NONLINEAR FINITE-ELEMENT MODELING OF GIANT MAGNETOSTRICTION

Finite element modelling of giant magnetostrictive materials (Terfenol-D rods, Tb0.3 DY0.7 Fe2), is an interesting but difficult task. Not only the coupling between electromagnetic and mechanical phenomena is essential, it is also a full magnetomechanical nonlinear problem. Confronted with the need to come closer to the reality, nonlinear modelling is necessary. For this purpose a variational formulation is proposed to analyze, by using the Finite Element Method (FEM), the giant magnetostriction phenomena, particularly the Joule effect in the magnetostatic case. It is proved, using Euler's and Neumann's theorems, that the proposed model corresponds to the mathematical setting of the magnetomechanical coupled problem. It should be noted that the model is strongly based on static registrations of the magnetic and mechanical properties which are characteristically complex and nonlinear. A solution is then suggested to fit this type of experimental data through the thin sheets bending principle which is more efficient when used for finite element modelling.