Numéro |
J. Phys. IV France
Volume 112, October 2003
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Page(s) | 977 - 980 | |
DOI | https://doi.org/10.1051/jp4:20031044 |
J. Phys. IV France 112 (2003) 977
DOI: 10.1051/jp4:20031044
Internal variable model for magneto-mechanical behaviour of ferromagnetic shape memory alloys Ni-Mn-Ga
L. Hirsinger and C. LexcellentLaboratoire de Mécanique Appliquée RC, UMR 6604 du CNRS, Institut des Microtechniques de Franche-Comté, FR 0067, 24 chemin de l'Épitaphe, 25000 Besançon, France
Abstract
In this paper, a predictive model of field-induced strain in Ferromagnetic Shape Memory Alloy (FSMA) is proposed. This phenomenological
scalar magneto-mechanical model is built in the frame of thermodynamic of irreversible process. The strain mechanism corresponds
to the reorientation process of twinned martensite platelets at constant temperature. In this model, physical microstructure
parameters are chosen as variables: volume fraction z of one martensite variant and ratio
of magnetic domain width. Pure mechanical behaviour of FSMA is supposed to be decomposed in reversible (or anhysteretic)
part and irreversible one. From dissipation, a yield function written in terms of energy, has been introduced to determine
when reorientation of twinned martensite platelets (via internal variable z) could occur. Pure magnetic behaviour is supposed
to be non-liner reversible. The coupling between magnetism and mechanics is introduced in the expression of magnetisation
via microstructure parameters z and a. The good prediction capability of the proposed model is shown by an identification
made on experiments performed by O'Handley & Murray: simulations of strain induced by pure mechanical loading or by applied
magnetic field under constant compressive stress, are presented and compared with these experiments. These first results are
very promising.
© EDP Sciences 2003