• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 1993.11a
• /
• pp.46-47
• /
• 1993

• Proceedings of the Korean Powder Metallurgy Institute Conference
• /
• 1993.11a
• /
• pp.52-53
• /
• 1993

• Proceedings of the Korean Institute of Industrial Safety Conference
• /
• 2004.04a
• /
• pp.36-41
• /
• 2004

• Proceedings of the Korean Fiber Society Conference
• /
• 2000.04a
• /
• pp.101-104
• /
• 2000

• Fashion & Textile Research Journal
• /
• v.24 no.6
• /
• pp.812-824
• /
• 2022

This study proposes to develop a 3D printed re-entrant(RE) strip by shape memory thermoplastic polyurethane that can be deformed and recovered by thermal stimulation. The most suitable 3D printing infill density condition and temperature condition during shape recovery for mechanical behavior were confirmed. As the poisson's ratio indicated, the higher the recovery temperature, the closer the poisson's ratio to zero and the better the auxetic properties. After recovery testing for five minutes, it appeared that the shape recovery ratio was the highest at 70℃. The temperature range when the shape recovery ratio appeared to be more than 90% was a recovery temperature of more than 50℃ and 60℃ when deformed under a constant load of 100 gf and 300 gf, respectively. This indicated that further deformation occurred after maximum recovery when recovered at a temperature of 80℃, which is above the glass transition temperature range. As for REstrip by infill density, a shape recovery properties of 100% was superior than 50%. Additionally, as the re-entrant structure exhibited a shape recovery ratio of more than 90%, and exhibited auxetic properties. It was confirmed that the infill density condition of 100% and the temperature condition of 70℃ are suitable for REstrips for applying the actuator.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.43 no.7
• /
• pp.635-640
• /
• 2015

In this paper, we report a non-explosive separation device for a small satellite which utilize a shape memory alloy actuator. Based on previous research, we try to increase the reliability of the proposed device by changing some components. It enables the proposed device to activate under high preload. Also, we confirm it generates low shock which is main advantage of non-explosive separation device. Finally, vibration test which mimics launching environment and thermal vacuum test which mimics space environment are carried out respectively. After each environment test, we confirm the proposed device is successfully activated. Conclusively, we develop a non-explosive separation device which can activate with low shock under high preload after shock and environment tests(vibration and thermal vacuum tests).

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.41 no.2
• /
• pp.81-85
• /
• 2017

Fiber-reinforced polymer composites, which are made by combining a continuous fiber that acts as reinforcement and a homogeneous polymeric material that acts as a host, are engineering materials with high strength and stiffness and a lightweight structure. In this study, a shape memory alloy(SMA) reinforced composite actuator is presented. This actuator is used to generate large deformations in single lightweight structures and can be used in applications requiring a high degree of adaptability to various external conditions. The proposed actuator consists of numerous individual laminas of the glass-fiber fabric that are embedded in a polymeric matrix. To characterize its deformation behavior, the composition of the actuator was changed by changing the matrix material and the number of the glass-fiber fabric layers. In addition, current of various magnitudes were applied to each actuator to study the effect of the heating of SMA wires on applying current.

• Journal of the Korean Society for Nondestructive Testing
• /
• v.24 no.3
• /
• pp.233-239
• /
• 2004

Smart material is used in various applications such as for glass frame, for medical instruments and for a part of sensors. Smart composite materials ran be applied to a part of aircraft and to the on-line monitoring system for industrial structures, using the shape memory effect. However, it is very difficult to simulate and analyze the shape memory effect in smart composites. In this paper, a two dimensional axisymmetric model was proposed to analyze the smart composite of one fiber and matrix using the finite element method(FEM). The finite element analysis was carried out in two renditions of the room temperature(293K) and a higher temperature (363K). The results we.e compared with the experimental results to confirm the validity of the analysis. In addition, the acoustic emission(AE) technique was used to study the microscopic damage behavior and the effect of pre-strains on TiNi/A16061 shape memory alloy composite.

• Journal of Aerospace System Engineering
• /
• v.12 no.2
• /
• pp.46-58
• /
• 2018

A two-axis gimbal-type X-band antenna is widely used to transmit bulk image data from high-resolution observation satellites. However, undesirable microvibrations induced by driving the antenna should be attenuated, because they are a main cause of image-quality degradation of the observation satellite. In this study, a pseudoelastic memory alloy (SMA) gear was proposed to attenuate the microvibrations by driving the antenna in an azimuth angle. In addition, the proposed gear can overcome the limitations of the conventional titanium blade gear, which is not still enough and is vulnerable to plastic deformations under excessive torque. To investigate the basic characteristics of the proposed SMA mesh washer gear, a static load test was performed on the thickness of the SMA mesh washer and the rotation of the gear. Moreover, The microvibration measurement test demonstrated that the SMA mesh washer gear proposed in this study is effective for microvibration attenuation.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.44 no.6
• /
• pp.1154-1162
• /
• 2020

In this study, the soft textile actuator is produced for a smart wearable with the shape memory effects from linear shape memory alloys of Nickel and Titanium using the driving force through the fabrication process. The measurement model was designed to measure dynamic characteristics. The heating method, and memory shape of the linear shape memory alloy were set to measure the operating temperature. A shape memory alloy at 40.13℃, was used to heat the alloy with a power supply for the selective operation and rapid reaction speed. The required amount of current was obtained by calculating the amount of heat and (considering the prevention of overheating) set to 1.3 A. The fabrication process produced a soft textile actuator using a stitching technique for linear shape memory alloys at 0.5 mm intervals in the general fabric. The dynamic characteristics of linear shape memory alloys and actuators were measured and compared. For manufactured soft textile actuators, up to 0.8 N, twice the force of the single linear shape memory alloy, 0.38 N, and the response time was measured at 50 s.