Stress state effect on mechanical behaviour of shape memory alloys : Experimental characterisation and modelling

Abstract
As engineering components utilising the beneficial properties of shape memory alloys (SMA) become geometrically complex and as applications involve combinations of loading states, a full evaluation of the effects of stress state on stress-strain response of these materials becomes critical for the success of these applications. Such evaluation is required to establish reliable constitutive relationship to model the complex thermomechanical behaviour of SMAs. This paper is intended to present a non-exhaustive overview on studies and results dealing with experimental characterisation and modelling of the effects of stress state on mechanical behaviour of shape memory alloys. In that respect, our presentation is mainly focused on one hand on experimental results on superelastic and ferroelastic deformation of polycrystalline alloys and on the other hand on the modelling at the macroscopic level, yielding critical reorientation or transformation constitutive equations.