High-Performance Magnetostrictive Transducers

Abstract

This paper is directed to the use of magnetostrictive materials for the generation of high-intensity mechanical vibration, sound, and ultrasound. It will present a mathematical analysis of a novel method of electromagnetic polarization and excitation that affords previously unattainable combinations of peak-to-peak magnetostrictive strain energy, electromechanical efficiency, and linearity. The analysis is based on a nonlinear model valid for isotropic, square-law magnetostrictive materials. To achieve these results, electromagnetic excitation is applied at a large angle relative to the axes of static polarization and mechanical output. Because this is usually most conveniently achieved by application of magnetic vectors at right angles to one another, the method has been termed “orthogonal excitation.” A specific system for orthogonal excitation, which permits electromagnetic self-polarization, will also be discussed.