径向支承刚度非对称转子系统振动特性分析

Analysis of Vibration Characteristics of Rotor System with Asymmetric Radial Support Stiffness

关键词:  支承刚度  刚度非对称  临界转速  不平衡响应  有限元

Key words:  Support stiffness  Asymmetric stiffness  Critical speed  Unbalanced response  Finite element method

摘要:

为研究径向支承刚度非对称对航空发动机转子系统的影响，采用集中参数模型和有限元理论建立此类转子振动特性的求解方法，研究关键影响参数及影响规律。结果表明：支承刚度非对称导致转子系统在两正交方向质量刚度特性不同，使稳态响应相位非同步变化和幅值差异，这是引发转子反进动涡动和椭圆形轴心轨迹的内在原因。增大支承刚度非对称程度使转子椭圆进动轨迹离心率增大，各阶临界转速单调变化；增大支承阻尼能有利于降低支承刚度非对称对转子响应幅值和进动状态的不利影响；利用ANSYS求解刚度非对称转子系统的多阶模态频率误差不大于0.3%，稳态响应峰值误差不大于0.96%，验证了利用ANSYS求解的可行性。

Abstract:

In order to study the effects of asymmetric radial support stiffness on the aero-engine rotor system， a solution method for vibration characteristic， key parameters and the influence of them were studied based on the lumped parameter model and 3D finite element method. The results show that the asymmetry of support stiffness causes the rotor system different mass and stiffness characteristics in the two orthogonal directions， and makes the asynchronous change of the steady-state response phase and the difference of the amplitude， which is the internal reason causing backward precession and oval axis orbit of the rotor system. When the asymmetry of the support stiffness increases， the elliptic eccentricity of the rotor’s axis orbit increases， and the critical speeds change monotonously. While increasing the support damping， the adverse effect of the asymmetry of support stiffness on the rotor’s response amplitude and precession state is reduced. The relative error of several modal frequencies of the rotor system with asymmetric support stiffness obtained by ANSYS is less than 0.3%， and that of the peak amplitude of steady-state response is less than 0.96%， which verifies the feasibility of ANSYS.