Design of Broadband Magnetostrictive Sheared Horizontal Guided Wave Transducer for Structural Health Monitoring

Abstract

In view of the defect that the magnetostrictive guided wave transducer with meander coil structure can only excite and receive the strong guided wave signal at a fixed frequency, a broadband magnetostrictive Sheared Horizontal (SH) guided wave transducer is designed for structural health monitoring of metal pipes and plates. This paper demonstrates the energy transfer mechanism of magnetostrictive SH guided wave transducer and proposes a type of transducer structure of small-width coil and magnetostrictive patch. Comparative experiments are conducted to study how magnetostrictive patch width and coil width influence the relationship between amplitude and frequency of guided wave signal of the transducer, and the transducer designed in this paper is used for the defect detection experiment. According to the experimental results, when the coil and the magnetostrictive patch are of the same width, the change of their width can notably influence the center frequency of the transducer, and the transducer can excite and receive SH guided waves with higher amplitude in a larger frequency range. The transducer designed in this paper can detect the defects with a smaller section loss rate by increasing the excitation frequency without changing the coil, which is more suitable for the structural health monitoring of industrial equipment.