Superelastic and shape memory effects for laminated SMA beams

A simple shape-memory-alloy (SMA) model to simulate the superelastic behavior as well as the shape memory effect is proposed. It considers only the transformations from austenite to single-variant martensite and from single-variant martensite to austenite, taking into account the influence of the temperature in the constitutive relationship. The proposed SMA constitutive model is employed in a novel layerwise beam theory to develop new SMA beam finite element models with suitable interpolation of the field variables involved. The finite element models developed herein account for the time evolution SMA constitutive equations. In particular, the developed finite elements treat the SMA material as reinforcement of elastic beams. Several applications are presented to assess the validity of the constitutive model and the proposed numerical procedure.