Bingfei Liu^1,*, Yangjie Hao²

CMES-Computer Modeling in Engineering & Sciences, Vol.131, No.3, pp. 1601-1613, 2022, DOI:10.32604/cmes.2022.019226

Abstract By adding copper to increase the performance, the Ni-Ti-Cu Shape Memory Alloy (SMA), has been widely used in the field of engineering in recent years. A thermodynamic constitutive model for Ni-Ti-Cu SMA considering different copper contents is established in this work. Numerical results for two different copper contents, as examples, are compared with the experimental results to verify the accuracy of the theoretical work. Based on the verified constitutive model, the effects of different copper content on the mechanical properties of Ni-Ti-Cu SMA and the tensile and compressive asymmetric properties of Ni-Ti-Cu SMA are finally discussed, respectively. More >

F. Auricchio¹, L. Petrini², R. Pietrabissa³, E. Sacco⁴

CMES-Computer Modeling in Engineering & Sciences, Vol.4, No.3&4, pp. 365-380, 2003, DOI:10.3970/cmes.2003.004.365

Abstract Since 80’s many devices were developed to exploit the unique blend of mechanical and biocompatibility properties of shape memory alloys in orthodontic applications. It results in a high clinical effectiveness, but also in a spreading of technical knowledge on the properties of the single appliances. The goal of the present contribution is to contrast this sense of bewilderness and to prepare the basis for a simulationtool able to support the orthodontist choice. In particular a finite-element beam with a one-dimensional constitutive law, able to describe the SMA super elasticity and shape memory effect, is presented: it is shown how computer… More >

Liu Bingfei, Dui Guansuo, Zhu Yuping

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.3, pp. 73-74, 2011, DOI:10.3970/icces.2011.017.073

Abstract Several constitutive models with different yield functions for porous shape memory alloy (SMA) are compared with the experimental date. Different approaches such as upper bound theory and lower bound theory have been adopted and a new correction formula of the yield function is proposed in this work to study the behavior of porous SMAs. Numerical results are compared with the experimental date by Zhao et al (2005). It shows that the researches using upper bound and lower bound are nearly the same and the new correction formula is much closer to the experimental data than others. More >

Hsin-Yu Chen, Nien-Ti Tsou^*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.3, pp. 55-55, 2019, DOI:10.32604/icces.2019.05403

Abstract Shape memory alloys has been widely applied on actuators and medical devices. The transformation temperature and microstructural evolution play the crucial factors and dominate the behavior of shape memory alloys. In order to understand the influence of the composition of the Ni-Ti on the two factors, molecular dynamics (MD) is adopted to simulate the temperature-induced phase transformation in the current study. In addition, the results are post-processed by the martensite variant identification method. The method allows to reveal the detailed microstructural evolution and the volume fraction of each variant/phase in each case of the composition of Ni-Ti. Many features that… More >

K. Williams¹, T. Cagin^1,2

The International Conference on Computational & Experimental Engineering and Sciences, Vol.15, No.4, pp. 153-160, 2010, DOI:10.3970/icces.2010.015.153

Abstract Designing magnetic shape memory materials with practicable engineering applications requires a thorough understanding of their electronic, magnetic, and mechanical properties. Experimental and computational studies on such materials provide differing perspectives on the same problems, with theoretical approaches offering fundamental insight into complex experimental phenomena. Many recent computational approaches have focused on first-principles calculations, all of which have been successful in reproducing ground-state structures and properties such as lattice parameters, magnetic moments, electronic density of states, and phonon dispersion curves. With all of these successes, however, such methods fail to include the effects of finite temperatures, effects which are critical in… More >

Bashir S. Shariat^*, Sam Bakhtiari, Hong Yang, Yinong Liu

The International Conference on Computational & Experimental Engineering and Sciences, Vol.21, No.1, pp. 21-21, 2019, DOI:10.32604/icces.2019.05559

Abstract Shape memory alloys (SMAs) are a unique collection of materials which can return to their initial configuration after being largely deformed. Near-equiatomic NiTi is the most widely used SMA due to its excellent shape memory properties and fabricability. One exceptional property of this alloy is superelasticity, which refers to the ability of the alloy to accommodate relatively large deformation typically up to 8% of tensile strain and return to the original undeformed shape upon unloading. As a result of this outstanding feature, superelastic NiTi have been increasingly used in different areas of engineering, such as in biomedical engineering and in… More >

B. Chen^1,2, X. Peng^1,2,3, X. Chen^1,2, J. Wang⁴, H. Wang⁴, N. Hu^1,5,6

CMC-Computers, Materials & Continua, Vol.30, No.2, pp. 145-176, 2012, DOI:10.3970/cmc.2012.030.145

Abstract A three-dimensional phenomenological model for coupled transformation and plastic behavior of shape memory alloys (SMAs) is presented. The strain is separated into elastic, thermal, transformation and plastic strain parts, and two yield functions are adopted to describe respectively the transformation and plastic deformation. An integral algorithm is suggested, including the update of the stress and the tangent stiffness. Numerical examples and the comparison with experimental results show that the proposed approach can well describe the behavior of the SMAs subjected to complicated thermal-mechanical loading, demonstrating the validity of the model in the description of the constitutive behavior of SMAs, including… More >

Hsin-Yu Chen¹, Nien-Ti Tsou^1,*

CMES-Computer Modeling in Engineering & Sciences, Vol.120, No.2, pp. 319-332, 2019, DOI:10.32604/cmes.2019.06447

Abstract Shape memory alloys has been widely applied on actuators and medical devices. The transformation temperature and microstructural evolution play two crucial factors and dominate the behavior of shape memory alloys. In order to understand the influence of the composition of the Ni-Ti alloys on the two factors, molecular dynamics was adopted to simulate the temperature-induced phase transformation. The results were post-processed by the martensite variant identification method. The method allows to reveal the detailed microstructural evolution of variants/phases in each case of the composition of Ni-Ti. Many features were found and having good agreement with those reported in the literature,… More >

Yuping Zhu^1,2, Tao Shi¹, Yuanbing Wang¹

CMES-Computer Modeling in Engineering & Sciences, Vol.95, No.6, pp. 501-517, 2013, DOI:10.3970/cmes.2013.095.501

Abstract Single crystal ferromagnetic shape memory alloy is a kind of new intelligent materials, it shows obvious anisotropy. Micromechanics theory has been used to analyze the whole mechanical behaviors of this material. However, Eshelby’s tensor of this material which plays an important role has still not solved efficiently. Based on the existing micromechanics constitutive model, this paper analyzes the numerical calculation formula of Eshelby’s tensor of anisotropic ferromagnetic shape memory alloy. Adopting the way of Gauss integral, the optimal Gaussian integral points for different inclusion shapes and the corresponding numerical solution of Eshelby’s tensor are obtained.Furthermore, the influence of inclusion shapes… More >

Bingfei Liu¹, Guansuo Dui^2,3, Lijun Xue², Benming Xie¹

CMES-Computer Modeling in Engineering & Sciences, Vol.94, No.3, pp. 239-260, 2013, DOI:10.32604/cmes.2013.094.239

Abstract Analytical solutions are derived for the macroscopic behaviors of a Shape Memory Alloy (SMA) thick-walled cylinder subjected to internal pressure and radial temperature gradient. The Tresca transformation criterion and linear hardening are used. Equations are given for the radial and circumferential stresses, transformation strains and martensite volume fractions at both the elastic step and the transformation step. Numerical results are presented and in good agreement with the finite element simulations. More >