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Nonstationary Vibrations of a Rotating Machinery Through Critical Speeds and Active Damping

旋转机械在临界速度和主动阻尼下的非平稳振动

基本信息

批准号：
01550206
负责人：
ISHIDA Yukio
金额：
$ 1.28万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

项目摘要

Rotating machinery has nonlinear spring characteristics for various reasons. In this research, nonstationary oscillations through critical speeds caused by nonlinear spring characteristics are investigated.1. In an experimental apparatus in which a rotor was mounted on an elastic shaft, various kinds of subharmonic and summed-and-differential harmonic oscillations are observed.2. In the theoretical and experimental analyses, we originated Complex-FFT method which utilizes a digital signal processing technique. By using Complex-FFT method, phase plane analyses, and the asymptotic methods, the following results are obtained : (1) In the case of the major critical speed, the maximum amplitude gamma max in nonstationary oscillation has only one value for a given angular acceleration. The rotor can pass the critical speed when the acceleration is higher than a certain value. The bigger the acceleration, the smaller the maximum amplitudes. (2) In the case of subharmonic oscillation of order 1/2, the maximum amplitude gamma max varies between 0 and (gamma max)_1 in randam even if the angular acceleration is the same. (3) In the case of summed-and-differential harmonic oscillation caused by unsymmetrical nonlinearity, the maximum amplitude gamma max varies between two values (gamma max)_1 and (gamma max)_2 in random for a given angular acceleration. (4) In the case of subharmonic oscillation of order 1/3, the rotor can pass the critical speed if the value of accelaration is very small or very large. Otherwise, the nonstationary amplitude is drawn toward stationary amplytude and the rotor cannot pass the critical speed.3. The active damping technique is now under development and we could not obtain a completed results.

由于各种原因，旋转机械具有非线性弹簧特性。在本研究中，研究了非线性弹簧特性引起的临界速度下的非平稳振荡。在将转子安装在弹性轴上的实验装置中，观察到各种次谐波和和微分谐波振荡。在理论和实验分析中，我们提出了利用数字信号处理技术的Complex-FFT方法。通过复变fft方法、相平面分析和渐近方法，得到了以下结果：(1)在主要临界转速情况下，给定角加速度时，非平稳振荡的最大振幅gamma max只有一个值。当加速度大于某一值时，转子可以通过临界转速。加速度越大，最大振幅越小。(2)在1/2阶次谐波振荡情况下，即使角加速度相同，最大振幅gamma max在随机值0 ~ (gamma max)_1之间变化。(3)在非对称非线性引起的和微分谐振振荡中，对于给定的角加速度，最大振幅gamma max随机地在两个值（gamma max）_1和（gamma max）_2之间变化。(4)在1/3阶次谐波振荡情况下，如果加速度值很小或很大，转子都可以通过临界转速。否则，非平稳幅值向平稳幅值靠拢，转子不能通过临界转速。主动阻尼技术目前还在开发中，我们还不能得到一个完整的结果。