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 >

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 composite strip consists of fiber… More >

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 >

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

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 linear area from… 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 >

L.Y. Wang, W. B. Song Z.D. Wang

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.1, pp. 13-14, 2011, DOI:10.3970/icces.2011.017.013

Abstract Shape memory epoxies and their composites have great potential applications in future deployable space structures industry. In this study six types of shape memory epoxies with different shape transition temperatures were synthesized by varying the curing agents and their contents. Thermal frozen/recovery test, DSC and DMA were performed to investigate their shape memory behaviors and thermomechanical properties. Further discussions about the testing results were presented with consideration of the microstructure. More >

Zhengfa Li, Weibin Song, Zhengdao Wang

The International Conference on Computational & Experimental Engineering and Sciences, Vol.17, No.1, pp. 11-12, 2011, DOI:10.3970/icces.2011.017.011

Abstract By using the high froze/recovery strains of shape memory polymers to meet the requirements of deployable space structures, the folding behavior of shape memory tape spring structures consisting of shape memory polymer and metal spring was analyzed. Firstly, numerical simulations were performed on the buckling modes and affecting factors under the equal- and opposite-sense bends. The results show that the folding deformations of such structure in the two cases are completely different. The equal-sense bending leads to the structure buckled abruptly, but gradual torsion buckling is received in the case of opposite-sense bending. The critical bending moments have big difference… 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 >