Thermodynamic Modelling of Ferromagnetic Shape Memory Actuators

Abstract:

Article Preview

We present a thermodynamic Gibbs free energy model for the finite element simulation of the coupled thermo-magneto-mechanical behavior of ferromagnetic shape memory alloys (FSMAs). Starting from a free energy model for the conventional shape memory effect, additional terms are included to take into account the magnetic anisotropy and the geometry-dependent magnetostatic energy. Different functions are considered for the strain dependence of the anisotropy energy in order to describe the experimentally found strong dependence of the anisotropy energy on the ratio of short and long crystallographic axis c/a. The resulting energy landscape is used to calculate the transition probabilities between three martensite variants and the austenite state under applied stress and external magnetic field. The magnetic shape memory effect is simulated for different loading conditions and sample geometries. We demonstrate the influence of the c/a dependence of the anisotropy energy as well as the influence of twinning strain and elastic modulus on the transition between martensite variants. The model calculations are compared with experimental results on Ni-Mn-Ga single crystals.

Info:

Periodical:

Edited by:

V. A. Chernenko and J. M. Barandiaran

Pages:

175-180

Citation:

B. Krevet and M. Kohl, "Thermodynamic Modelling of Ferromagnetic Shape Memory Actuators", Materials Science Forum, Vol. 635, pp. 175-180, 2010

Online since:

December 2009

Export:

[1] K. Ullakko, J. K. Huang, C. Kantner, R. C. O´Handley, V. V. Kokorin, Appl. Phys. Lett 69 (1996. ), (1967).

[2] R. D. James, M. Wuttig, Philos. Mag. A77, (1998) 1273 - 1299.

[3] R. C. O´Handley, J. Appl. Phys. 83, (1998) 3263 - 3266.

[4] V. A. L'vov, E. V. Gomonaj, V. A. Chernenko, J. Phys: Condens. Matter 10 (1998) 4587 - 4595).

[5] S. Kim, S. Seelecke, Int. journal of SOLIDS and STRUCTURES, 44 (2007), 1196-1209.

[6] B. Krevet, M. Kohl, P. Morrison and S. Seelecke, Eur. Phys. J. Special Topics 158, 205-211 (2008).

[7] B. Krevet, M. Kohl and S. Seelecke, Proc. ICOMAT 08, Santa Fe, USA, (2008).

[8] A. Sozinov, A. A. Likhachev, and K. Ullakko, IEEE TRANSACTIONS ON MAGNETICS, VOL. 38, NO. 5, pp.2814-2816, Sept. (2002).

[9] J. Tellinen, I. Suorsa, A. Jääskeläinen, I. Aaltio and K. Ullakko, 8th international conference ACTUATOR 2002, Bremen, Germany, 10-12 June (2002).

[10] K. Rolfs, A. Mecklenburg, J. -M. Guldbakke, R.C. Wimpory, A. Raatz, J. Hesselbach and R. Schneider, J. Magn. Magn. Mater. (2008), doi: 10. 1016/j. jmmm. 2008. 10. 023.

Fetching data from Crossref.
This may take some time to load.