Fault tree analysis (FTA) is an important method to analyze the failure causes of engineering systems and evaluate their safety and reliability. In practical application, the probabilities of bottom events in FTA are usually estimated according to the opinions of experts or engineers because it is difficult to obtain sufficient probability data of bottom events in fault tree. However, in many cases, there are many experts with different opinions or different forms of opinions. How to reasonably aggregate expert opinions is a challenge for the engineering application of fault tree method. In this study, a fuzzy fault tree analysis approach based on similarity aggregation method (SAM-FFTA) has been proposed. This method combines SAM with fuzzy set theory and can handled comprehensively diverse forms of opinions of different experts to obtain the probabilities of bottom events in fault tree. Finally, for verifying the applicability and flexibility of the proposed method, a natural gas spherical storage tank with a volume of 10,000 m³ was analyzed, and the importance of each bottom event was determined. The results show that flame, lightning spark, electrostatic spark, impact spark, mechanical breakdown and deformation/breakage have the most significant influence on the explosion of the natural gas spherical storage tank.

故障树分析（FTA）是分析工程系统故障原因并评估其安全性和可靠性的重要方法。在实际应用中，由于难以获得故障树中足够的海底事件概率数据，因此通常根据专家或工程师的意见来估计FTA中海底事件的概率。但是，在许多情况下，有许多专家有不同的意见或不同形式的意见。如何合理地汇总专家意见是故障树法在工程应用中的一个挑战。本文提出了一种基于相似度聚合方法（SAM-FFTA）的模糊故障树分析方法。该方法将SAM与模糊集理论相结合，可以综合处理不同专家的不同意见，以获取故障树中底部事件的概率。最后，为验证所提出方法的适用性和灵活性，使用了一个容积为10,000 m的天然气球形储罐分析了^3个，并确定了每个底部事件的重要性。结果表明，火焰，雷电火花，静电火花，冲击火花，机械击穿和变形/破损对天然气球形储罐的爆炸影响最大。