Modeling of a Galfenol transducer using the bidirectionally coupled magnetoelasticmodel

Abstract

The bidirectionally coupled magnetoelastic model (BCMEM) developed by Mudivarthi et al (2008 Smart Mater. Struct. 17 035005) has been extended to include electriccurrents in its magnetic finite element formulation. This enables the model tocapture the magnetoelastic behavior of magnetostrictive materials subjected toelastic stresses and magnetic fields applied not only using permanent magnetsbut also the current carrying coils often used in transducer applications. Thismodel was implemented by combining finite element solutions of mechanical andmagnetic boundary value problems using COMSOL Multiphysics 3.4 (finiteelement modeling software) with an energy-based nonlinear magnetomechanicalconstitutive model. The coupling variables are magnetostriction and magneticpermeability, which are dependent on both the magnetic (magnetic flux density) andthe mechanical (stress) states of a magnetostrictive material. In this research,the BCMEM was used to simulate actuator load lines for a magnetostrictiveFe84Ga16 alloy, which were then compared with experimental data (Datta and Flatau 2008Proc. SPIE 6929 69291Z). Also, the ability of the BCMEM to capture theΔE effect in Galfenol was demonstrated. Finally, the use of the BCMEM as a tool fortransducer design optimization is demonstrated by using the model to visualizethe influence of different magnetic circuit designs on transducer performance.