Core Loss Study of Different Structures of Terfenol-D Rods

Abstract

To efficiently use Terfenol-D rods, six of its structures were studied. Finite element analysis was used to estimate and
compare the hysteresis, eddy current, and coil resistance losses of the six Terfenol-D rods. The loss factors of the rods were
calculated and analyzed. Furthermore, three structures of Terfenol-D rods were manufactured, and the loss factors of the
rods were measured. The results showed that an untreated rod had the largest hysteresis and eddy current losses on the outer
diameter surface, and the overall hysteresis loss of the rod was the smallest. Compared with the untreated rod, the eddy
current and hysteresis losses on the outer diameter surface of sliced and slit rods reduced, the overall hysteresis loss of sliced
and slit rods increased, and the overall eddy current loss of sliced rods reduced; the hysteresis and eddy current losses on the
surface of the sliced rods were less than that of the slit rods, and the overall eddy current loss of the sliced rods was less than
that of the slit rods; moreover, the eddy current loss of each rod was larger than its hysteresis loss. The numerical calculation
values of the coil resistance loss basically agreed with the theoretical calculation values. The finite element simulation
calculation values of the loss factors of the Terfenol-D rods agreed with the experimental test values.