Megahertz-range guided pure torsional wave transduction and experiments using a magnetostrictive transducer.

This work is concerned with high-frequency guided torsional wave experiments in the range of 1 to 2 MHz in a cylindrical waveguide. A specially configured meander coil-magnetostrictive patch transducer was developed and successful experimental results of generation and measurement of guided pure torsional waves of up to 2 MHz were achieved. The usefulness of the developed method was demonstrated through a case study to detect a small-sized crack which would be otherwise difficult to identify with a lower-frequency torsional wave.