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 - 19 April 2022

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 More >

MANIKANDAN.N^1,*, RAJESH.P.K¹

Journal of Polymer Materials, Vol.38, No.3-4, pp. 327-336, 2021, DOI:10.32381/JPM.2021.38.3-4.12

Abstract In this research, a new method to fabricate multi-material, multi-shape changing polymer composites is proposed. The method aims to reduce the number of thermomechanical programming steps involved in achieving shape change in a shape memory polymer (SMP) composite structure by including the programming steps directly into the printing process. After a single step of mechanical deformation and thermal loading, the SMP fibers can be activated sequentially to control the shape change. Composite strip samples were fabricated using a Stratasys Objet 260 multimaterial printer. Two polymer inks VeroPureWhite and Agilus30 were used as primary materials. The… More >

Yangling Li¹, Zhengrong Li¹, Hui Yu¹, Gang Huang¹, Xiaopeng Pei², Kun Xu^2,*, Pixin Wang², Ying Tan^3,*

Journal of Renewable Materials, Vol.9, No.8, pp. 1365-1376, 2021, DOI:10.32604/jrm.2021.014909 - 08 April 2021

Abstract In this work, the –catechol and –thiol modified starch was prepared by the esterification and amino condensation reaction, then a fully starch based hydrogel was prepared via the thiol-catechol Michael addition reaction. The starch hydrogel gained shape memory behaviors by coordinate with Fe³⁺ ions at alkaline condition. ¹ H-NMR had been used to character the structure of the starch derivatives and its character peaks. The hydrogel’s modulus had also been measured before and after coordinating with Fe³⁺ ions in linear area and the result showed that both the hydrogel’s storage modulus and loss modulus kept constant in More >

KRISHAN KUMAR PATEL, RAJESH PUROHIT

Journal of Polymer Materials, Vol.36, No.1, pp. 23-37, 2019, DOI:10.32381/JPM.2019.36.01.3

Abstract Microwave (MV)-induced thermo-responsive shape memory thermoplastic polyurethane (SMTPU)/ MWCNT composites were prepared in micro-compounder. Composites containing different amount of multiwall Carbon nanotube (MWCNT) varying from 0 to 1.5 phr in SMTPU matrix were prepared. Maximum stretching strength, recovery force and tensile strength for 1.5 CNTPU (1.5 phr MWCNT in SMTPU matrix) was increased by 120%, 100% and 24% respectively as compared to SMTPU. MV-induced shape memory is a novel approach for fast, clean and remote heating during operation. MWCNT is strong absorber of microwave irradiation so that SMTPU/ MWCNTs nanocomposites successfully triggered by microwave. 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 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… 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 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 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, More >