Modeling of a Terfenol-D ultrasonic transducer

A large variety of applications exist which take advantage of the high dynamic strain and high energy coupling factor exhibited by "giant" magnetostrictive materials. One such material is the rare earth-iron compound Terfenol-D (Tb0.3DY0.7Fe1.95), which is being increasingly used in industrial, biomedical and defense applications. In order to fully realize the performance of this material, it is necessary to accurately model magnetostrictive transducer behavior from DC through the low ultrasonic regimes where the material is used. This paper has been motivated by the need for physically-based performance models of magnetostrictive materials as used in transducers. To this end, a recent magnetoelastic model for magnetostrictive transducers is employed to characterize the magnetization and strain behavior of Terfenol-D at frequencies from 1 Hz to 30 kHz. Model simulations were compared to experimental measurements at various drive levels and frequencies of operation, both under magnetically unbiased and biased conditions. The model provides an accurate characterization of the magnetization and strain for all operating conditions studied. However, further progress in strain simulations may be achieved through improvements in minor loop closure techniques and additional parameter identification.