航空发动机测量耙裂纹故障诊断

Crack Diagnosis of Aero-engine Rake

以航空发动机测量耙振动试验过程中的安全监测为需求。首先,基于测量耙结构特征简化模型,建立了含裂纹测量耙振动特征方程;其次,建立了某型测量耙有限元模型,通过数值模拟分析了裂纹参数(相对位置、裂纹长度)对测量耙固有频率的影响规律;最后,开展了该型测量耙的振动试验。扫频试验结果验证了测量耙有限元模型的准确性,测量耙在振动耐久性试验过程中出现孔边裂纹,固有频率降低了11.1%,表明在测量耙研制过程中开展振动考核试验时,可在试验现场通过试验前后固有频率的变化实时监测耙体的结构损伤。

This paper takes the safety monitoring in the process of vibration test of aero-engine rake as the demand traction.Firstly,based on the simplified model of rake structure characteristics,the vibration characteristic equation of cracked rake is established.Secondly,a finite element model of rake is established,and the influence of crack parameters(such as position,crack length)on the natural frequency of the rake is analyzed by numerical simulation.Finally,the vibration test of this type of rake is carried out.The results of the frequency sweep test verify the accuracy of the finite element model of the rake.During the vibration durability test of the rake,a hole-edge crack appears and the natural frequency is reduced by 11.1%.The results show that when the vibration assessment test is carried out during the development of the rake,the structural damage of the rake body can be monitored in real time at the test site through the change of the natural frequency before and after the test.