The fundamental shear horizontal (SH0) wave-mode in plates and the torsional mode T(0,1) in pipe-like structures are extensively used in guided wave inspection. Different Electromagnetic Acoustic Transducer (EMAT) configurations can be employed: Lorentz force Periodic Permanent Magnet (PPM) or magnetostrictive EMATs, directly applied on the sample or with a bonded strip of highly magnetostrictive material on the structure. This work compares the performance of these solutions on steel plates. The analysis shows that magnetostrictive EMATs directly applied on steel plates have comparatively poor performance, while large signal amplitudes can be achieved when a layer of highly magnetostrictive material is attached on the structure. PPM EMATs generate intermediate wave amplitudes while being non-contact.

Topics
Electromagnetic acoustic transducer, Waveguides, Electrostatics, Elastic waves, Smart materials, Educational assessment
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© 2012 American Institute of Physics.
2012
American Institute of Physics
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