Introduction of a balk Magnetostrictive Bending Actuator

In this paper a bulk bending magnetostrictive actuator using a cylindrical permendur rod is presented. By passing a magnetic field through a thin layer of a magnetostrictive rod, tensile deformation of the layer would cause bending of the rod. Generation of magneticfield in the thin layer of the material is carried out by coils and their comb shape magnetic core. The Comsol software is used to calculate the magnetic field passing through the material. After construction of the actuator, deflection values for different currents are measured and compared with the results of the simulation. Actuator has been tested under AC and DC signals. In order to increase the bending amplitude of the actuator, the excitation with the AC signal has been used at the resonance frequency of the actuator. Due to formationof eddy currents as the result of AC magnetic fields, the field penetration in the material would be less than that of the constant field. Therefore, tensile deformation would occur in a narrow layer of the rod which causes a larger bending deformation. Based on experimental results, the maximum displacement of the actuator in the DC mode by applying 3.8 A is about 1.6μm and inthe AC mode at the frequency of 130 Hz and excitation current of 3.8A is about 120μm.

Keywords:

Magnetostrictive , Permendur , Bulk Bending actuator