Finite strain modeling of coupled thermo-mechanical behavior of polycrystalline ni-ti shape memory alloys

Rezazadeh, Vahid
Shape memory alloys (SMAs) hold a significant importance in different areas such as aeronautics,adaptive structures,oil/gas down-hole, and high-temperature applications of automobile industry. Nowadays,researchers have already become well-aware of these applications and attempted to discover all the primary features of this specific smart material. Meanwhile, there is a growing effort to produce mathematical models in order to imitate the related behavior in a precise manner. Due to the crucial need to have a fine computational model, we established a constitutive theory based on the finite strain framework of continuum mechanics. The presented thermo-mechanically coupled model can perfectly reproduce all behavior of Ni-Ti SMAs including martensitic phase transformation, pseudoelasticity, and one-way shape memory effect. Our constitutive model is also able to investigate the strain-rate and temperature dependency of the loading conditions. This work aims at utilising finite strain plasticity set- ting with purely thermodynamically consistent constitutive equations. In this framework, a user material subroutine (UMAT) is written and implemented into ABAQUS/Implicit (2016) finite element program. Verification of the model is carried out by the calibrated experimental findings which exist in the literature. Numerical simulations of developed constitutive model successfully denote the ability of our phenomenological model in capturing different memory effects of Ni-Ti SMAs under stress-strain-temperature cycling.


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Citation Formats
V. Rezazadeh, “Finite strain modeling of coupled thermo-mechanical behavior of polycrystalline ni-ti shape memory alloys,” M.S. - Master of Science, Middle East Technical University, 2017.