• Journal of Institute of Control, Robotics and Systems
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• v.10 no.11
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• pp.976-980
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• 2004

This study has introduced how to make conducting shape memory polyurethane(CSMPu) as a possible application to smart actuators. Different from conventional polyurethane, CSMPu can have a high conductivity and then electric power supplies enough energy to deform. To prepare conducting polyurethane, carbon nanotubes were incorporated into shape memory polyurethane. Basic experiments to reveal its characteristics have been conducted for a development of actuators. From the results conducted in the present study, optimized conditions for the process of actuating deformation were found. Thermo-electric characteristics such as the relation between temperature and specific resistance and trend curves of resistance variations according to elongations were measured. These data provided a strong possibility of CSMPu as a smart actuator.

• Electrical & Electronic Materials
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• v.9 no.6
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• pp.616-625
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• 1996

본 고에서는 최첨단 주사형 마이크로프로브현미경의 최근동향에 대해 기술하고자 한다. SNOAM의 관찰분야에의 응용이라는 관점에서 광학소자, 반도체재료, 유기박막등의 미소영역에의 광학특성의 관찰이외에 생물분야에서는 형광표식한 시료의 형상상과 형광상의 대비에서 세포나 생체고분자의 기능 해명에도 이용 가능하다고 생각된다. 또한 광가공기술에의 응용이나 기억소자 기술에의 응용도 고려되어져 금후의 응용분야에의 발전이 기대된다. 다가오는 21세기 정보화사회에서는 분자.원자를 제어하는 기술이 중심기술이 될 것으로 확신되고 있다. 그러나 현재 우리주변 기술로서 분자. 원자를 단위로 하는 평가, 분석 기술은 거의 찾을 수 없다. 따라서 주사형 마이크로 프로브 현미경은 Nano-technology로서 장래 정보화사회에 중요한 평가.분석기술의 하나로서 정착될것으로 생각된다.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.129-130
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• 2010

Lap splice of longitudinal reinforcing steels was located in the plastic hinge region of most bridge piers that had been designed and constructed before the adoption of the 1992 seismic design provision of Korea Highway Design Specification. This research aims at improving the seismic performance of reinforced concrete bridge piers with lap-spliced longitudinal steels, of which the plastic hinge region was wrapped by the shape memory alloy (SMA) wires. Quasi-static test was used to investigate the seismic behaviours of RC test specimens.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.11a
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• pp.145-148
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• 2005

In this study, adaptation of two-way shape memory effect of SMA wire to the actuator is examined . Therefore the SMA characteristics which are training, material properties, response time at different thermal cycling rates are tested. During training, permanent deformation is accumulated till a certain number of cycle and then saturated. The amow1t of two-way strain is unchangeable over all cycle and the slope of strain(or stress)-temperature curve is slower as the increase of applied stress. The rate effect is observed resulted from the thermal distribution which heating profile differs from cooling as thermal cycling time. Using the estimated SMA properties, an experimental test for the simple smart wing is performed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.04a
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• pp.465-469
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• 1997

In this paper, shape memory compsites are made by powder metallurgy. And then, an self-strengthening effect of the composites by shape memory effect above inverse transformation temperature A/sab f/ of TiNi alloy discussed. Moreover, TiNiCo/Al composite is made by using TiNiCo alloy as fiber. And it is discused aboutaffection of Co in the shape memory composite. The results of the intelligent properties of TiNi/Ai-radical shape memory composite, using SMA, by powder metallurgy are the tensile strength of TiNiCo wire is much higher than that of TiNi wire. and the strength of TiNiCo/Al composite is generally higher than that TiNi/Al composite.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.557-561
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• 2008

Shape memory alloys (SMA) have interesting features which are the superelastic effect (SE), shape memory effect (SME), two-way SME (TWSME), and so on. These are utilized in actuation factor. The thermo-mechanical constitutive equations of SMA proposed by Lagoudas et al. were employed in the present study for simulating SMA truss structures. The constitutive equation includes the necessary internal variables to account for the material transformations and is utilized in the non-linear finite element procedure of three dimensional truss structures that composed SMA bar (wholly or partially). In this study, we observed which element should be actuated to get a desired shape (actuation shape) from computational analysis. To reach this goal, we apply SMA constitutive equation to non-linear finite element formulation. And then, we simulate two-way shape memory effect as well as superelastic effect of various three dimensional truss using SMA.

• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1985-1987
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• 1996

Shape memory alloy springs have been fabricated and annealed at $400^{\circ}C$, $450^{\circ}C$ and $500^{\circ}C$ in atmosphere and in nitrogen gas. The optimal heat treatment condition in view of maximum generated force has been decided by the iso-thermal test with variation of annealing condition. Experimental results show that the heat treatment with high temperature in nitrogen gas is desirable for high generated force and can be used for the design of shape memory alloy springs.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.100-103
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• 2005

This work discusses the numerical analysis, the design and experimental test of the SMA (Shape Memory Alloy) actuator along with its capabilities and limitations. Convection heating and cooling using water actuate the SMA element of the actuator. The fuel such as propane, having a high energy density, is used as the energy source for the SMA actuator in order to increase power and energy density of the system, and thus in order to obviate the need for electrical power supplies such as batteries. The system is composed of a pump, valves, bellows, a heater (burner), control unit and a displacement amplification device. The actuation frequency is compared with the prediction obtained from numerical analysis. For the designed SMA actuator system, the results of numerical analysis were utilized in determining design parameters and operating conditions.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.04a
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• pp.10-13
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• 2003

The dynamic analysis of composite plate with embedded shape memory alloys (SMAs) is studied using the finite element method. Active frequency tuning of a composite plate under electrical heating of SMAs is analyzed. The actuation of SMAs is modeled by Brinson's one-dimensional constitutive equation. The influences of the boundary conditions, the ply orientations and the pre-strains of SMA wires on the thermo-dynamic response of composite plate are discussed. It is found that the effect of SMAs on the dynamic response of composite plate is significant.