Magnetostrictive Longitudinal Vibrators

摘要

This discussion will deal only with electromechanically-driven, resonant, devices used as underwater sound sources. Further, it will be limited to the design, properties, and advantages of vibrators having as active components, the magnetostrictive metals and their alloys. The magnetostrictive ceramic ferrites have been developed and examined in recent years, but, while they can be fabricated in useful shapes that are quite efficient as sources, as yet not type compares favorably with the piezoceramics in power capability or with the metals in mechanical strength. Particular attention will be given to the question of whether the change from almost exclusive use of magnetostrictive materials in the late forties to its practically complete exclusion in the mid-sixties is justified by performance. Another objective is to examine the potential use of feasible designs. Still another is to consider, in view of present needs, the desirability of further development of active materials. In approaching these purpose, we shall review the present situation and the history leading up to it. The advantages and disadvantages of magnetostrictive materials will be compared with other materials used for like purposes. Also included will be a cursory judgment of the chances for a successful result from efforts to improve the materials. (Author)