考虑非线性油膜力的裂纹转子动力学特性仿真

Simulation on Dynamic Characteristics of a Cracked Rotor Considering Nonlinear Oil Film Force

在考虑裂纹轴时变刚度和非线性油膜力的基础上,建立了含裂纹故障的双盘转子-轴承系统的动力学模型,采用数值积分方法对其求解,结合分岔图、轴心轨迹图、Poincaré截面图和三维谱图等,分析了转速、裂纹深度和不平衡对系统响应、分岔情况以及稳定性的影响.结果表明:该类系统出现了多周期、拟周期、混沌等丰富的非线性动力学行为;在裂纹较深的情况下,在较低转速便会发生倍周期分岔和多周期运动,系统的非线性和不稳定性增强;不平衡力的增大简化了系统的动力学行为,使系统失稳滞后,但不影响油膜振荡.

Considering the time varying stiffness and nonlinear oil film force, a dynamic model was established for the double disc rotor-bearing system with crack faults, and subsequently numerical integration method was used to solve the model, so as to study the effects of rotating speed, crack depth and unbalance force on the response, instability and bifurcation of the system by using bifurcation diagram, axis orbits, Poincar6 maps and cascade spectrum. Results show that when the rotating speed changes, rich non- linear dynamic behaviors would occur to the system, such as multiple periodic, quasi-periodic and chaotic motions. Under deep crack conditions, double period bifurcation and multi period motion would appear at a lower speed, when the system nonlinearity and instability tend to be enhanced. The increase of unbalance force simplifies the dynamic behavior of the system, makes the appearance of system instability lag behind, but does not affect the oil-whip.