability values, the probability of basic events occurring is determined, and the probability of the top event and critical importance of the fault tree are calculated. Taking the electric drive axle system of heavy-truck as an example, by establishing a fault tree for electric drive axle not working, and through quantitative analysis of fuzzy fault tree, the key fault factors affecting system reliability are confirmed, and provides certain reference value for relevant workers.

Key words: Fuzzy fault tree; Trapezoidal fuzzy number; Reliability analysis; Heavy truck electric drive axle

摘要： 为解决故障树分析时无法获取足够基本事件故障率的问题，文章研究提出模糊故障树 分析法。通过将专家判断转化为具体的模糊概率值，从而确定基本事件的发生概率，并完成 对故障树顶事件发生概率和关键重要度计算。以某重型卡车的电驱动桥为例，通过建立电驱 动桥不工作的故障树，对模糊故障树进行定量分析，确定了影响系统可靠性的关键故障因素， 为相关工作者提供一定的参考借鉴价值。

关键词: 模糊故障树；梯形模糊数；可靠性分析；重卡电驱动桥