Modelagem constitutiva de ligas magnéticas com memória de forma

Abstract

Magnetic shape memory alloys (MSMAs) have the ability to deform under thermo, mechanical or magnetic fields actuation, offering the option of contactless control for high excitation frequencies. These characteristics make MSMAs a potential candidate for a new generation of sensors and actuators that produce large stroke/force and high opeeration frequency. This work concerns with a novel constitutive model based on internal variables that describe the phenomenological behavior of MSMAs. The model formulation is developed within the framework of continuum mechanics and thermodynamics, defining a mixture for the free energy potential based on four macroscopic phases. Zeeman effect is considered to incorporate the magnetic behavior. A numerical procedure is proposed to deal with the nonlinearities of the model. Model predictions are presented for different loadings, thermomechanical and magnetic phase transformations and reorientation. Numerical simulations are carried out showing the model capabilities and comparisons with experimental data available in the literature attest its ability to capture the general thermo-magneto-mechanical behavior of MSMAs.