• 한국구조물진단유지관리공학회 논문집
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• 제20권1호
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• pp.72-84
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• 2016

종래 브레이스시스템은 횡력저항 및 층변위제어에 효율적이며 골조물량 감소에 따른 경제성이 향상되어 일반적인 강구조 횡력저항시스템으로 적용되고 있다. 그러나 압축측에서 항복응력에 도달하기 전 가새의 좌굴이 발생하여 충분한 내력을 발휘하지 못하고, 내력열화형의 이력거동으로 불안정상태가 된다. 좌굴에 의한 내력저하 개선시스템으로 중심재를 구속하여 좌굴방지가 가능한 비좌굴가새는 심재의 항복 이후에도 안정적인 이력특성을 나타내어 종래 브레이스에 비하여 에너지흡수능력이 우수하다. 최근 10년간 미국, 일본 및 대만에서 매우 다양한 형상의 비좌굴가새가 제안되었으나, 기존의 실험연구에서는 그 형상이 매우 제한적인 경향을 보이고 있다. 본 연구에서는 조립형 Precast RC 보강재를 가지는 비좌굴가새를 제작하고 이력특성을 평가하기 위한 부재실험을 수행하였다. 또한 실험결과를 AISC(2005)의 요구조항과 비교하였다.

• 한국체육학회지인문사회과학편
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• 제51권4호
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• pp.419-425
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• 2012

본 연구의 목적은 여자 체조선수들의 한 발 드롭 착지 시 무릎보호대가 무릎의 전방십자인대 부상 위험요인에 미치는 영향을 규명하는 것이다. 본 연구에 참가한 연구대상은 여자 체조선수 11명으로, 자신의 무릎 높이의 박스 위에서 한 발 드롭 착지 동작을 무릎보호대를 차지 않고 3번, 무릎보호대를 차고 3번씩 총 6회 무작위로 수행하였다. 무릎보호대 착용 유·무에 따른 무릎의 전방십자인대 부상 위험요인에 미치는 영향을 규명하기 위해 종속 t-test를 실시하였다. 연구결과, 여자 체조 선수들은 무릎보호대를 착용하였을 때에는 무릎보호대를 착용하지 않았을 때와 비교하여 한 발 드롭 착지 시 발목중심에서 무릎중심까지의 거리가 유의하게 더 짧게 나타났으며, 무릎의 최대 신전모멘트가 더 감소한 것으로 나타났다. 이러한 결과를 종합해 볼 때, 여자 체조선수의 한 발 드롭 착지 시 무릎보호대의 착용이 무릎의 전방십자인대에 가해지는 부하를 감소시킨 것으로 판단된다.

• 한국운동역학회지
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• 제33권2호
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• pp.73-83
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• 2023

Objective: Adolescent idiopathic scoliosis patients make up 40% of all scoliosis patients, and it is likely to increase even more because of the increase in sitting times due to the pandemic. Method: The subject of this study was a 16-year-old female student. The Cobb's Angle at initial value was 42° at the thoracic and 33° at the lumbar. The subject's height was 161.6 cm, and the type of scoliosis was 3CL. The brace was built with fabric materials with the size information from the X-ray information and actual measurements. The brace was made for the adolescents to wear for a longer time by making them put pressure on the same pressure points of the existing braces. The subjects were required to wear the device for 16 hours every day for three months. Additional features to check the pressure and time were synchronized through an app for easier communication and management with the responsible investigator. Results: After wearing the 3D Fabric brace, Cobb's angle changed from 42° to 33° at the thoracic and 33° to 23° at the lumbar. The ATR changed from 9° to 8° at the thoracic and 11° to 6° at the lumbar. As a result, the changes in the ATR angle do relate to the decrease of Cobb's angle, which made the angle of scoliosis that is bent in a three-dimensional way improve, making the height of the subject increase from 161.6 cm to 163.5 cm. Conclusion: Through this study, developing a brace that is made in the form of the 3CL to align the strap direction and putting pressure on the proper pressure points makes Cobb's angle and the ATR smaller. This means that there is a positive effect on the changes in height. A brace made of light fabric material is a good brace to help treat adolescent idiopathic scoliosis. There was an opinion that it is more comfortable to wear than existing braces, but it seems necessary to conduct a quantitative study about the before and after of wearing the brace and a survey for Korean specific cases.

• Steel and Composite Structures
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• 제19권1호
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• pp.173-190
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• 2015

This study presents an analytical investigation on the seismic response of a medium-rise buckling-restrained braced frame (BRBF) under the near-fault ground motions. A seven-story BRBF is designed as per the current code provisions for five different combinations of brace configurations and beam-column connections. Two types of brace configurations (i.e., Chevron and Double-X) are considered along with a combination of the moment-resisting and the non-moment-resisting beam-to-column connections for the study frame. Nonlinear dynamic analyses are carried out for all study frames for an ensemble of forty SAC near-fault ground motions. The main parameters evaluated are the interstory and residual drift response, brace displacement ductility, and plastic hinge mechanisms. Fragility curves are developed using log-normal probability density functions for all study frames considering the interstory drift ratio and residual drift ratio as the damage parameters. The average interstory drift response of BRBFs with Double-X brace configurations significantly exceeded the allowable drift limit of 2%. The maximum displacement ductility characteristics of BRBs is efficiently utilized under the seismic loading if these braces are arranged in the Double-X configurations instead of Chevron configurations in BRBFs located in the near-fault regions. However, BRBFs with the Double-X brace configurations exhibit the higher interstory drift and residual drift response under near-fault ground motions due to the formation of plastic hinges in the columns and beams at the intermediate story levels.

• Steel and Composite Structures
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• 제26권1호
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• pp.103-113
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• 2018

To study the effects of corner braces on fatigue performance of the U-rib and roof weld in steel bridge decks, the fatigue experiment was carried out to compare characteristics of the crack shape with and without corner braces. The improvement of fatigue life and stress variation after setting corner braces were also analysed. Different parameters of corner brace sizes, arrangements, and detail types were considered in the FEM models to obtain stress distribution and variation at the weld. Furthermore, enhancement of the fatigue performance by corner braces was evaluated. The results demonstrated that the corner brace could improve the fatigue life of the U-rib and roof weld, which exerted even no influence on the crack shape. Moreover, stress of the roof weld was decreased and the crack position was transferred from the root weld to U-rib and corner brace weld. It was suggested no weld scallop should be drilled on the corner brace. A transverse rib with lower height which was set between U-ribs was favourable for improvement of fatigue performance.

• 한국강구조학회 논문집
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• 제19권5호
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• pp.549-558
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• 2007

이 연구는 P.E.B. 골조 시스템 공장 현장에서 가장 많이 사용하고 있는 훅 볼트 형상의 골조 가새의 사용현황을 조사하여 그 문제점을 파악하기 위하여, 다양한 형상의 가새 (예를 들면, 로드 바, 로드 슈, 앵글)에 대한 구조성능실험을 실시한다. 그 실험결과의 분석, 비교를 통해서, 훅 볼트 형 가새의 기술적 한계를 평가하고, P.E.B. 골조에 적합한 인장가새의 기술을 제안한다.

• Structural Engineering and Mechanics
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• 제71권4호
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• pp.417-432
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• 2019

Seismic performance analysis of steel-brace reinforced concrete (RC) frame using topology optimization in highly seismic region was discussed in this research. Topology optimization based on truss-like material model was used, which was to minimum volume in full-stress method. Optimized bracing systems of low-rise, mid-rise and high-rise RC frames were established, and optimized bracing systems of substructure were also gained under different constraint conditions. Thereafter, different structure models based on optimized bracing systems were proposed and applied. Last, structural strength, structural stiffness, structural ductility, collapse resistant capacity, collapse probability and demolition probability were studied. Moreover, the brace buckling was discussed. The results show that bracing system of RC frame could be derived using topology optimization, and bracing system based on truss-like model could help to resolve numerical instabilities. Bracing system of topology optimization was more effective to enhance structural stiffness and strength, especially in mid-rise and high-rise frames. Moreover, bracing system of topology optimization contributes to increase collapse resistant capacity, as well as reduces collapse probability and accumulated demolition probability. However, brace buckling might weaken beneficial effects.

• PNF and Movement
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• 제20권3호
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• pp.391-397
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• 2022

Purpose: Recently, as a result of the use of smart devices, the incidence of musculoskeletal diseases in areas such as the neck and shoulders has increased. A common effect is rounded shoulder posture, which badly affects the movement and posture of the scapula, causing musculoskeletal disease. Therefore, in this study, we investigated the effects of three shoulder brace products on rounded shoulder posture. Methods: A total of 12 subjects comprising men and women in their 20s with round shoulder posture participated in this study. Three shoulder brace designs were selected, and the height change of the shoulder acromion in the lying state before and after wearing the braces was measured. Effectiveness verification was analyzed using the Mann-Whitney U test. Results: The results confirmed that the different shoulder brace designs had different effects on round shoulder posture. Conclusion: Currently, numerous designs of shoulder braces are being sold, but their effects have not been verified. In the future, more diverse designs of shoulder braces should be studied, and effective shoulder brace designs should be developed and used.

• 한국지진공학회논문집
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• 제27권2호
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• pp.101-109
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• 2023

Steel brace strengthening is the most popular seismic rehabilitation method for school buildings. This is because the design can be conducted by using relatively easy nonlinear pushover analysis and standard modeling in codes. An issue with steel brace strengthening is that the reinforced building should behave elastically to satisfy performance objectives. For this, the size of steel braces should be highly increased, which results in excessive strengthening cost by force concentration on existing members and foundations due to the considerable stiffness and strength of the steel braces. The main reason may be the brittle failure mode of columns, so this study investigated the relationship between the efficiency of steel brace strengthening and column failure modes. The result showed that the efficiency is highly dependent on the shear capacity ratio of columns and structural analysis methods. School buildings reinforced by steel braces do not need to behave elastically when the shear capacity ratio is low, and pushover analysis is used, which means reducing steel material is possible.

• 로봇학회논문지
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• 제18권2호
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• pp.189-196
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• 2023

An abdominal brace is a recommended treatment for patients with lumbar spinal disorders. However, due to the nature of the static brace, it uniformly compresses the lumbar region, which can weaken the lumbar muscles or create a psychological dependence that worsens the condition of the spine when worn for an extended period of time. Due to these issues, doctors limit the wearing time when prescribing it to patients. In this paper, we propose a device that can dynamically provide abdominal pressure and support according to the lumbar motion. The proposed device is a wearable robot in the form of a brace, with actuators and a driving unit mounted on the brace. To enhance wearability and reduce the weight of the device, worm gears actuator and a multi-pulley mechanism were adopted. Based on the spinal motion of the wearer measured by the Inertia measurement unit sensors, the drives wire by driving pulley, which provide tension to the multi-pulley mechanism on both sides, dynamically tightening or loosening the device. Finally, the device can dynamically provide abdominal pressure and support. We describe the hardware and system configuration of the device and demonstrate its potential through basic control experiments.