偏心量对轴向碰摩系统弯扭耦合非线性振动特性影响的分析

对偏心量改变导致的轴向碰摩系统的弯扭耦合非线性振动特性的变化进行了初步研究。建立了转静子耦合系统计算模型,利用数值积分和Poincare映射方法,对转子系统由于轴向碰摩故障导致的非线性动力学行为进行了数值仿真研究,给出了系统响应随偏心量变化的分岔图和一些典型的Poincare截面图、相轨图、轴心轨迹、幅值谱图和时域响应等。研究结果表明:偏心量是激起碰摩的一个主要因素,且系统响应对偏心量的变化比较敏感,随偏心量的增加,系统的响应将呈复杂化;碰摩发生后,振动响应的主要成分为1/3、1/2、2/3和1倍频,但各成分的存在与否与偏心量大小有关,有时会导致高阶频率成分的出现;碰摩发生后时域波形和轴心轨迹有明显的改变;分岔图是判别系统是否碰摩的有效工具;转、静子的扭转振动响应,对碰摩的发生和消失表现得更为明晰和精确,且其特征也不同于已知的其它故障类别,尤其是静子机匣,故应用扭转振动特性来监测和诊断碰摩故障是可取的;依据单一的振动谱图分析系统的特征较为困难,甚至有可能误判,因此应结合几种谱图综合判断。

Nonlinear Characteristics of Axial Contact Rotor-Stator System with Coupled Bending and Torsion

A comprehensive rotor-stator axial contact model is well developed with the consideration of both rotor and stator dynamics.The governing equations of the system about rotor-stator axial contact are derived,where the nonlinearly coupled effect of bending and torsion vibration is taken into account.The numerical integration program is adopted to evaluate the system parameters,such as the bifurcation,poincare section map,trajectory of axes,phase trajectory,frequency spectrum time response.It is found that the eccentricity is the primary factor for the contact,the vibration response is sensitive to the eccentricity,and the system gets more complecated with the enhancng eccentricity.The torsion vibration response describe the contact occurring or vanishing more clearly and precisely,and the characteristics is different from another known malfunction,especially for stator.It is difficult to estimate the system characteristics by a single spetrogram,which motivates to synthesize several ones to diagnose.