Preisach modeling of hysteresis in Terfenol

Terfenol (Tb0.3Dy0.7Fe1.9) and related materials have proven useful as electromechanical transducers. As with other transducers, these materials exhibit hysteresis, which must be included in any model of the transducer. Preisach theory is one of the available models that includes the effects of hysteresis. The theory is able to include the hysteresis by maintaining a history of the field reversals in the material. Both the strain and magnetization hysteresis loops in a 3.8-cm-diam Terfenol rod have been measured under 20.7-MPa longitudinal stress. The data has been used to derive a Preisach model of the rod, including hysteresis effects. It is possible to predict the strain and magnetization of the rod, including minor loops, with about 10%–15% accuracy.