非线性油膜力作用下转子弯扭耦合振动特性研究

On coupled bending and torsion of rotor with nonlinear oil-film force

建立了非线性油膜力作用下转子-轴承系统弯扭耦合振动的数学模型.采用Rugge-Kutta数值积分方法计算模拟了转子升速过程中弯曲振动和扭转振动的不平衡响应,得到了转子弯曲振动的三维谱图和分岔图.分析发现,转子的弯曲振动会发生倍周期和概周期等复杂的非线性动力学行为.通过与不考虑弯扭耦合作用的系统特性进行比较,指出在转子弯曲振动临界转速附近,弯扭耦合作用对转子弯曲振动特性影响最大.数值分析揭示了扭转振动随转速升高,振幅基本保持不变,频率减小,有助于更深入地认识转子-轴承系统的弯扭耦合振动特性.

A mathematical model of a rotor with nonlinear oil-film force was presented,in which coupled bending and torsion were considered.The unbalance response of the rotor was numerically calculated by Rugge-Kutta method,and the bifurcation diagrams and waterfall plot were obtained to analyze dynamic characteristics of the system.The results reveale multiform complex nonlinear dynamic behavior of the rotor,that comprises periodic,double periodic and quasi-periodic motion.By comparing with dynamic characteristic of the system without considering the interaction of bending and torsion,it shows that bending vibration is heavily affected by the interaction of bending and torsion when rotating speed is near by the critical speed.The numerical study illustrated characteristics of torsion with increasing rotating speed.The results can provide a deeper understanding to coupled bending and torsion of the rotor-bearing system.