Numerical Studies on Design of Terfenol-D Actuator using Coaxial Coils

Attaining a controlled output strain and utilizing a full potential of active material are the significant factors to design Terfenol-D actuator devises such as active damping devices, high speed hydraulic valve actuators, large-force linear motors and large torque rotating motors. To achieve this, a high magnetic biasing field is required in an actuator. The present work attempts to propose a suitable layout in a Terfenol-D actuator based on numerical magnetic field analysis. Three configurations namely single coil, coaxial coils and coil with permanent magnet combinations that surrounds the TerfenolD material are considered in the present study. Ansoft package magnetic flux density is used to evaluate the distribution of magnetic flux density of the layouts used in an actuator. Further, the magnetic flux density is evaluated and compared among them to decide the best configuration to be used in a Terfenol-D actuator. Structure and layout of a proposed actuator is outlined. With this, the number of turns required for coaxial coils is computed using Ampere’s law and in turn verified the same using the reluctance approach. Finally, it appears that all these results work as well as anticipated and has their individual advantages.