Nan Guofang, Zhang Yang, Zhu Yujie, Guo Wei
University of Shanghai for Science and Technology, Shanghai, P.R. China.
Sci Prog. 2020 Jul-Sep;103(3):36850420944092. doi: 10.1177/0036850420944092.
A new nonlinear rotor model supported by the rolling bearing is established under the consideration of the bearing with waviness fault, the unbalanced excitation, the nonlinear Hertz contact force, the varying compliance vibration, and, especially, the physical nonlinear stiffness of the shaft material. The expression with cubic nonlinear terms is adopted to characterize the physical nonlinear stiffness of the shaft material, and the sinusoidal wave is applied to describe the shape characteristics of the waviness fault. The dynamic equations of motion for the new model are developed, and the calculation example of the rotor system supported by the bearing JIS6306 is solved by the variable step-size Runge-Kutta methods to study the effect of the waviness, the clearance, the mass eccentricity on the dynamic behavior. The research results show that growth of the amplitude for the waviness changes the energy distribution of the vibration process; the enlargement of bearing clearance will reduce the stability of the system; the increase in the number of the waviness will make the order of the frequency components changed; for the nonlinear stiffness bearing-rotor system with waviness fault, the augment of mass eccentricity will enhance the impact of the nonlinear stiffness on the system.
在考虑存在波纹度故障的轴承、不平衡激励、非线性赫兹接触力、变柔度振动，尤其是轴材料的物理非线性刚度的情况下，建立了一种由滚动轴承支承的新型非线性转子模型。采用含有三次非线性项的表达式来表征轴材料的物理非线性刚度，并应用正弦波来描述波纹度故障的形状特征。推导了新模型的动力学运动方程，并通过变步长龙格 - 库塔方法求解了由JIS6306轴承支承的转子系统的计算实例，以研究波纹度、间隙、质量偏心对动力学行为的影响。研究结果表明，波纹度幅值的增大改变了振动过程的能量分布；轴承间隙的增大将降低系统的稳定性；波纹度数量的增加会使频率成分的阶次发生变化；对于存在波纹度故障的非线性刚度轴承 - 转子系统，质量偏心的增大将增强非线性刚度对系统的影响。
