一种新的转子碰摩故障诊断特征的研究

建立Jeffcott碰摩转子的弯扭耦合振动非线性微分方程，通过数值仿真手段，着重分析转子碰摩故障的扭振时频域特点及其非线性振动特性，并描述动静间隙对碰摩转子扭振非线性特性的影响。研究表明，转子碰摩激起丰富的扭振频谱信息，主要包括N/2X、N/3X等分频成分以及1X、2X等倍频成分，且分频幅值往往比倍频大许多。在一定转速范围内，周期运动与复杂的非线性运动交替出现。而动静间隙对转子扭振特性影响明显，动静间隙越小，转子动静碰摩越严重，频谱成分越丰富，运动形式更趋复杂，相应的各复杂运动区的范围也越宽。文中揭示的扭振特征为转子碰摩的状态识别与诊断提供了一种新方法。

RESEARCH OF A NEW CHARACTERISTIC FOR FAULT DIAGNOSIS OF RUB-IMPACT ROTOR

The nonlinear differential equations of coupled lateral and torsional vibrations of a rubbing rotor was established. Through numerical simulation, the feature of time-domain and frequency-domain and non-linear motion characteristics of torsional vibration were mainly analyzed. And the influences of clearance between rotor and stator on torsional vibration were studied too. The results show that abundant frequency of torsional vibration is excited by rotor rubbing, which is mainly composed of N/2X, N/3X sub-harmonic and 1 X, 2X super-harmonic components. The amplitude of sub-harmonic is usually larger than that of super-harmonic. Periodic motion and complex non-linear motion show in an alternant way. Torsional vibration is strongly influenced by clearance. Smaller the clearance is, the more serious the rub-impact is, the more complex the rotor motion is, and the more wider the range of motion zone is. Torsional vibration characteristics revealed in this paper supplies a new approach for the condition monitoring and diagnostics of rotor system.