Magnetostrictive Vibration Control Systems

Abstract

Results are presented summarizing dynamic per formance capabilities for three different magnetostrictive actuators with demonstration of magnetostriction used for control of struc tural vibrations in a beam. Project goals were to design a magne tostrictive actuator for use as a broadband vibration source (using magnetostriction for generation of dynamic forces), to fabricate a working prototype system, and to demonstrate magnetostrictive ac tuator use for vibration control. The vibration control work is modeled after analog proportional gain control techniques. A magnetostrictive actuator is used to oppose structural vibrations that are sensed with an accelerometer. The magnetostrictive ele ment of the actuator is permeated by a magnetic field that fluc tuates in direction at a rate proportional to the inverted accel erometer output. The resultant actuator strain is proportional in amplitude and 180° out of phase with the structure's vibratory mo tion. Use of a magnetostrictive actuator to reduce beam vibrations at frequencies up to 4000 Hz is shown. Also, broadband actuator frequency responses are shown that demonstrate practical imple mentation of magnetostrictive material in vibration generation systems which should carry over to use in vibration control ap plications at frequencies up to 10,000 Hz and above.