航空发动机振动应力测量的贴片可靠性及优化分析

Reliability and Optimization Analysis of Strain-Gauge

关键词:  航空发动机  振动测量  贴片方案  可靠性  寻优准则

Key words:  Aero-engine  Vibration measurements  Strain-gauge application  Reliability  Optimum criterion

摘要:

为了评估航空发动机应变片粘贴误差对振动应力测量结果的影响程度，利用有限元计算与蒙特卡洛分析方法对压气机转子叶片的贴片方案进行了研究，并提出基于可靠度的贴片方案优化准则。分析结果表明:当贴片位置由应变梯度较小的B点移动至应变梯度较大的A点时，相对应变误差增加了0.5倍，贴片可靠度降低了0.3倍；当贴片方向与最大主应变方向之间的夹角由0°增加至30°时，相对应变误差增大了0.6倍，贴片可靠度降低了0.4倍；根据可靠度准则，所选贴片方案可同时对两阶模态的振动应力进行有效测量，其可靠度达到限制值0.9以上，表明将该准则用于贴片方案寻优是合适的。

Abstract:

The strain-gauge application schemes were investigated through finite element analysis and Monte Carlo simulation methods，so as to evaluate the impact of sensor placement tolerances on vibratory response during aero-engine vibration test. The strain-gauge application scheme optimum criterion was put forward based on reliability theory. The analysis results show that when the strain-gauge was placed from point B to point A，because of the raising of strain gradient，the relative strain error increased by 0.5 times，and the reliability of the scheme was decreased by 0.3 times. When the angle between strain-gauge placement orientation and maximum principle strain orientation was expanded from 0° to 30°，the relative strain error increased by 0.6 times，while the reliability of the scheme was decreased by 0.4 times. According to the reliability criterion，the selected strain-gauge application scheme could effectively measure the vibration stress of two modes simultaneously，and it’s reliability exceeded the limit value of 0.9. The research indicates that it is adequate to use the reliability criterion for the strain-gauge application scheme optimization.