• Proceedings of the Korean Society For Composite Materials Conference
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• 2003.10a
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• pp.146-149
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• 2003

Two-way shape memory effect(TWSME) under residual stresses are considered in the present study. The structure using two-way shape memory alloy(SMA) concept returns to its initial shape by increasing or decreasing temperature under the initially given residual stress. In the present study, we use a thermo-mechanical constitutive equation of SMA and laminated composite plates are considered as simple morphing structural components which are based on first order shear deformable laminated composite plate with large deflection. Numerical results of fully coupled SMA-composite structures are presented

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.6
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• pp.67-76
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• 2020

This paper reports an experimental study to evaluate the flexural behavior of concrete beams reinforced using Fe based shape memory alloy (Fe-SMA) bars. For the experiment, a concrete beam of 200mm×300mm×2,200mm was produced, and a 4% pre-strained Fe-SMA bar was used as a tensile reinforcement. As experimental variables, type of tensile reinforcement (SD400, Fe-SMA), reinforcement ratio (0.2, 0.39, 0.59, 0.78), activation of Fe-SMA (activation, non-activation), and joint method of Fe-SMA bar (Continuous, welding, coupler) were considered. The electric resistance heating method was used to activate the Fe-SMA bar, and a current of 5A/㎟ was supplied until the specimen reached 160℃. After the upward displacement of the specimen due to the camber effect was stabilized, a three-point flexural loading experiment was performed using an actuator of 2,000 kN capacity. As a result of the experiment, it was found that the upward displacement occurred due to the camber effect as the Fe-SMA bar was activated. The specimen that activated the Fe-SMA bar had an initial crack at a higher load than the specimen that did not activate it. However, as with general prestressed concrete, the effect of the prestress by Fe-SMA activation on the ultimate state of the beam was insignificant.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.329-330
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• 2006

The research and development of an actuator are accelerating in the robotics industry. The electricity polymer and SMA actuator are designed simply and are produced a lot of forces per unit volume. Their motions are similar to human's motion, But the repeatability of the electricity polymer actuator is lower. The reaction velocity of the SMA actuator is slow and the travel is short. In this paper, the dynamic characteristic of the segmented SMA is studied. The SMA wire is divided by using the Thermo-electric module(TEM) to control each of segments independently. The MOSFET circuit is used to supply constant currents fer the Thermo-electric module(TEM). The hysteresis and displacement of the SMA wire according to load are measured.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.67-71
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• 2003

A hot press method was used to create the optimal fabrication condition for a Shape Memory Alloy(SMA) composite. The bonding strength between the matrix and the reinforcement within the SMA composite by the hot press method was more increased by cold rolling. In this study, the objective was to develop an on-line monitoring system in order to prevent the crack initiation and propagation by shape memory effect in SMA composite. Shape memory effect was used to prevent the SMA composite from crack propagation. For this system an optimal AE parameter should be determined according to the degree of damage and crack initiation. When the SMA composite was heated by the plate heater attached at the composite, the propagating cracks could be controlled by the compressive force of SMA.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.3
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• pp.301-307
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• 2010

Actuation using a shape memory alloy (SMA) is considered to be an important technology that will play a leading role in market for next-generation medical devices because an SMA actuator can accurately imitate skillful and delicate hand movements. However, SMA actuators have not been successfully used because of problems in control design caused by the nonlinear hysteresis effect of SMA, which leads to inaccuracies in control systems. In order to overcome the effect, the authors invented a SMA actuator, which could actively and rapidly cool down and heat up, by combining a SMA catheter and a TE module using the Peltier effect. In order to evaluate the TE characteristics of our TE module system, the changes in the temperature with 1) incremental increases in a continuous electric current and 2) the appearance of a discontinuous constant or reverse current are discussed in this paper.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.335-336
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.317-318
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• 2010

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.113-114
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.193-194
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• 2010

• Composites Research
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• v.20 no.3
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• pp.37-42
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• 2007

Tensile residual stress is occurred by difference of coefficients of thermal expansion between fiber and matrix is one of the serious problems in metal matrix composite(MMC). TiNi alloy fiber was used to solve the problem of the tensile residual stress as the reinforced material. TiNi alloy fiber improves the tensile strength of composite with occurring of compressive residual stress in the matrix by its shape memory effect. A hot press method was used to create the optimal fabrication condition for a Shape Memory Alloy(SMA) composite. The bonding effect of the matrix and the reinforcement within the SMA composite by the hot press method was strengthened by cold rolling. In addition, acoustic emission technique was used to quantify the microscopic damage behavior of cold rolled TiNi/A16061 shape memory alloy composite at low temperature. The damage degree for the specimen that underwent thermal shock cycles was also discussed.