EXAMINATION OF THE INTERACTION BETWEEN EDDY CURRENTS AND MAGNETOELASTICITY IN TERFENOL-D

When an electrically conducting magnetic material is magnetized dynamically, eddy currents will be induced inside the material. The eddy currents give rise to a decrease of the flux density obtained at quasistatic conditions at a specific magnetizing field and hence, for a magnetostrictive material such as Terfenol-D, also a decrease in the magnetostriction. Because of the magnetoelastic interaction in magnetostrictive materials, it is difficult to analytically predict the influence of these eddy currents. By solving the equation for the radial field distribution inside the rod numerically, a model which takes the eddy currents into account can be formulated. This radially resolved model makes it possible to calculate the local eddy current distribution inside the rod, and the rod, and by choosing the appropriate boundary conditions, the "effective" behavior of the rod can be calculated. Results obtained from a radially resolved model are compared with corresponding results from experiments. Also, a comparison is made between the radially resolved model and an analytical model for handling the influence of eddy currents in magnetostrictive materials.