The giant magnetostrictive material, of which maximum strain is very large has been useful for many applications. That material has characteristics of large 'd constant', low Young's modulus and low mechanical quality factor. But magnetostriction and magnetization of the material have large hysteresis, so it seems that above mentioned characteristics are depend on the amplitude of exciting magnetic field. That is the reason of necessity of intellectual and complex design for the practical useful application.
In this paper, we explained the electric equivalent circuit of giant magnetostrictive vibrator at first. Next, we calculated exciting current dependency of the lumped parameters for the equivalent circuit based on measured impedance data of our developed vibrator, and also derived simple empirical equations of the parameters as a function of input current into the exciting solenoid coil.
From these results, it was clarified that larger 'd constant' and higher elasticity can be realized by larger magnetic field into the magnetostrictive rod along the axial direction. Electro-mechanical coupling factor and electro-mechanical efficiency of the vibrator reached to large values, 76% and 90.7% respectively when the input current is 1 ampere.
After all, it was verified that the developed vibrator is designed under adequate and excellent combination of magnetic bias and pre-stress.
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