安装节刚度对发动机整机耦合振动的影响分析

以带机匣的航空发动机转子试验器为研究对象，建立了模拟实际发动机安装条件下试验器的整机有限元模型。对试验器进行了整机模态试验，并利用试验器的模态试验结果对有限元模型进行了修改和验证。在此基础上，仿真计算了自由安装边界、固定安装边界和不同安装节刚度的弹性安装边界的试验器前3阶固有频率和模态振型，通过定义转静耦合因子，研究了安装节刚度对试验器转子、静子耦合程度的影响。结果表明:模态振型的转子、静子耦合程度越高，安装条件对该阶模态影响越大，并且安装节刚度对转子、静子耦合程度影响是非线性的。由于实际大型涡扇发动机的在很多模态下均存在转子、静子耦合现象，因此安装节的刚度对转子、静子耦合作用的影响不容忽视，在有限元建模和仿真计算中需要仔细考虑。 

Analysis on effect of mount stiffness on whole engine coupling vibration

Using an aero-engine rotor tester with casing, a finite element model of engine to simulate the actual mounting condition was built. The modal tests of the tester under installation were carried out, and the finite element model was updated and verified based on the modal test results. The first 3 order natural frequencies and modal shapes of the tester were calculated under the conditions of the free boundary, fixed boundary and flexible mounting boundary with different mount stiffness values. By defining a rotor-stator coupling factor, the effect of the mount stiffness on the coupling degree between the stator and the rotor was studied. Results show that the coupling degree between stator and rotor increases with the increasing effect of mounting condition for a certain order mode. Moreover, the effect of the mount stiffness values on the rotor-stator coupling is nonlinear. Because the coupling phenomena between stator and rotor exist in many modes of practical large scale turbofan engines, the effect of the mount stiffness values on the coupling vibration of engine cannot be ignored. Therefore, the mount conditions should be considered carefully in finite element modeling and simulating.