Generation and Detection of Torsional Waves in a Rotating Shaft Using a Magnetostrictive Patch Array

A new magnetostrictive patch array transducer for the generation and detection of torsional waves is developed for the on-line health monitoring of rotating shafts. Even though the torsional wave is useful in nondestructive evaluation due to its non-dispersive property, a transducer generating torsional waves in rotating shafts has not been developed so far. In this research, a torsional wave transducer using the magnetostrictive effect is newly developed. By bonding an array of magnetostrictive rectangular patches on the outer surface of the shaft at an oblique angle of 45 degrees and encircling the array by a solenoid coil, we have successfully generated and measured torsional waves by the developed transducer. Several experiments were carried out to check the transducer performance.