非线性油膜力作用下多转子耦合系统的动力学特性研究

发布时间：2018-03-10 04:35

本文选题：非线性动力学　切入点：多转子系统　出处：《西安科技大学》2012年硕士论文　论文类型：学位论文

【摘要】：转子系统在机械、动力、航空和航天等领域有着广泛的应用，是机器设备的重要组成部分。因此研究在非线性油膜力作用下转子系统的振动特性对安全运行和状态监测具有重要意义。本文以具有轴承不对中的多跨转子系统为研究对象，阐述了不同非线性油膜力模型假设，研究了在不同参数下系统的非线性动力学特征，分析了系统的分叉图、时域图、频谱图以及庞加莱截面图，然后用实验来验证模型假设的合理性；最后以非线性油膜力作用下圆锥齿轮转子系统为研究对象，对圆锥齿轮转子系统进行数值分析，分析系统的分叉图、时域图、频谱图以及庞加莱截面图等来研究系统的非线性动力学特征。通过分析得到以下结论： 1、基于短轴承模型分析了柔性转子系统的动力学特性，结果表明：具有轻微的轴承不对中情况下，在转速较低时系统呈同步周期的运动，随着转速的增加，出现倍周期分叉。且在周期1、周期2和准周期间反复交替出现。而当采用长轴承模型时，在转速较低时系统的运动仍然为同步周期运动，即轴承不对中量对系统运动的影响并不明显。随着转速的增大，系统运动表现为准周期运动，且有跳跃到周期1的运动状态。 2、讨论了转子参数变化对系统非线性动力学特性的影响，重点研究了质量不对称和轴承不对中量对系统动力学行为的变化情况。结果显示，两边质量不对称时，随着转速的不断增加，系统转速的倍周期分叉较质量对称系统提前，且系统的运动出现了周期8运动。另外，随着转速的增大，不对中量对系统的运动状态的影响越明显。 3、对具有轴承不对中转子系统的动力学特性进行了实验研究，并将测试与数值分析结果进行了比较。结果显示实验和数值模拟得到的动力学行为例如轴心轨迹、频谱图相近，从而验证了上述力学模型的合理性。 4、研究了在不平衡质量和非线性油膜力作用下圆锥齿轮转子系统的非线性动力学特性。结果表明：在低转速时转子运动为周期1，此时转子的运动表现为不平衡响应；随着转速的增加，转子的振幅急剧增大，，当达到一定值时，转子直至碰到轴承内壁。
[Abstract]:Rotor systems are widely used in mechanical, power, aerospace and other fields. Therefore, it is important to study the vibration characteristics of rotor system under the action of nonlinear oil film force for safe operation and condition monitoring. In this paper, the multi-span rotor system with bearing misalignment is taken as the research object. The assumptions of different nonlinear oil film force models are expounded, the nonlinear dynamics characteristics of the system under different parameters are studied, and the bifurcation diagram, time domain diagram, spectrum diagram and Poincare sectional diagram of the system are analyzed. Finally, taking the bevel gear rotor system under the action of nonlinear oil film force as the research object, the numerical analysis of the bevel gear rotor system is carried out, and the bifurcation diagram and time domain diagram of the system are analyzed. The nonlinear dynamic characteristics of the system are studied by spectrum diagram and Poincare section. The following conclusions are obtained by analysis:. 1. Based on the short bearing model, the dynamic characteristics of the flexible rotor system are analyzed. The results show that under the condition of slight misalignment of the bearing, the system moves synchronously with the increase of the rotational speed when the rotational speed is low. Double period bifurcation appears. And it appears alternately during period 1, period 2 and quasi cycle. When the long bearing model is adopted, the motion of the system is still synchronous period motion at low rotational speed. With the increase of rotational speed, the motion of the system is quasi-periodic, and it has the state of jumping to period 1. 2. The influence of rotor parameters on the nonlinear dynamic characteristics of the system is discussed, and the variation of mass asymmetry and bearing misalignment on the dynamic behavior of the system is studied. The results show that when the mass on both sides is asymmetric, With the increasing of the rotational speed, the cycle doubling bifurcation of the system speed is earlier than that of the mass-symmetric system, and the motion of the system has a period of 8 motions. In addition, with the increase of the rotational speed, the effect of the non-alignment on the motion state of the system becomes more obvious. 3. The dynamic characteristics of the bearing non-transfer subsystem are studied experimentally, and the results of the test and numerical analysis are compared. The results show that the dynamic behavior obtained from the experiment and numerical simulation, such as the axis trajectory, is similar to the spectrum diagram. Therefore, the rationality of the above mechanical model is verified. 4. The nonlinear dynamic characteristics of the bevel gear rotor system under the action of unbalance mass and nonlinear oil film force are studied. The results show that the rotor motion is periodic 1 at low speed, and the rotor motion is unbalance response. With the increase of rotational speed, the amplitude of the rotor increases sharply. When the rotor reaches a certain value, the rotor encounters the inner wall of the bearing.
【学位授予单位】：西安科技大学
【学位级别】：硕士
【学位授予年份】：2012
【分类号】：TH113

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