Lijun Xue¹, Guansuo Dui^1,2, Bingfei Liu³

CMES-Computer Modeling in Engineering & Sciences, Vol.93, No.1, pp. 1-16, 2013, DOI:10.3970/cmes.2013.093.001

Abstract The Functionally Graded Shape Memory Alloy (FG-SMA) is a new kind of functional materials which possesses the excellent properties of both Shape Memory Alloy (SMA) and Functionally Graded Material (FGM). A macro constitutive model of FG-SMA is established by using the theory of the mechanics of composites and the existing SMA model. With this macro constitutive model, the mechanical behavior of a FG-SMA beam composed by elastic material A and SMA subjected to pure bending is investigated. The loading processes including elastic process and phase transformation process are discussed in detail and the analytical solutions are obtained. What is more,… More >

Bingfei Liu¹, Guansuo Dui^1,2, Yuping Zhu³

CMES-Computer Modeling in Engineering & Sciences, Vol.78, No.3&4, pp. 247-276, 2011, DOI:10.3970/cmes.2011.078.247

Abstract A constitutive model considering the effect hydrostatic stresses induced by porosity on the macroscopic behavior of porous Shape Memory Alloys (SMAs) is developed in this paper. First, a unit-cell model is adopted to establish the constitutive relations for the porous SMAs with SMA matrix and the porosity taken to be voids. Dilatational plasticity theory is then generalized for the SMA matrix. Based on an approximation of the velocity field and the upper bound theory, an explicit yield function for the porous SMA is derived from micromechanical considerations. Finally, an example for the uniaxial response under compression of a porous Ni-Ti… More >

M.K. Kang¹, E.H. Kim¹, M.S. Rim¹, I. Lee^1,2

CMES-Computer Modeling in Engineering & Sciences, Vol.64, No.3, pp. 227-250, 2010, DOI:10.3970/cmes.2010.064.227

Abstract An engineering model for predicting the behavior of shape memory alloy (SMA) wire is presented in this study. Piecewise linear relations between stress and strain at a given temperature are assumed and the mixture rule of Reuss bounds is applied to get the elastic modulus of the SMAs in the mixed phase. Critical stresses and strains of the start and finish of the phase transformation are calculated at a given temperature by means of a linear constitutive equation and a stress-temperature diagram. Transformation conditions based on the critical stresses are translated in terms of critical strains. Martensite volume fraction and… More >

F. Auricchio^{1,2,3,4,1,5,1}, M. Contisup>1,5,S. Morgantisup>1,, A. Reali^1,2,3

CMES-Computer Modeling in Engineering & Sciences, Vol.57, No.3, pp. 225-244, 2010, DOI:10.3970/cmes.2010.057.225

Abstract The use of shape memory alloys (SMA) in an increasing number of applications in many fields of engineering, and in particular in biomedical engineering, is leading to a growing interest toward an exhaustive modeling of their macroscopic behavior in order to construct reliable simulation tools for SMA-based devices. In this paper, we review the properties of a robust three-dimensional model able to reproduce both pseudo-elastic and shape-memory effect; then we calibrate the model parameters on experimental data and, finally, we exploit the model to perform the finite element analysis of pseudo-elastic Nitinol stent deployment in a simplified atherosclerotic artery model. More >

H.T. Li^1,2,3, Z.Y. Guo^1,2, J. Wen^1,2, H.G. Xiang^1,2, Y.X. Zhang^1,2

CMC-Computers, Materials & Continua, Vol.48, No.2, pp. 91-102, 2015, DOI:10.3970/cmc.2015.048.091

Abstract Ferromagnetic shape memory alloy particulate composites, which combine the advantages of large magnetic field induced deformation in ferromagnetic shape memory alloys (FSMAs) with high ductility in matrix, can be used for sensor and actuator applications. In this paper, a new constitutive model was proposed to predict the magneto-mechanical behaviors of FSMA particulate composites based on the description for FSMAs, incorporating Eshelby’s equivalent inclusion theory. The influencing factors, such as volume fraction of particles and elastic modulus, were analyzed. The magnetic field induced strain and other mechanical properties under different magnetic field intensity were also investigated. More >

Yuping Zhu^1,2, Tao Chen¹, Kai Yu¹

CMC-Computers, Materials & Continua, Vol.43, No.2, pp. 97-108, 2014, DOI:10.3970/cmc.2014.043.097

Abstract Based on an existing micromechanical constitutive model for Ni2MnGa ferromagnetic shape memory alloy single crystals, a three-dimensional quasi-static isothermal incremental constitutive model that is suitable for finite element analysis is derived by using Hamilton's variational principle. This equation sets up the coupling relation between the magnetic vector potential and the mechanical displacement. By using the incremental equation and ANSYS software, the mechanical behaviors of martensitic variant reorientation for Ni2MnGa single crystals are analyzed under magneto-mechanical coupling action. And the finite element results agree well with the experimental data. The methods used in the paper can well describe the mechanical behaviors… More >

F. Casciati¹, S. Casciati², L. Faravelli¹, A. Marzi¹

CMC-Computers, Materials & Continua, Vol.23, No.3, pp. 287-306, 2011, DOI:10.3970/cmc.2011.023.287

Abstract The potential offered by the main features of shape memory alloys (SMA) in Structural Engineering applications is object of attention since two decades. The main issues concern the predictability of the material behavior and the fatigue lifetime of macro structural elements (as different from wire segments). In this paper, the fatigue characteristics, at given temperatures, of multigrain samples of a specific Cu-based alloy are investigated. The results of laboratory tests on bar specimens are discussed. The target is to model the manner in which the effects of several loading-unloading cycles of different amplitude cumulate. More >

CMC-Computers, Materials & Continua, Vol.10, No.1, pp. 65-96, 2009, DOI:10.3970/cmc.2009.010.065

Abstract This work proposed an alternative formulation for the prediction of martensite start temperature (Ms) of Fe-Mn-Si shape memory alloys (SMAs) depending on the various compositions and heat treatment techniques by using Neural Network (NN) and genetic programming (GP) soft computing techniques. The training and testing patterns of the proposed NN and GP formulations are based on well established experimental results from the literature. The NN and GP based formulation results are compared with experimental results and found to be quite reliable with a very high correlation (R2=0.955 for GEP and 0.999 for NN). More >