无定心弹簧刚性转子—SFDB系统非同步稳态响应的稳定性分析

本文用谐波平衡法研究了无定心弹簧刚性转子—挤压油膜阻尼器轴承 (SFDB)系统的稳态响应和稳定性 ,其中通过二个耦合的二阶微分方程来近似模拟运动 ,非线性油膜力作用处的非同步稳态响应通过运动微分方程的周期解求得。本文建立了油膜力的等效线性化模型。提出了新的稳定性分析方法。利用导出的等效动力特性系数建立了稳定性分析的判据 ,证明满足此判据的稳态响应是稳定的。并以该系统的次谐波响应为例 ,比较了本方法与数值积分方法的计算结果

STABILITY ANALYSIS OF A RIGID ROTOR ON SFDB WITHOUT A CENTRALIZING SPRING

The stable nonsynchronous responses and the stability of motion of a rigid rotor supported on squeeze film damper bearings(SFDB)without a centralizing spring are studied by means of harmonic balance method.The motion of the system is approximately simulated by two coupled second order differential equations.The stable nonsynchronous response at the action point of nonlinear oil film force can be obtained from the periodic solution of the differential equations of motion.With the help of an equivalent linearized model of the oil film force,the equivalent dynamic characteristic coefficients corresponding to the determined motion of the original system are obtained.A new method to analyse the stability of the motion of the equivalent linearized system is put forward in detail according to the theory of small pertubation.It is quite interesting to point out that the derived criterion for the motion stability is simple in form and depends on the equivalent damping coefficients only.A system with 1/2 order subharmonic response is taken as an example to illustrate this method.The calculated results are compared with those of fourth order Runge Kutta method.It is shown that our method has the same accuracy of calculation,but gains an advantage in saving computing time.