Constitutive Laws for Pseudo-Elastic Materials

In this paper a new model of pseudo-elastic materials based on experimen tal observations of one-dimensional motions of SMA materials is introduced. The model incorporates phase fractions as an internal variable and allows for both reversible (elastic) and irreversible (plastic) modes inside the hysteresis loop. As such, the model accounts for a wider range of physical phenomena than the traditional plasticity theories. The consti tutive equations predict transitions between elastic and plastic modes through a de pendence on the time history of strain and phase fractions. These history effects are in cluded in a way that allows for easy computation.