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On the thermomechanics of shape memory wires. (English) Zbl 0951.74005

This paper proposes a continuum model of thermomechanical behavior of shape memory wires based on a theory of the authors [Int. J. Plast. 13, No. 1-2, 1-35 (1997; Zbl 0905.73002)] which takes into account multiple natural configurations of the body. The various storage and dissipation mechanisms are discussed in detail. The internal energy includes, besides the usual thermal energy, strain, latent and interfacial energies, and the entropy incorporates an entropy jump associated with phase transitions. Among the dissipation mechanisms, the authors give special attention to the role of mechanical dissipation in the entropy generation and in the description of hysteretic behavior. General constitutive equations consistent with previous mechanisms are derived and, for the sake of illustration, simple linear or quadratic forms are assumed for them. This allows to model the full shape memory response of wires. A procedure for determination of six constants intervening in the thermomechanical response is indicated and illustrated for CuZnAl and NiTi. The predictions of the theory are shown to be in remarkable agreement with experimental data. Some discrepancies with results of Y. Huo and Müller [Contin. Mech. Thermodyn. 5, 163-204 (1993; Zbl 0780.73006)] are pointed out and discussed.
Reviewer: D.Jou (Bellaterra)

MSC:

74A15 Thermodynamics in solid mechanics
74N30 Problems involving hysteresis in solids
74F05 Thermal effects in solid mechanics
80A22 Stefan problems, phase changes, etc.
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