Modeling and Simulation of Architectured Iron-Based SMA Materials

Wael Zaki,Cheikh Cissé,Tarak Ben Zineb

doi:10.1115/smasis2017-3759

Wael Zaki, Cheikh Cissé + Show 1 more

Open Access

https://doi.org/10.1115/smasis2017-3759

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Abstract

The paper presents results of finite element analysis of architectured iron-based shape memory alloy (SMA) samples consisting of bulk SMA and void combined to different proportions and according to different geometric patterns. The finite element simulation uses a constitutive model for iron-based SMAs that was recently developed by the authors in order to account for the behavior of the bulk material. The simulation of the architectured SMA is then carried out using a unit cell method to simplify calculations and reduce computation time. For each unit cell, periodic boundary conditions are assumed and enforced. The validity of this assumption is demonstrated by comparing the average behavior of one unit cell to that of a considerably larger sample comprising multiple such cells. The averaging procedure used is implemented numerically, by calculating volume averages of mechanical fields such as stress and strain over each finite element model considered as a combination of mesh elements.

Highlights

Shape memory alloys (SMAs) are known for their ability to experience severe deformation that can be recovered by heating or mechanical unloading
Fe-shape memory alloy (SMA) offer better machinability and manufacturability compared to NiTi [3; 4]
The results show the distribution of martensite within the volume of each cell upon compression of 2% in one of the axial directions starting from an unloaded austenitic state

Summary

INTRODUCTION

Shape memory alloys (SMAs) are known for their ability to experience severe deformation that can be recovered by heating or mechanical unloading This ability is a manifestation of reversible phase transformation between two solid phases: austenite and martensite, characterized by different degrees of crystallographic symmetry. Fe-SMAs offer better machinability and manufacturability compared to NiTi [3; 4] Despite their strong potential for engineering applications, constitutive models for FeSMAs, especially for the case of multiaxial loading, have only recently been developed [5; 6]. The loading functions Fmtr and Fatr, governing the evolution of dissipative variables ξ and p, where p is the cumulated plastic strain, are obtained by choosing the conjugate thermodynamic forces Atr and Apl to be sub-gradients of a dissipative potential D(ξ, p) given by.

Fmtr Fatr

ALGORITHMIC CONSIDERATIONS AND NUMERICAL

CONCLUSION