Design of a magnetostrictive actuator considering magnetic bias and ohmic heat

Abstract

Magnetostrictive (MS) materials exhibit a large strain and a high energy-density, because of their large MS coupling coefficient. In particular, an MS actuator that uses Terfenol-D generates great-force and strain. The efficiency of an MS actuator is highly dependent on the pre-stress, magnetic field intensity, magnetic bias and thermal expansion. The specific type or shape of permanent magnet (PM) needed for a given magnetic bias is determined using numerical simulation. According to magnetic field the heat created by resistance influences the thermal expansion. This paper proposes the optimal exterior PM for achieving a magnetic bias and minimizing the ohmic heat effect with a geometric composite of an electromagnet considered to be a practically precise MS actuator.