Magnetostrictive actuators (MSAs) are electrical machines that use magnetostrictive cores (MSC), which deform in external magnetic fields. The bias magnetic field, necessary for the proper functioning of the MSC, may be produced by permanent magnets or by electric currents. In this paper the functioning of small size, simplified, linear, MSA is analyzed using numerical simulation. A bias winding is provided to ensure the necessary pre-magnetizing state, and a drive winding, both coaxial with the MSC made of Terfenol-D. The coils are powered by PWM, power sources. Voltage and current power sources are analyzed. The structural and electric eigenfrequencies of the MSA and its PWM source are analyzed as independent factors that concur to the electro-mechanical (displacement) of the MSA. Several conclusions, regarding the design of the MSA for optimal MSC yield are drawn.

Keywords: Magnetostriction, Magnetostrictive actuator, Terfenol-D, Pulse wide modulation (PWM) voltage excitation, PWM current excitation, Numerical simulation, Finite element