A macromechanical total-deformation constitutive model of pseudoelasticity
previously developed by the authors is employed within a two-dimensional finite
element framework to numerically investigate the effect of strain rate and boundary
conditions on the overall mechanical response and nucleation/evolution of
transformation bands in NiTi strips during both forward and reverse transformations.
The simulation results are compared with the experimental observations
previously reported by other researchers, and it is shown that the present method
successfully captures the nucleation and propagation of localized deformation
bands during both loading and unloading. It is confirmed that the number of
propagating fronts plays a key role in the pseudoelastic response of material in
nonisothermal conditions. Special attention is paid to the morphology of the
transformation fronts and its evolution. The numerical analysis indicates that the
predicted morphology of the fronts is highly sensitive to imperfections and
misalignments in the boundary conditions, especially during the reverse
transformation.