含裂纹转轴系统的动态特性与实验研究

裂纹是转轴系统常见的一种故障形式,裂纹的呼吸效应会改变转轴的动态特性。为研究该呼吸效应的影响,提出一种含裂纹模块和无裂纹模块的组合建模方法,通过设置不同模块之间的接触属性实现裂纹缺陷的预置,分析了不同转速和不同裂纹深度条件下裂纹呼吸效应对转轴系统动态特性的影响;并采用可对转轴水平和竖直两个方向振动信息进行高效同步测量的新型单目视觉位感条纹振动测量方法开展了含裂纹转轴系统的动态特性实验研究。仿真与实验结果相吻合,结果表明:裂纹缺陷会导致转轴振动中出现倍频成分,当转速接近1/2临界转速时,2倍频信号非常明显,且其幅值大于转频幅值,同时随着裂纹深度由1 mm加深至5 mm,转轴的振动幅值增大了5倍,2倍频成分更显著。

Dynamic Characteristics and Experimental Research of Cracked Shaft System

Crack is a common fault of the shaft system,and the breathing effect of the crack will change the dynamic characteristics of the shaft.In order to study the influence of the breathing effect,a modular modeling method with crack component and no crack component is proposed.The crack is preset by setting the contact properties between different modules.The influence of crack breathing effect on the dynamic characteristics of the shaft system under different rotating speeds and different crack depths is studied.A new monocular visual displacement-sensitive fringe pattern vibration measurement system is used to study the dynamic characteristics of the cracked shaft,which can simultaneously measure the horizontal and vertical vibration information of the shaft.The simulation and experimental results are consistent,which shows that the crack defect will cause the high frequency multiplication component in the shaft vibration.When the speed is close to half of critical speed,the double frequency component is very obvious and its amplitude is greater than the amplitude of rotating frequency.At the same time,with the crack depth increasing from 1 mm to 5 mm,the vibration amplitude of shaft increases by 5 times,and the influence of double frequency component is more significant.