Modeling the Torsional Behavior of Superelastic Wires

Torsional behavior of shape memory alloys can be employed in different biomedical applications. The goal of this paper is to investigate the behavior of these alloys under torsional loading conditions. To this end a torsional model is developed in MATLAB, in which a uniaxial model is extended to predict the torque-angle behavior of superelastic wires/rods. Tensile and torsional testing are performed on NiTi wires to determine martial properties and to verify this model. The material properties are determined based on ASTM standards. The effect of different parameters such as lengths and radii on the torque-angle behavior are investigated with the model. Moreover, the effect of temperature on the torsional behavior of SMA wires are presented.