Constitutive modeling and finite element approximation of B2-R-B19 ' phase transformations in Nitinol polycrystals

A path-dependent constitutive model is proposed for the stress-induced phase transformation of Nitinol single crystals between austenite, rhombohedral and martensite phases. A multi-directional active set strategy is employed to resolve the path and state of the transformation. The resulting algorithm is implemented using a multi-scale finite element-based method which extends the applicability of the model to textured Nitinol polycrystals. Representative numerical simulations are included and show good agreement with experimental results. (C) 2009 Elsevier B.V. All rights reserved.