转子—轴承系统阻尼与固有频率的理论计算

临界转速的计算是转子——轴承系统设计标准的重要组成部分,此外,还必须确定由轴承或其它因素所引起的稳定性。本文通过计算转子——轴承的系统阻尼和自振频率来同时解决上述两类问题。轴承及轴承外部的弹性与阻尼对系统稳定性的影响作了必要的研究,从而扩大了方法的使用范围。分析中考虑了陀螺力矩、剪切变形、轴承动特性诸因素的影响。利用复数变量基于传递矩阵法导出系统总矩阵。设计了计算机程序,计算中将已求得的复数共轭根从多项式中消除,从而缩短计算时间。本文建立的力学模型可模拟任何实际转子和轴承分布。为了验证方法和程序的可靠性对实际转子——轴承系统作了计算,并将其计算结果与实测结果作了比较。方法和计算机程序可作为高速转子——轴承系统设计的有力工具。

THEORETICAL CALCULATIONS OF DEMPING AND NATURAL FREQUENCY OFROTOR-BEARING SYSTEMS

An important part of the standard design procedure for a rotor-bearing system is the calculation of its critical speeds. Furthermore,have to determine whether a rotor-bearing sestem experience instability because of the journal bearings, or from other sources. This paper describes a computational method to solve both types of problems mentioned above simultaneously by means of calculations of demping and natural frequency of rotor-bearing systems. Nece- ssary equations are developed to study the effect of bearing as well as bearing support flexibility and damping on the system stability, thereby enhancing the applied range of the art. Included in the analysis are the effects of diks gyroscopic moments, shear deformation, and speed dependent bearing characte- ristics. The method of solution is based on the Transfer Matrix approach and uses complex variable notation to develop the overall system matrix. The ana- lysis has been programmed for digital computer solution. Computational time is saved by eliminating from the polyonmial the complex conjugates of the roots already found. Mechanical model established by this paper can simulate any practical shaft geometry and support configuration. To demonstrate the appli- cation and accuracy of the method and program, calculation results are shown for the practical rotor-bearing sestems and compared with experimental resuts. The program can be made one of the forceful means for design a rotor-bearing sestem with high speed.