基于压电阻抗法的机械螺栓组松动监测及识别

Monitoring and Localization of Loosened Bolts Based on E/M Impedance Method

基于压电阻抗方法的结构健康监测(SHM)方法因其潜在的实用性而成为健康监测领域内重点研究的方法之一。介绍了压电阻抗技术用于结构健康监测的技术原理,分析了几种用于机械螺栓松动监测和识别方法的特点。实验以大型起重机等工程结构中常见的螺栓组为对象,通过HP4395A网络频谱阻抗分析仪测量粘贴在螺栓附近适当位置上的PZT压电片的阻抗特性,探讨了合适的扫描频率。分析了用均方根值(RMSD)作为损伤系数能实现对螺栓松紧程度的识别,而通过分布式的PZT能实现对螺栓组中螺栓松动的基本定位。

The electro-mechanical impedance method becomes the focus of the structure health monitoring（SHM） research because of its potential for application.The basic theory of structure health monitoring using the electro-mechanical impedance method is presents.When the piezoelectric sensor is coupled with the structure,the impedance spectrum which contains the change of structure mechanical impedance can be obtained with the help of impedance analyzer.When taking the bolts component on two thick plates as the research object,it is observed that the impedance peak will be shifted and changed when the torque value changed.With the algorithm of RMSD,the loosen condition of the bolts can be assessed.The appropriate frequency range for bolt looseness is also discussed.With the distributed PZTs,it’s possible to localize which bolt of the component is loosened.