(Dr. David McDowell, advisor)
"Simulation of Nickel-Titanium Superelastic Behavior"
Among Shape Memory Alloys (SMAs), Nickel-Titanium (NiTi) alloys have the greatest number of industrial applications. However, only limited finite element analyses that provide details of intergranular interaction have been conducted in the literature for these materials. The objectives of this work are to modify the transformation criterion to account for communal action of multiple compatible variants (i.e., use of Bain strain rather than evaluating transformation criterion for each of 24 variants independently), enhance predictive capability of models for NiTi SMA, to implement enhancements in an existing ABAQUS finite element User Material Subroutine, and to use this code to model experiments conducted by C. Dumont in an earlier thesis, along with additional experiments that exhibit stress state dependence.