Modeling of Iron Based Shape Memory Alloys Behavior Within Finite Strain Formulation

This paper presents a finite-strain thermomechanical constitutive model for Iron based Shape Memory Alloys (Fe-SMAs). The model considers the multiphysical coupling between the phase transformation and the plasticity which distinguishes Fe-SMAs from classical SMAs (Ni-Ti and Copper based ones). Based on the multiplicative decomposition of deformation gradient into elastic, transformation and plastic components, the model is developed within a thermodynamically consistent framework. Model constitutive equations associated with the internal variables (volume fraction of martensite \(\chi \) and the accumulative plastic strain \(\gamma \)) are derived from the reduced form the constructed Lagrangian, which is the sum of the Helmholtz free energy function and the inner potential, and the Clausius-Duhem inequality. The model is used to simulate tensile experiments on Fe-SMAs specimens at different thermomechanical loadings. The good agreement of the model predictions demonstrates the capabilities of the proposed model to well the specific behavior of Fe-SMAs.