• Title, Summary, Keyword: shape memory

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A Theoretical Comparison of Two Possible Shape Memory Processes in Shape Memory Alloy Reinforced Metal Matrix Composite

  • Lee Jae Kon;Kim Gi Dae
    • Journal of Mechanical Science and Technology
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    • v.19 no.7
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    • pp.1460-1468
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    • 2005
  • Two possible shape memory processes, austenite to detwinned martensite transformation and twinned martensite to detwinned martensite transformation of a shape memory alloy have been modeled and examined. Eshelby's equivalent inclusion method with Mori-Tanaka's mean field theory is used for modeling of the shape memory processes of TiNi shape memory alloy reinforced aluminum matrix composite. The shape memory amount of shape memory alloy, plastic strain and residual stress in the matrix are computed and compared for the two processes. It is shown that the shape memory amount shows differences in a small prestrain region, but the plastic strain and the residual stress in the matrix show differences in the whole prestrain region. The shape memory process with initially martensitic state of the shape memory alloy would be favorable to the increase in the yield stress of the composite owing to the large compressive residual stress and plastic strain in the matrix.

Shape Recovery and Dynamic Compression Properties of Shape Memory Foams for the Insole of Shoes (신발 인솔용 형상기억 발포체의 동적압축 및 형상회복 특성)

  • Lim, Sung-Wook;Park, Eun-Young;Park, Cha-Cheol
    • Textile Science and Engineering
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    • v.48 no.6
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    • pp.380-385
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    • 2011
  • To develop memory foams for the insole of shoes. In order to examine the effect that the types of foam plays on compression set, shape memory characteristics commercial EVA foams and shape memory foams were produced. Cross-linking agents are used in the production of the shape memory foam. The effects that the types of crosslinking agents have on the shape memory characteristics. Shape memory foams appeared to have excellent shape recovery property. They experienced less plastic deformation to compression than the regular foams. Therefore, shape memory foam proved to be more suited for the insole of shoes than the commercial EVA foam. As the percentage of sulfur increased in the cross-linking agent that is used in the production of the shape memory foam, the shape memory characteristic also improved significantly.

A Study on the Improvement of Interfacial Bonding Shear Strength of Ti50-Ni50 Shape Memory Alloy Composite (Ti_{50}-Ni_{50} 형상기억합금 복합체의 계면 접학 전단강도 향상에 관한 연구)

  • Lee, Hyo-Jae;Hwang, Jae-Seok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.24 no.10
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    • pp.2461-2468
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    • 2000
  • In this paper, single fiber pull-out test is used to measure the interfacial bonding shear strength of $Ti_{50}-Ni_{50}$ shape memory alloy composite with temperature. Fiber and matrix of $Ti_{50}-Ni_{50}$ shape memory alloy composite are respectively $Ti_{50}-Ni_{50}$ shape memory alloy and epoxy resin. To strengthen the interfacial bonding shear stress, various surface treatments are used. They are the hand-sanded surface treatment, the acid etched surface treatment and the silane coupled surface treatment etc.. The interfacial bonding shear strength of surface treated shape memory alloy fiber is greater than that of surface untreated shape memory alloy fiber by from 10% to 16%. It is assured that the hand-sanded surface treatment and the acid etched surface treatment are the best way to strengthen the interfacial bonding shear strength of $Ti_{50}-Ni_{50}$ shape memory composite. The best treatment condition of surface is 10% HNO$_3$ solution in the etching method to strengthen the interfacial bonding shear strength of $Ti_{50}-Ni_{50}$ shape memory alloy composite.

Manufacture and Properties of Shape Memory Polyurethane Fibers (형상기억 폴리우레탄 섬유의 제조 및 물성평가)

  • Hong, Seok-In;Youk, Ji-Ho;Yu, Woong-Ryeol
    • Textile Science and Engineering
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    • v.47 no.2
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    • pp.85-91
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    • 2010
  • A shape memory polyurethane (SMPU) with a transition temperature of $28^{\circ}C$ was synthesized to investigate its fiber formation characteristics. Based on the thermal analysis a melt spinning process was designed, from which mono- and multi-filaments of SMPU fibers were manufactured. The shape memory performance of both SMPU film and fibers was evaluated using a thermo-mechanical cyclic test. The results revealed that SMPU fibers show similar shape memory behavior to that of SMPU film. The effect of post treatments such as annealing, drawing and heat-set on the shape memory performance of SMPU fibers was investigated and their effects on the micro-structural change of SMPU fibers were analyzed using a molecular configuration model. It was demonstrated that the properties of SMPU fibers can be tailored using these post treatments, thereby shape memory woven fabrics can be developed using SMPU fibers.

Development and Analysis of Physical Property of PP Shape Memory Fabrics for Emotional Garment (감성의류용 형상기억 PP직물 소재 개발과 물성분석)

  • Kim, Hyun-Ah;Kim, Seung-Jin
    • Science of Emotion and Sensibility
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    • v.14 no.1
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    • pp.117-126
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    • 2011
  • This study investigates the physical properties and manufacturing method of shape memory fabric for emotional garment made by polypropylene. For this purpose, polypropylene(PP) POY and SDY were texturized using low temperature and constant length heat treatment texturing technologies, respectively. The shape memory fabrics made using these texturized PP yarns were woven with two kinds of PET and PTT shape memory yarns on the air-jet loom and the various physical properties of four kinds of shape memory fabrics were measured and discussed. The tenacity and breaking strain of PP texturized yarns treated by low temperature and constant length heat treatment showed high weaving efficiency and the wet thermal shrinkage of PP textured yarns was shown less than 1.5%, dry thermal shrinkage was ranged between 3% and 5%, which means thermal stability compared to the PTT textured yarn with high thermal shrinkage, 5~8%. The shape memory characteristics of PP shape memory fabrics measured by Toray method showed five grade as same value as PTT shape memory fabric. The heat keeping property of the PP shape memory fabric showed 56% higher value than that of PTT shape memory fabric. The water repellency of PP shape memory fabric measured by spray method showed five grade as same value as PTT shape memory fabric treated with water repellent agent. Especially, shape memory properties of PP shape memory fabric measured by 3-D image and camera measurement methods showed similar characteristics to the PTT shape memory fabric.

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Development and Application of Conducting Shape Memory Polyurethane Actuators (전도성 형상 기억 폴리우레탄 작동기의 개발 및 응용)

  • Paik, Il-Hyun;Jung, Yong-Chae;Cho, Jae-Hwan;Goo, Nam-Seo
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.226-230
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    • 2005
  • This paper presents the actuation performance of a conducting shape memory polyurethane (CSMPU) actuator. We introduced a concept of shape memory polyurethane activated by electric power while conventional shape memory polyurethanes are activated by external heat source. A conducting shape memory polyurethane actuator was manufactured by adding cabon nano-tube to conventional shape memory polyurethane. The main problem of the previous CSMPU was bad dispersion of carbon nano-tubes in polyurethane. In this paper, we have tried to find manufacturing method to solve the dispersion problem. With a lot of elaborative works, we have developed conducting shape memory polyurethane actuator with good electrical performance. The actuation performance of the developed conducting shape memory polyurethane actuator was measured and assessed.

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Development and Application of Porous Superelastic TiNi Materials for Medical Implants

  • Gjunter, V.E.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • pp.7-7
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    • 1998
  • Research activities of Russian Medical Engineering Center and Institute of Medical Materials of Shape Memory Alloys and Implants are presented as follows: ${\bullet}$ The direction of elaboration of porous shape memory alloys for medicine. ${\bullet}$ Medical and technical requirements and physical and mechanical criteria of porous shape memory implants elaboration. ${\bullet}$ Basic laws of heat-, stress- and strain-induced changes of mechanical properties, shape memory effect and superelasticity in porous TiNi-based alloys. ${\bullet}$ Methods of regulation of shape memory effect parameters in porous alloys and methods for controlling the regulation-induced changes of physical and mechanical properties. ${\bullet}$ Original technologies of elaboration of porous alloys In various fields of medicine. ${\bullet}$ Arrangement of serial production of shape memory porous implants and examples of their medical use.

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Thermomechanical Behaviors of Shape Memory Alloy Using Finite Element Analysis (유한요소해석을 이용한 형상기억합금의 열적/기계적 거동 연구)

  • ;Scott R. White
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • pp.833-836
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    • 2001
  • The thermomechanical behaviors of the shape memory alloy were conducted through the finite element analysis of ABAQUS with UMAT user subroutine. The unified thermomechanical constitutive equation suggested by Lagoudas was adapted into the UMAT user subroutine to investigate the characteristics of the shape memory alloy. The three cases were solved to investigate the thermomechanical characteristics of the shape memory alloy. The material properties for the analysis were obtained by DSC and DMA techniques. According to the results, the thermomechanical characteristics, such as a shape memory effect and a pseudoelastic effect, could be obtained through the finite element analysis and the analysis results were revealed to agree well with the experimental results. Therefore, the finite element analysis using UMAT user subroutine is one of prominent analysis techniques to investigate the thermomechnical behaviors of the shape memory alloy quantitatively.

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Synthesis and Characteristics of 2 Step-curable Shape Memory Polyurethane (2단계 경화형 형상기억 폴리우레탄의 합성 및 분석)

  • Noh, Geon Ho;Lee, Seungjae;Bae, Seong-Guk;Jang, Seong-Ho;Lee, Won-Ki
    • Journal of Environmental Science International
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    • v.27 no.11
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    • pp.1023-1028
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    • 2018
  • Shape memory materials are widely used in high-tech industries. Although shape memory polymers have been developed, they have a disadvantage, only unidirectional resilience. Shape memory polymers with bi-directional recovery resilience have been actively studied. In this study, a bidirectional shape memory polyurethane was synthesized using poly(${\varepsilon}$-caprolactone) diol, methylene dicyclohexyl diisocyanate, and hydroxyethyl acrylate. The first physical curing occurred between hard segments and hydrogen bondings when the solution was dried. The second curing in acrylate groups was performed by UV exposure. A degree of curing was analyzed by infrared spectroscopy. The shape memory properties of 2 step-cured polyurethanes were investigated as a function of UV curing time.

Workpiece-Chucking Device Using Two-Way Shape Memory Alloys: Feasibility Test (양방향성 형상기억합금을 이용한 공작물 척킹장치: 유용성 검증)

  • Shin, Woo-Cheol;Ro, Seung-Kook;Park, Jong-Kweon
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.18 no.5
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    • pp.462-468
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    • 2009
  • In this study, a workpiece-chucking device that generates a chucking force from a shape memory alloy is introduced. This paper first presents train procedure to transform a commercial one-way shape memory alloy into a two-way shape memory alloy, which makes unclamping mechanism of the chucking device simpler than that using the one-way shape memory alloy Second, it describes a conceptual design of the workpiece-chucking device using the two-way type shape memory alloy. Third, it presents a prototype and its chucking characteristics, such as time-response of clamping/unclamping operations and a relationship between temperatures and chucking forces. Finally, it describes a mill-machining test conducted with the prototype. The results confirm that the proposed workpiece-chucking device is feasible for micro machine-tools.

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