Study of villari effect and its application in sensors

Magnetostriction is the changing shape of ferromagnetic materials in the present of magnetic field. Magnetostriction has different effects that the most important effects are Joule and villari effects. Joule and Villari effects are kind of bidirectional energy exchange between magnetic and mechanical energies. Therefore these materials provide a mechanism both for actuation and sensing applications. Joule effect is used in actuators and villari effect use in sensors application. Terfenol-D is a giant magnetostrictive material that is alloy of ferrous, terbium and dysprosium. In order to measure the force, a magnetostrictive force sensor with Terfenol-D is presented. The design method of the Terfenol-D force sensor is expounded firstly. In the next step that theoretical and experimental study of villari effect is accomplished. A model is developed based on the coupled linear magnetomechanical constitutive equations. An experimental setup has been designed and fabricated for study. The optimal pre-load and bias magnetic field are studied through experiments. The paper presents a foundation for the development of magnetostrictive force sensor with Terfenol- D.

Keywords:

force sensor , Terfenol-D , villari effect , pre-load , magnetic bias