Thermomechanical model for NiTi-based shape memory alloys covering macroscopic localization of martensitic transformation
Abstract
The work presents a thermomechanical model for polycrystalline NiTi-based shape memory alloys developed within the framework of generalized standard solids, which is able to cover loading-mode dependent localization of the martensitic transformation. The key point is the introduction of a novel austenite-martensite interaction term responsible for the strain-softening of the material.
Mathematical properties of the model are analyzed, and a suitable regularization and a time-discrete approximation for numerical implementation to the finite-element method are proposed. Model performance is illustrated on two numerical simulations: the tension of a superelastic NiTi ribbon and bending of a superelastic NiTi tube. (C) 2020 Elsevier Ltd.
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