• Journal of the Korean Society of Clothing and Textiles
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• v.36 no.4
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• pp.382-390
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• 2012

This study shows the optimum attachment of Two-Way Shape Memory Alloy (TWSMA) springs onto thermal liner and its sewing method for the mass production of fire fighter's intelligent turnout gear. SMA springs were attached to the fabric by four different methods and stitched by two different shapes (square and wave). The durability of the attached springs was tested by laundering up to 50 cycles. Examined were whether the springs would remain attached to the fabric after repeated laundering, the shape memory effect and reaction of the springs, and the anti-corrosiveness of the springs. A Human-Clothing-Environment simulator evaluated thermal insulation according to attachment methods, air layer volume, and stitch types. The findings showed that silicon attached springs remained intact after repeated laundering; in addition, repeated laundering did not influence the responsiveness and anti-corrosiveness of SMAs. Air volume had positive relations with the insulation. Attachment methods or stitch methods had limited impact on the thermal insulation. As a result, a wave type stitch with silicone attachment was suggested as the optimum method to attach the SMA springs onto the intelligent turnout gear for fire fighters.

• Smart Structures and Systems
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• v.14 no.5
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• pp.765-784
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• 2014

In comparison with conventional shape memory actuated structures, antagonistic shape memory alloy (SMA) actuators permits a fully reversible two-way response and higher response frequency. However, excessive internal stress could adversely reduce the stroke of the actuators under repeated use. The two-way shape memory effect might further decrease the range of the recovered strain under actuation of an antagonistic SMA actuator unless additional components (e.g., spring and stopper) are added to regain the overall actuation capability. In this paper, the performance of all four possible types of SMA actuation schemes is investigated in detail with emphasis on five key properties: recovered strain, cyclic degradation, response frequency, self-sensing control accuracy, and controllable maximum output. The testing parameters are chosen based on the maximization of recovered strain. Three types of these actuators are antagonistic SMA actuators, which drive with two active SMA wires in two directions. The antagonistic SMA actuator with an additional pair of springs exhibits wider displacement range, more stable performance under reuse, and faster response, although accurate control cannot be maintained under force interference. With two additional stoppers to prevent the over stretch of the spring, the results showed that the proposed structure could achieve significant improvement on all five properties. It can be concluded that, the last type actuator scheme with additional spring and stopper provide much better applicability than the other three in most conditions. The results of the performance analysis of all four SMA actuators could provide a solid basis for the practical design of SMA actuators.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.11
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• pp.1849-1855
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• 2003

Newly commercialized wireless capsule endoscope has many advantages compared to conventional push-type endoscopes. However, it is moved by the peristaltic waves. Therefore, it can not diagnose desired zones actively. In this paper, a locomotive mechanism for wireless capsule endoscope is proposed to increase the efficiency of endoscopy. We designed and fabricated a prototype using SMA springs and bio-mimetic clamping device. The hollow space in the prototype is allocated for further system integration of a camera module, a RF module and a battery. And the sequential control scheme is employed to improve the efficiency of its locomotion. To validate the performance of the locomotive mechanism, experiments on a silicone rubber pad and in vitro tests are carried out. The results of the experiments indicate that proposed mechanism is effective in harsh environments such as digestive organs of a human.

• Journal of the Korean Society of Clothing and Textiles
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• v.34 no.1
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• pp.92-101
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• 2010

This study reports on the development of intelligent clothing using a shape memory alloy (SMA) that forms a still air layer and provides thermal insulation depending on the environment temperature. SMA springs were prepared with Nitinol and have an original length of 6mm and a latent length of 20mm with a response temperature of $24.5^{\circ}C$. Hysteresis was evaluated at a temperature between $0^{\circ}C$ and $40^{\circ}C$. An experimental outdoor jacket that was attached with 30 springs was compared with a commercial jacket in terms of the microclimate temperature, humidity, and comfort properties by human subject tests in the microclimate chamber set at $5{\pm}0.5^{\circ}C$. The results showed that the microclimate temperature of SMA embedded clothing system from the wear trials was higher than the commercial ones during the rest period after exercise, especially on the skin side. In addition the thermal, humidity, and comfort sensations of SMA embedded clothing were better than the commercial ones.

• Smart Structures and Systems
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• v.3 no.1
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• pp.89-114
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• 2007

Two aspects of the design of a small-scale smart wing are addressed in this work, related to the ability of the wing to modify its cross section assuming the shape of two different airfoils and to the possibility of deflecting the profiles near the trailing edge in order to obtain hingeless control surfaces. The actuation is provided by one-way shape memory alloy wires eventually coupled to springs, Shape Memory Alloys (SMAs) being among the most promising materials for this kind of applications. The points to be actuated along the profiles and the displacements to be imposed are selecetd so that they satisfactorily approximate the change from an airfoil to the other and to result in an adequate deflection of the control surface; the actuators and their performances are designed so that an adequate wing stiffness is guaranteed, in order to prevent excessive deformations and undesired airfoil shape variations due to aerodynamic loads. The effect of the pressure distributions, calculated by way of the XFOIL software, and of the actuators loads, is estimated by FE analyses of the loaded wing. Two prototypes are then realised incorporating the variable airfoil and the hingeless aileron features respectively, and the verification of their shapes in both the actuated and non-actuated states, supported by image analysis techniques, confirms that interesting results are achievable with the proposed lay out and design considerations.