Theoretical Analysis and Design of Magnetostrictive Lamb Wave Detection

Conventional piezoelectric transducers suffer from stringent coupling demands and poor environmental robustness, limiting their utility for defect detection in the flat steel of down conductors in grounding grids. To overcome this, this study presents a Lamb wave excitation source based on magnetostriction. A mechanism model of the excitation source is established by analyzing the coupling among coil-driven electromagnetic excitation, magnetostrictive deformation, mechanical loading, and Lamb wave propagation in flat steel. The excitation source configuration and magnetization scheme are designed according to the geometric features of the down conductor. The experimental results show that, under pulsed current excitation, the magnetostrictive material produces a transient mechanical response, injecting disturbances into the flat steel and thereby enabling Lamb wave detection. The proposed source is compact and robust, showing strong potential for field applications. This study provides a novel active guided-wave solution for defect detection in the flat steel of down conductors and lays a foundation for subsequent signal analysis and engineering practice.