Review of magnetostrictive patch transducers and applications in ultrasonic nondestructive testing of waveguides

• Published in: Ultrasonics 2015-09, Vol.62, p.3-19
• Main Authors: Kim, Yoon Young, Kwon, Young Eui
• Format: Article
• Language: English
• Subjects: Magnetostrictive patch transducer; Ultrasonic non-destructive testing; Waveguides
• ISSN: 0041-624X; 1874-9968
• DOI: 10.1016/j.ultras.2015.05.015

•Today’s magnetostrictive patch transducer technology is reviewed.•Applications for ultrasonic nondestructive testing in waveguides are reviewed.•The operating principle, analysis and design of the transducer are covered.•The transducers developed for plates, shafts and pipes are presented.•Tailored transducers for metamaterial and phonon crystal waveguide are illustrated. A magnetostrictive patch transducer (MPT) is a transducer that exploits the magnetostrictive phenomena representing interactions between mechanical and magnetic fields in ferromagnetic materials. Since MPT technology was mainly developed and applied for nondestructive ultrasonic testing in waveguides such as pipes and plates, this paper will accordingly review advances of this technology in such a context. An MPT consists of a magnetic circuit composed of permanent magnets and coils, and a thin magnetostrictive patch that works as a sensing and actuating element which is bonded onto or coupled with a test waveguide. The configurations of the circuit and magnetostrictive patch therefore critically affect the performance of an MPT as well as the excited and measured wave modes in a waveguide. In this paper, a variety of state-of-the-art MPT configurations and their applications will be reviewed along with the working principle of this transducer type. The use of MPTs in wave experiments involving phononic crystals and elastic metamaterials is also briefly introduced.