Modelling of SMA materials: Training and two way memory effects

The present work addresses a simple and effective one-dimensional model able to reproduce the superelastic behaviour as well as the shape memory effect. In particular, it considers the transformations from austenite to single variant martensite and from single variant martensite to austenite, taking into account the influence of the temperature. Moreover, the training and the two way memory effects are modelled considering the evolutions of the phase-transformation stress thresholds as well as of the residual “permanent” deformation. The time integration of the evolutive equations is performed adopting a backward Euler scheme and the finite time step is solved through a modified return-map algorithm. The proposed SMA constitutive law and numerical procedure are adopted to develop numerical applications. Finally, the ability of the model to reproduce experimental data is assessed.