具有弹性支承的裂纹转子的动力特性分析

Analysis of the Dynamic Behavior of a Cracked Rotor with Elastic Bearings

推导了具有弹性支承偏置裂纹转子的运动微分方程。通过数值求解,得到了具有弹性支承偏置裂纹转子的盘心位移响应、支承处加速度响应。研究结果表明:具有弹性支承的裂纹转子系统在支承处加速度响应中也包含1X、2X、3X…频率成分,并且出现分数次共振现象;当裂纹转子以超临界转速运行时,支承处加速度响应的幅频图上2X以上各谐波分量仍明显存在。因而,转子以超临界转速或亚临界转速运行时,2倍频分量均可作为裂纹故障的重要特征。这对利用轴承座处的振动信号进行裂纹故障检测有一定的实用价值。

The motion equations of a cracked rotor supported on elastic bearings is derived in this paper. Adopting an accurate stiffness mold of a cracked shaft, its dynamical behaviors are analyzed by numerical method. Response of disc, acceleration response of bearings, and the influence of bearing stiffness on the response of system are investigated. The acceleration response of bearings contain 1X, 2X, 3X-..components, and the 2X, 3X...component achieves its maximum value respectively when ~ = 1/2, 1/3 The components of high frequency almost disappear in the response of the vibration of disc when the rotor runs in the supercritical region. But the components of high frequency exist apparently in the acceleration response of bearings when the rotor runs in the supercritical region. So the 2X component of tile acceleration response of bearings can be regarded as an evidence of the existence of crack. This conclusion is very useful for crack detection by the response of bearings.