Modeling Magnetostrictive Transducers for Structural Health Monitoring: Ultrasonic Guided Wave Generation and Reception

Abstract

Ultrasonic guided waves provide unique capabilities for the structural health monitoring of plate-like structures. They can detect and locate various types of material degradation through the interaction of shear-horizontal (SH) waves and Lamb waves with the material. Magnetostrictive transducers (MSTs) can be used to generate and receive both SH and Lamb waves and yet their characteristics have not been thoroughly studied, certainly not on par with piezoelectric transducers. A series of multiphysics simulations of the MST/plate system is conducted to investigate the characteristics of MSTs that affect guided wave generation and reception. The results are presented in the vein of showing the flexibility that MSTs provide for guided waves in a diverse range of applications. In addition to studying characteristics of the MST components (i.e., the magnetostrictive layer, meander electric coil, and biased magnetic field), single-sided and double-sided MSTs are compared for preferential wave mode generation. The wave mode control principle is based on the activation line for phase velocity dispersion curves, whose slope is the wavelength, which is dictated by the meander coil spacing. A double-sided MST with in-phase signals preferentially excites symmetric SH and Lamb modes, while a double-sided MST with out-of-phase signals preferentially excites antisymmetric SH and Lamb modes. All attempted single-mode actuations with double-sided MSTs were successful, with the SH3 mode actuated at 922 kHz in a 6-mm-thick plate being the highest frequency. Additionally, the results show that increasing the number of turns in the meander coil enhances the sensitivity of the MST as a receiver and substantially reduces the frequency bandwidth.

Development and Prospect of Smart Materials and Structures for Aerospace Sensing Systems and Applications

“…It is a compact omnidirectional shear horizontal (SH) wave MPT that only needs two annular plaques to generate a specific SH1 mode detecting wave. Although both have long-range non-structural testing capabilities, the practice of structural health monitoring using guided waves relies more on Lamb waves than SH waves since Lamb waves are simpler to produce in actual engineering structures [ 132 ]. Subsequently, Lee et al [ 133 ] proposed a MPT with an axisymmetric configuration to generate omnidirectional Lamb waves and studied the generation mechanism and frequency characteristics of Lamb waves.…”

“…In order to overcome such problems, Xie et al [ 134 ] proposed a new MPT consisting of alloy patches and double-layer flexible printed circuits, which can be used for health monitoring of thin-walled structures with curved surfaces. Sha et al [ 132 ] established a multiphysics finite element model of on-board magnetostrictive transducers and studied the design variables and structures required for magnetostrictive transducers for structural health monitoring.…”

Combining ultrasonic guided wave and low-frequency electromagnetic technology for defect detection in high-temperature Cr–Ni alloy furnace tubes

“…Magnetostrictive ultrasonic guided wave inspection is a widely used technique for inspecting and monitoring plates and pipes 19 – 21 . In this furnace pipe inspection experiment, we employed the magnetostrictive ultrasonic guided wave detector model MsSR 3030R.…”

Flaw Detection in Highly Scattering Materials Using a Simple Ultrasonic Sensor Employing Adaptive Template Matching

“…The well-known ultrasonic pulse-echo method, first proposed by Pellam and Galt [ 1 ], is based on the important property of ultrasound that the ultrasonic pulse signal can be reflected at inhomogeneities and discontinuities in the material, and the reflected signal contains valuable information on the condition of the material or structure. Based on this simple property of ultrasound, great advances have been made both in ultrasonic sensor technology [ 2 , 3 , 4 , 5 ] and related NDT methodologies [ 6 , 7 , 8 ]. Embedded ultrasonic sensors are also widely used as an effective tool for structural health monitoring (SHM) purposes [ 9 , 10 ].…”