Magnetization- and strain-dependent free energy model for FEM simulation of magnetic shape memory alloys
Forschungszentrum Karlsruhe, IMT, Postfach 3640, 76021 Karlsruhe, Germany
2 Department of Mechanical & Aerospace Engineering, North Carolina State University, Raleigh, NC, 27695-7910, USA
A free-energy function is constructed, which couples strain and magnetic moments in ferromagnetic shape memory alloys. The associated Gibbs function is used to calculate time-dependent transition probabilities between martensite variants in a magnetic field under applied stress. By keeping track of the variant fractions, the evolution of strain and magnetization is determined. The simulation model is built in a finite element program for structural analysis, in order to simulate magnetic field-dependent strain and magnetization characteristics of a test actuator. The influence of material parameters and sample geometry is discussed.
© EDP Sciences, Springer-Verlag, 2008