Torsional Behavior of NiTi Wires and Tubes: Modeling and Experimentation

Torsional shape memory and superelastic NiTi elements provide low-profile, effective solutions for many biomedical applications such as orthopedic and orthotic devices. In this article, two different modeling approaches are used to model the torsional behavior of these alloys. For thin-walled tubes, a 1D model is adapted, while for thicker elements, a 3D model is chosen. Both of these models are implemented in the form of FE solutions. Experiments are conducted to find the modeling parameters, verify models, and compare the performance of these two modeling methods. These models are further used to for geometric and parametric studies of NiTi elements in torsion.