针对基于磁致伸缩式纵向超声导波传感器的管道无损检测问题,介绍了磁致伸缩式纵向超声导波传感器的检测原理及其结构.在此基础上,对接收传感器与接收源之间的阻抗匹配问题进行了讨论,阐述了实现阻抗匹配的条件与方法,并且通过理论计算得到最佳匹配条件与匹配电路的最佳电容.最后,设计了验证试验,验证了阻抗匹配问题的存在,讨论了阻抗匹配角、匹配电容值与导波信号幅值之间的关系,并且利用试验方法得到了真实条件下匹配电路的最佳电容值.

Aiming at the problems of nondestructive testing of pipelines based on longitudinal guided wave magnetostrictive sensor,in this article,the testing principle and structure of the longitudinal guided wave magnetostrictive sensor was introduced.Based on it,the problem of the impedance matching between the receiving transducer and the receiving source was discussed deeply.The conditions of implementation and methods of impedance matching are elaborated.Optimal matching condition and the optimal capacitor of the matching circuit is obtained from theoretical calculations.Finally,experiment was designed to verify the existence of the problems of impedance matching,and the relationships among the impedance matching angle,the matching capacitance and the guided wave signal amplitude was discussed,and the best capacitance value of matching circuit under real conditions was obtained by experimental method.