Failure Mode and Effects Analysis Method on the Air System of an Aircraft Turbofan Engine in Multi-Criteria Open Group Decision-Making Environment

Failure mode and effects analysis (FMEA), an proactive risk management approach, has been widely applied in a variety of industries, especially in aircraft industry. In the process of implementation, the influence and uncertainty among different experts is inevitable. In order to handle the uncertainty in the assessments of FMEA experts, Dempster-Shafer evidence theory was introduced to FMEA for its flexibility and superiority in coping with uncertain and subjective assessments. However, traditional Dempster combination rule have difficulty in dealing with highly conflicting evidence that given from FMEA experts’ assessments. Moreover, experts themselves may influence each other though process such as chatting, judging, decision-making and voting. In this paper, we explore the problem of conflict evidence fusion from a correlation perspective among FMEA experts. We use ambiguity measure and Gaussian distribution to deal with the highly conflicting evidence. We use ambiguity measure to calculate the variance of Gaussian distribution. Then, we use Gaussian model to generalize expert assessments. After that, we use Dempster combination rule to fuze assessments from different experts. Finally, we calculate the risk priority number to rank the risk level of the FMEA items. The experiment results in the air system of an aircraft turbofan engine shows the efficiency and accuracy of the proposed method.

故障模式与影响分析（Failure Mode and Effects Analysis，FMEA）作为一种前瞻性风险管理方法，已在众多行业获得广泛应用，尤以航空工业为甚。在实施过程中，不同专家间的主观影响与评估不确定性难以避免。为处理FMEA专家评估中的不确定性，德姆普斯特-谢弗证据理论（Dempster-Shafer Evidence Theory）因其在处理不确定性与主观评估方面的灵活性与优势，被引入FMEA框架之中。然而，传统德姆普斯特组合规则（Dempster Combination Rule）难以处理FMEA专家评估生成的高度冲突证据。此外，专家之间可能通过交流、评判、决策与投票等环节相互产生影响。本文从FMEA专家间的相关性视角出发，对冲突证据融合问题展开研究。本文采用模糊度测度（Ambiguity Measure）与高斯分布（Gaussian Distribution）处理高度冲突证据：首先通过模糊度测度计算高斯分布的方差，随后利用高斯模型（Gaussian Model）对专家评估结果进行建模，再借助德姆普斯特组合规则完成不同专家评估的融合。最终通过计算风险优先数（Risk Priority Number，RPN）对FMEA各项目的风险等级进行排序。针对某航空涡扇发动机空气系统开展的实验结果验证了所提方法的有效性与准确性。