艏摇运动下船用转子系统的非线性动力学特性

Nonlinear Dynamics of Marine Rotor-Bearing System Under Yawing Motion

考虑艏摇运动,基于短轴承油膜力理论建立了船用转子-轴承系统的动力学模型,理论分析显示系统运动微分方程具有较强的几何非线性。受到艏摇运动影响,转子会相对轴瓦产生偏转,受到非线性油膜力矩等多种作用力。采用数值方法,分析了艏摇运动影响下转子的非线性动力学特性及其相对轴瓦产生的偏转运动,研究了艏摇幅值及频率比对转子运动的影响。结果表明:当转速较低时,转子相对轴瓦产生的偏转较大;当转速较高时,艏摇使得转子能够进入混沌运动状态。转子振幅及其相对轴瓦的偏转随着艏摇幅值的增大而增大。随着频率比的减小,艏摇运动对转子影响逐渐减弱。

The dynamic model of the marine rotor-bearing system is developed on the short bearing theory af⁃ter considering the yawing motion,which shows that the differential equations are of strong geometric nonlin⁃earity.Due to the influence of yawing motion,the rotor will deflect relative to the bearing bush and be sub⁃jected to various forces such as nonlinear oil film moment.The nonlinear dynamic characteristics of the rotor system under yawing motion and the deflection motion are analyzed by numerical method.The influence of yawing amplitude and frequency ratio on the rotor motion is also studied.The results show that the rotor am⁃plitude and deflection relative to the bearing bush are large at low speeds.And at high ones,the yawing mo⁃tion causes the rotor to produce the chaotic oscillation.The amplitude of rotor and its deflection increase with the amplitude of yawing.With the decrease of the frequency ratio,the influence of yawing on the rotor gradu⁃ally weakens.