基于风险优先数的航空发动机可靠性设计方法

为了解决故障模式和影响分析难以融入航空发动机设计中的难题，提高可靠性水平，在型号研制工作中摸索出利用故障模式和影响分析中风险优先数的概念开展零部件某故障模式设计改进。运用风险优先数（RPN）的概念对设计故障模式和影响分析中严酷度和故障模式发生概率划分了1～10级评分原则，增加了故障被检测难度，且结合航空发动机特点，对故障被检测难度也划分了1～10级评分原则，得出了故障模式的风险优先数，确定了故障模式的优化排序，提出了确定风险改进项的方法。以某发动机的密封装置为例，利用严酷度、故障模式发生概率和故障被检测难度等级评分原则，得出了密封装置各故障模式风险优先数，确定了2项风险改进项。结果表明：利用严酷度、故障模式发生概率和故障被检测难度划分的1～10级评分原则进行风险优先数计算，可得出风险改进项，为提高发动机的可靠性水平提供了方向。

Aeroengine Reliability Design Method Based on Risk Priority Number

In order to solve the difficulty in integrating failure mode and effects analysis into aeroengine design， and improve productreliability， the concept of risk priority number in failure mode and effects analysis was explored to conduct component failure mode designimprovement during product R&D activities. Using the concept of risk priority number （RPN）， the severity and occurrence probability offailure mode were classified into 1-10 ranking criteria. The failure detection difficulty was added， and the 1-10 ranking criteria were alsoestablished for it considering the characteristics of aeroengine. The risk priority numbers of failure modes were obtained， the priority of thefailure modes was determined， and the method of determining risk improvement items was put forward. Taking the sealing device of anengine as an example， using the ranking criteria of severity， occurrence probability， and detection difficulty， the risk priority number ofeach failure mode of the sealing device was obtained， and two risk improvement items were determined. The results show that the risk prior?ity number calculated by using the 1-10 ranking criteria of severity， occurrence probability， and detection difficulty， can be used toobtain risk improvement items， which provides directions for improving engine reliability level.