竞争风险模型下变环境的发动机叶片可靠性分析

针对航空发动机转子叶片的恶劣工况导致其存在多种故障模式,各种故障的失效与使用环境紧密关联,给航空发动机转子叶片的可靠性分析或风险控制带来了难度这一问题,从转子叶片的磨损和裂纹两种主要故障模式特点出发,研究了变环境下的转子叶片磨损故障模型和疲劳裂纹故障模型,提出了一种基于竞争风险模型的转子叶片可靠性分析方法,并给出了求解算法；以某高压涡轮转子叶片为例进行了分析研究.结果表明:在可靠性分析中采用单个故障模型比竞争风险模型风险更大；且在竞争风险模型下,如果不考虑推力环境的影响,以不可靠度要求0.1为例,相应风险增加了33%,验证了所提方法的实用性. 

Reliability analysis of engine blade under varied environment with competing risk model

The complicated working condition results in the existence of multiple failure modes in aero-engine blade,and the failure rate of those failures is closely related with the operating environment,so,it is difficult to analyze the reliability of engine blades and control its risk.To solve the problem,firstly,based on the characteristics of wear and thermal crack failure modes commonly existing in rotor blades,the wear and thermal crack failure models with variable environment were researched,respectively.Secondly,a reliability analysis method based on competing risk model for rotor blades was proposed,and the corresponding algorithm was given.Finally,a high pressure turbine (HPT) rotor blade was analyzed and studied as an example.And the result showed that the risk was higher under single failure model compared with the competing risk model.When the competing risk model was employed in the reliability analysis,if the impact of thrust was not considered,the risk increased by 33 ％ given the unreliability of 0.1,verifying the practicability of the proposed method.