Experimental Study and Modelling of the Blocked Force of Terfenol-D Actuator

Terfenol-D is widely used in magnetostrictive actuators due to capability of applying mechanical forces in large values of magnitude and frequency. Dependency of structural coefficients of Terfenol-D on magnetic field intensity and losses of magnetic energy make it complicated to predict the value of actuator’s output force. In this paper, an experimental-theoretical model is presented to predict blocked force of the actuator at different operational conditions. Initially, a linear model for DC magnetic filed and an improved model introducing an energy efficiency coefficient for AC magnetic filed are proposed. The energy efficiency coefficient is obtained based on experimental power relations for hysteresis, eddy currents and excess power losses. An experimental setup is used to obtain stress-strain behavior of the actuator to extract the structural coefficients of the proposed model and an experimental relation is governed to predict the coefficients at different values of magnetic field. The proposed model contains power relations of amplitude and frequency of electrical current passing through the actuator which makes it possible to calculate blocked force at frequency range of 0-400 Hz. Obtained results of the model are validated by comparing to experimental results and the small values of errors show the model’s precision.