变刚性支承转子的动力特性讨论

一、一种理想的转子稳态幅频线 一个转子如采用不同刚性的支承,则转子支承系统的幅频特性（r～ω）线不同。图1中虚线示出同一转子采用低刚性引和较高刚性K₂′支承时的幅频特性线1和2。有人想利用改变支承的方法来减小通过临界转速时的振动。方法是对图1（a）情况在转子角速度ω≤ω_Ⅰ时使支承刚性为k₂′,ω≥ω_Ⅰ时变支承刚性为K₁′;对图1（b）的情况则在ω≤ω_Ⅰ和ω_Ⅱ≤ω≤ω+Ⅲ支承刚性. 

DISCUSSION ON DYNAMIC CHARACTERISTICS OF A ROTOR WITH CHANGEABLE SUPPORT STIFFNESS

In this paper the author identifies that the rotor system will be nonlinear provided the support stiffness varies at ? with the amplitude unchanged and no external load is added to the support (it is difficult to add rotating load to it). Its amplitude-frequency curve must be obtained in accordance with the nonlinearvibration theorem. Although the maximum amplitude of the rotor system with nonlinear support stiffness may be decreased, it never follows the curve of solid line in Fig.l as the addition of two curves with different linear support stiffness. In order to demonstrate this argument, a brief analysis of the vibrationcharacteristics of a nonlinear rotor system is completed and its amplitude-frequencycurve is plotted in Fig.4.