双重失效模式下民用航空发动机高压涡轮叶片报废特性与可靠性分析

Analysis of scrapping characteristics and reliability of civil aero engine high pressure turbine blade in dual failure modes

基于某型民用航空发动机下发后观测涡轮叶片报废状态的双重失效模式,计算了高压涡轮(HPT)叶片由自新使用循环数(CSN)引起的报废率。并结合疲劳损伤累积理论,探究了叶片报废率与失效分布函数之间的关系,得到了涡轮叶片失效分布与寿命期望的计算方法。基于大量涡轮叶片的观测数据,拟合出涡轮叶片按CSN计的失效分布,研究发现:某型民用航空发动机在成熟期内,第1级高压涡轮叶片失效规律服从指数分布,而第2级服从可靠性统计中不常见的指数-指数分布。

The scrapping rate of high pressure turbine(HPT)blades varying with cycles since new(CSN)was calculated in the dual failure modes,and the scrapping of HPT blades was observed after engine removal from wings.The relationship between scrapping rate and failure distribution of HPT blades was proposed in accordance with the theory of fatigue damage accumulation so that the failure distribution and life expectation of blades was obtained.Based on the proposal above and a large number of HPT blade maintenance data of a type of civil aero engine,the failure distribution function of HPT blades was fitted with CSN increasing.It was found that the failure of the Stage 1 HPT Blades of this type of aero engine was subject to exponential distribution,and the failure of Stage 2 HPT Blades subject to uncommon exponential-exponential distribution in the current reliability statistics.