Wave selection using a magnetomechanical sensor in a solid cylinder

Magnetomechanical sensors have received much attention in recent years. However, investigations on the rejection of unwanted wave modes and thus the selection of a desired mode have not been reported. The purpose of this investigation is to present a technique to select only a desired wave mode in a solid ferromagnetic cylinder using a magnetomechanical sensor. To achieve this goal, we propose some bias magnet configurations for each of which either longitudinal or flexural waves alone can be extracted. A simplified theory relating bias magnet arrangement and measured wave modes is developed. Several experimental results confirm the validity of the present investigation.