A Phenomenological Model for Superelastic $NiTi$ Wires Based on Plasticity With Focus on Strain-Rate Dependency Caused by Temperature

A simple one-dimensional model has been developed to illustrate methods to account for transformation bands in plasticity-based models. Austenite-martensite and martensite-austenite transformations are described by two transformation surfaces in analogy to yield surfaces in plasticity theory. The strain-rate dependence of the material behavior is caused solely by the latent heat of the transformations. Optical and thermographical experiments have been carried out to clarify the dependence of the transformation bands on the distribution of latent heat and therefore on the thermomechanical behavior.