Omnidirectional lamb waves by axisymmetrically-configured magnetostrictive patch transducer

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control Vol. 60; no. 9; pp. 1928 - 1934
• Main Authors: Lee, Joo Kyung, Kim, Hoe Woong, Kim, Yoon Young
• Format: Journal Article
• Language: English
• Published: United States IEEE 01.09.2013; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Coiling; Computer Simulation; Computer-Aided Design; Equipment Design; Equipment Failure Analysis; Ferroelectric materials; High-Energy Shock Waves; Investigations; Lamb waves; Magnetic fields; Magnetic resonance; Magnetics - instrumentation; Magnetostriction; Models, Theoretical; Plates; Scattering, Radiation; Shape; Sonication - instrumentation; Transducers; Vibration mode; Vibrations; Wavelengths
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2013.2777

This work presents the generation of omnidirectional Lamb waves by a new magnetostrictive patch transducer (MPT) and investigates its generation mechanism. Although MPTs have been widely used for wave transduction in plates and pipes, no investigation reports the generation of omnidirectional Lamb waves in a plate by an MPT. For the generation, we propose an axisymmetrically-configured MPT that installs multiple axisymmetric turns of coil outside of a permanent cylindrical magnet located above the center of a circular magnetostrictive patch. After confirming the omnidirectivity of the proposed MPT experimentally, the mechanism of the Lamb wave generation and its frequency characteristics are investigated. It is also shown that the Lamb wave is most efficiently generated in a test plate when its wavelength is equal to two-thirds of the magnetostrictive patch diameter. If this wavelength¿patch diameter relation holds, the second radial extensional vibration mode of the patch of the proposed MPT is shown to be the mode responsible for generating the Lamb wave in a plate.