Experimental Study of Structural Health Monitoring for Pipeline Flange Based on Electromechanical Impedance
基于机电阻抗技术的管道法兰结构健康监测实验研究

A new type of piezoelectric composite fiber material, named as MFC (Macro-fiber composite), was adopted to monitor the working condition of bolt installed on flange at pipe connection based on electromechanical impedance method. Firstly, the effect of torque applied to bolt on impedance curves of host structure was experimentally investigated. At the beginning of torque application to bolt, the received impedance curve changes obviousely. After the applied torque increases to a certain extent, the change of impedance becomes mild. Furthermore, the relation between number of loosed bolt and the change of impedance curves received on the pipeline flange was also investigated. It is found that the damage index values of pipe structure increase linearly along with the increase of loosed bolt number. Root mean square deviation algorithm was used to effectively analyze and process the impedance values of pipe flange obtained under different working conditions. Therefore, it is easily concluded that electromechanical impedance-based method combining MFC as piezoelectric sensing element can be applied for health monitoring of flange in pipe structure and has good stability and potential application.