Abstract. This article reports on an ESF S3T EUROCORES sponsored networking activity called Roundrobin SMA modeling organized with the aim to compare capabilities of various thermomechanical models of shape memory alloys capable to simulate their functional responses for applications in smart engineering structures. Five sets of experimental data were measured in thermomechanical tests on thin NiTi filament in tension, torsion and combined tension/torsion. The data were provided to six teams developing advanced SMA models to perform appropriate simulations. Simulation results obtained by individual teams were compared with experimental results and presented on a dedicated Roundrobin SMA modeling website. The evaluation of the activity in terms of the assessment of the capability of individual models to deal with specific features of the experimentally measured SMA thermomechanical responses is provided in this article.

One important feature in the description of the shape memory alloys is the determination of the yield surfaces of phase transformation. They can be presented as surfaces in the phase transformation martensitic strain space. In this paper the transition from this stress to the classical stress space is performed. Two application cases concerning bi-axial loading (bi-tension and tension-torsion) are discussed in details.

At first, some comments are made concerning the capacity of prediction of the microstructure for shape memory alloys by the Crystallographical Theory of Martensite. Secondly, the basic foundations of the phenomenological modeling of shape memory alloys behavior at the macroscopic scale are given. A special attention is devoted to the yield surface of phase transformation initiation in the stress space and its convex dual: the set of effective transformation strains in the strain space.

Abstract. We present a model based on the phase transformation surface of SMA. This model is described per a thermodynamical point of view. We applied this modelling on an experimental part that has been realized by P. Sittner et al. on a nickel titane wire. We had several experimental sets with we could show the performances of our model, in particular when the taking into account of the asymmetry of the yield surface and the respect of the hysteresis width.

Abstract. We present a model based on the phase transformation surface of SMA. This model is described per a thermodynamical point of view. We applied this modelling on an experimental part that has been realized by P. Sittner et al. on a nickel titane wire. We had several experimental sets with we could show the performances of our model, in particular when the taking into account of the asymmetry of the yield surface and the respect of the hysteresis width.