Abstract:

A mathematical model with nonlinear oil film force was employed to study the pedestal looseness fault at two supports in a rotor-bearing system. By using Runge-Kutta numerical method, the motion equations were solved, and frequency characteristics of the rotor system was obtained after applying Fast Fourier Transformation(FFT) on these stable solutions. The simulation results show that when the vibration displacement is smaller than the maximum inner-space value, there are many low frequencies; when the vibration displacement is larger than the maximum inner-space value, there exist some apparent high frequencies. The simulation results will be helpful to diagnose the fault of pedestal looseness in this system.

Key words: pedestal, rotor, looseness, frequency characteristic, numerical simulation

摘要：

针对转子-轴承系统中两端支座发生的松动故障，建立了带有非线性油膜力的数学模型。采用数值仿真的方法对发生故障的转子系统进行模拟，得到了系统的频率特性。模拟结果表明：当支座发生松动振动时，若振动位移小于最大间隙值，则它的频谱除了1倍频分量外还有丰富的且相对幅值较大的低频成分；若振动位移大于最大间隙值，则它的频谱会出现非常突出的较高倍频的分量， 而1倍频却消失了。得出的结论有助于对该类故障的诊断分析。

关键词: 支座, 转子, 松动故障, 频率特性, 数值仿真