A numerical model of displacement for giant magnetostrictive actuator

A numerical model of displacement for a giant magnetostrictive actuator was founded. According to the model and the measured magnetic characteristic of giant magnetostrictive material, the relation between input current and output displacement for the actuator was calculated by means of the finite element method. A comparison between the calculating result and experimental one for the actuator was carried out and it was found that they were in agreement well. This demonstrates that the numerical model can be used for the design of giant magnetostrictive actuators.

I. Introduction

Magnetostricion is a coupled magneto-mechanical phenomenon: the presence of a magnetic field produces an important deformation or Young's modulus (direct effect), and the application of a stress modifies the magnetic properties: the magnetization curve or the hysteresis loop (inverse effect), which appears in all magnetic materials [1]. But they are very small in ordinary magnetic materials, for example, their magnetostrictive coefficient (the relative change in length of the material) only has the order of or , so these materials' applications are still limited. However, the rare-earth iron giant magnetostrictive materials' magnetostrictive coefficient exhibits of the order of , which allows to develop electromagnetic devices such as sonar, actuator, and magnetic sensor, so it opens new fields of application. Fig. 1. Schematic diagram giant magnetostrictive actuator