基础柔性的转子系统振动模态分析

Vibration Modal Analysis of Rotor System Based on Flexible Foundation

目的研究温度变化对基础柔性的双盘非对称转子系统振动模态的影响,为今后进一步研究转子系统的不平衡响应、碰摩故障分析、分叉与混沌行为和稳定性等动力学特征提供重要的基础性工作.方法利用有限元分析基本理论,建立转子系统的有限元模型,采用ANSYS弹线性结构分析软件,来分析转子系统的振动模态.结果结果表明,温度对转子系统的固有频率有一定的影响,各阶固有频率随温度的升高而降低;固有频率越大,温度越高,温度对转子系统固有频率的影响就越大;转子系统的1～8低阶振动模态主要是转轴的弯曲振动,9阶以上模态主要是转轴的弯曲振动和基础的弯扭组合振动的耦合;当温度超过600℃时,3～4阶、6～7阶和高于8阶固有频率频段内固有频率的相对降低程度变化较大.结论温度对转子系统固有频率的影响在温度变化较高的情况下不可忽略,基础柔性主要对高阶振动模态有影响.

In order to provide important basic work for the future study in rotor system on unbalance response ,rubbing fault analysis, bifurcation and chaos behavior and stability of the dynamic characteristics, etc, the effect of temperature variation on the vibration mode of double disk asymmetric rotor system considering foundation stiffness is analyzed. Using the basic theory of the finite element analysis, the finite element model of the rotor system is established, and the vibration model with ANSYS bomb linear structure analysis software in rotor system is analyzed. The analysis results show that as follows：The first,it is a certain effect of temperature variation on natural frequency in rotor system and all order natural frequency will reduce with the temperature power-up. The second, the larger natural frequency is and the higher the temperature is, the greater effect of temperature variation is on natural frequency in rotor system. The 1st to 8th order vibration mode in rotor system is mainly the bending vibration of spindle and more than 9th order mode is mainly the bending vibration of spindle coupling with the basis of combined bending and twisting vibration. The Last,when the temperature is over,in the 3rd to 4th,6th to 7th and more than 8th order natural frequency in the frequency range relatively reducing degree change greatly. When the temperature changes greatly, the influ- ence of the natural frequency in rotor system on temperature cannot be ignored, the flexible foundation mainly affects the high order vibration mode.