• Steel and Composite Structures
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• 제35권2호
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• pp.237-247
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• 2020

Shear connectors are essential elements in the design of steel-concrete composite systems. These connectors are utilized to prevent the occurrence of potential slips at the interface of steel and concrete. The two types of shear connectors which have been recently employed in construction projects are C- and L-shaped connectors. In the current study, the behavior of C and L-shaped angle shear connectors is investigated experimentally. For this purpose, eight push-out tests were composed and subjected to monotonic loading. The load-slip curves and failure modes have been determined. Also, the shear strength of the connectors has been compared with previously developed relationships. Two failure modes of shear connectors were observed: 1) concrete crushing-splitting and 2) shear connector fracture. It was found that the L-shaped connectors have less shear strength compared to C-shaped connectors, and decreasing the angle leg size increases the shear strength of the C-shaped connectors, but decreases the relative ductility and strength of L-shaped connectors.

• Ocean Systems Engineering
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• 제9권1호
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• pp.21-42
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• 2019

In this paper, the Finite-Analytic Navier-Stokes (FANS) code is coupled with an in-house finite-element code to study the dynamic interaction between a floating buoy and its mooring system. Hydrodynamic loads on the buoy are predicted with the FANS module, in which Large Eddy Simulation (LES) is used as the turbulence model. The mooring lines are modeled based on a slender body theory. Their dynamic responses are simulated with a nonlinear finite element module, MOORING3D. The two modules are coupled by transferring the forces and displacements of the buoy and its mooring system at their connections through an interface module. A free-decay model test was used to calibrate the coupled method. In addition, to investigate the capability of the present coupled method, numerical simulations of two degree-of-freedom vortex-induced motion of a CALM buoy in uniform currents were performed. With the study it can be verified that accurate predictions of the motion responses and tension responses of the CALM buoy system can be made with the coupling CFD-FEM method.

• 대한방사선기술학회지:방사선기술과학
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• 제42권3호
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• pp.195-199
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• 2019

Most of the vascular procedures performed for various diagnoses and treatments of various abdominal intervention procedures performed by the Department of Radiology and Angiography are performed by puncture of the femoral artery. For this reason, patients should undergo blood-related tests such as prothrombin time (PT) and partial thromboplatin time (PTT). Therefore, many patients are instructed to take precautions such as putting a sandbag on the puncture site to prevent delayed hemorrhage after hemostasis of the femoral artery puncture site, and not to bend the leg of the treated area for about 3 hours. Because of this, many patients have complained of pain during the procedure and inconvenience during the absolute bed rest time in the ward. The purpose of this study was to compare the safety of balloon ancillary devices with sandbags placed on the hemostasis site to prevent delayed hemorrhage after arterial puncture. We compared the safety of each patient with the results of medical records in consideration of the problem that the patient could not press with the focus, the position of the patient was changed depending on the patient's body shape, and the problem of falling down according to the location of the puncture site. As a result, the use of a balloon type ancillary device improves the effect of continuous hemostasis, reduces discomfort during the patient's absolute stabilization time, increases the patient's satisfaction, and is a good alternative to the existing sandbag.

• Ocean Systems Engineering
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• 제9권3호
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• pp.219-240
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• 2019

This paper presents the comparison between SFT response with linear and nonlinear cables. The dynamic response analysis of submerged floating tunnel (SFT) is presented computationally with linear and nonlinear tension legs cables. The analysis is performed computationally for two wave directions one at 90 degrees (perpendicular) to tunnel and other at 45 degrees to the tunnel. The tension legs or cables are assumed as linear and non- linear and the analysis is also performed by assuming one tension leg or cable is failed. The Response Amplitude Operators (RAO's) are computed for first order waves, second order waves for both failure and non-failure case of cables. For first order waves- the SFT response is higher for sway and heave degree of freedom with nonlinear cables as compared with linear cables. For second order waves the SFT response in sway degree of freedom is bit higher response with linear cables as compared with nonlinear cables and the SFT in heave degree of freedom has higher response at low time periods with nonlinear cables as compared with linear cables. For irregular waves the power spectral densities (PSD's) has been computed for sway and heave degrees of freedom, at $45^0$ wave direction PSD's are higher with linear cables as compared with nonlinear cables and at $90^0$ wave direction the PSD's are higher with non-linear cables. The mooring force responses are also computed in y and z directions for linear and nonlinear cables.

• Earthquakes and Structures
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• 제16권1호
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• pp.119-127
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• 2019

When a structural wall is subjected to multi-directional ground motion, torsion-induced cracks degrade the stiffness of the wall. The effect of torsion should not be neglected. As a main lateral load resisting member, reinforced concrete (RC) structural wall has been widely studied under the combined action of bending and shear. Unfortunately, its seismic behavior under a combined action of torsion, bending and shear is rarely studied. In this study, torsional performances of the RC structural walls under the combined action is assessed from a comprehensive parametrical study. Finite element (FE) models are built and calibrated by comparing with the available experimental data. The study is then carried out to find out the critical design parameter affecting the torsional stiffness of RC structural walls, including the axial load ratio, aspect ratio, leg-thickness ratio, eccentricity of lateral force, longitudinal reinforcement ratio and transverse reinforcement ratio. Besides, to facilitate the application in practice, an empirical equation is developed to estimate the torsional stiffness of RC rectangular structural walls conveniently, which is found to agree well with the numerical results of the developed FE models.

• 생명과학회지
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• 제19권7호
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• pp.968-975
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• 2009

본 연구에서는 8주의 유산소 및 저항성 트레이닝 그룹으로 나누고 그에 따른 트레이닝이 서로 다른 테스트를 하였을 때, 운동 특이성 효과(specific effect)와 전사효과(transferabilty)에 영향을 미치는 지를 연구하였다. 결론적으로 8주간의 유산소 및 저항성 트레이닝은 동일한 테스트를 통하여 운동의 특이성은 나타냈으나 서로 다른 테스트를 해 봄으로써 전사효과의 향상은 나타내지 못했다. 전사효과를 나타내지 못한 가장 큰 이유는 8주라는 기간이 중추신경과 근육의 적응하기에는 다소 짧은 기간이라 사료되며 추후의 연구에서는 트레이닝 기간등을 고려한 좀 더 세분화된 연구가 필요하다고 생각된다.

• Ocean Systems Engineering
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• 제6권2호
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• pp.143-159
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• 2016

Cargo, such as a Tension Leg Platform (TLP), Semi-submersible platform (Semi), Spar or a circular Floating Production Storage and Offloading (FPSO), are frequently dry-transported on a Heavy Lift Vessel (HLV) from the point of construction to the point of installation. The voyage can span months and the overhanging portions of the hull can be subject to frequent wave slamming events in rough weather. Tie-downs or sea-fastening are usually provided to ensure the safety of the cargo during the voyage and to keep the extreme responses of the cargo, primarily for the installed equipment and facilities, within the design limits. The proper design of the tie-down is dependent on the accurate prediction of the wave slamming loads the cargo will experience during the voyage. This is a difficult task and model testing is a widely accepted and adopted method to obtain reliable sea-fastening loads and extreme accelerations. However, it is crucial to realize the difference in the inherent stiffness of the instrument that is used to measure the tri-axial sea fastening loads and the prototype design of the tie-downs. It is practically not possible to scale the tri-axial load measuring instrument stiffness to reflect the real tie-down stiffness during tests. A correlation method is required to systematically and consistently account for the stiffness differences and correct the measured results. Direct application of the measured load tends to be conservative and lead to over-design that can reflect on the overall cost and schedule of the project. The objective here is to employ the established correlation method to provide proper high-frequency responses to topsides and hull design teams. In addition, guidance for optimizing tie-down design to avoid damage to the installed equipment, facilities and structural members can be provided.

• Steel and Composite Structures
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• 제35권3호
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• pp.305-325
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• 2020

Beams of steel frame-tube structures (SFTSs) typically have span-to-depth ratios of less than five. This makes a flexural beam unsuitable for such an application because the plastic hinges at the beam-ends cannot be adequately developed. This leads to lower ductility and energy dissipation capacities of SFTSs. To address this, SFTSs with bolted web-connected replaceable shear links (SFTS-BWSLs) are proposed. In this structural system, a web-connected replaceable shear link with a back-to-back double channel section is placed at the mid-length of the deep beam to act as a ductile fuse. This allows energy from earthquakes to be dissipated through link shear deformation. SFTS and SFTS-BWSL buildings were examined in this study. Several sub-structures were selected from each designed building and finite element models were established to study their respective hysteretic performance. The seismic behavior of each designed building was observed through static and dynamic analyses. The results indicate that the SFTS-BWSL and SFTS have similar initial lateral stiffness and shear leg properties. The SFTS-BWSL had lower strength, but higher ductility and energy dissipation capacities. Compared to the SFTS, the SFTS-BWSL had lower interstory drift, base shear force, and story shear force during earthquakes. This design approach could concentrate plasticity on the shear link while maintaining the residual interstory drift at less than 0.5%. The SFTS-BWSL is a reliable resistant system that can be repaired by replacing shear links damaged due to earthquakes.

• 한국게임학회 논문지
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• 제11권6호
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• pp.33-42
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• 2011

본 연구에서는 신체의 장애를 반영한 복지형 게임디자인 틀을 제시하였다. 이 게임 디자인 방식은 게임 규칙의 관용성과 게임의 환경적 체감을 노인의 선택적 반응능력과 같은 민첩성에 적절하도록 제작하는 것을 의미한다. 그리고 복지형 게임방식을 적용하고, 하지근육의 개선과 균형조절능력의 향상을 목표로 '굴렁쇠 굴리기 밸런스게임'을 개발하였다. 게임진행은 양발의 굴림 동작과 양손의 누름동작으로 의자형 게임컨트롤러에 설치된 압력센서를 누르는 단순한 동작으로 진행하며 복합동작이 필요하지 않도록 하였다. 또한 게임그래픽의 소재로서 회상요법으로 활용되고 있는 나마지와 하인즈(1994)에 의해 제시된 지각자극 세트를 활용하여 노인들에게 친숙한 게임그래픽으로 구성하였다. 노인 50명을 대상으로 테스트진행하고 설문조사하였다. 설문조사의 결과로 74%가 게임에 만족한다고 답하였고, 88%가 게임을 지속적으로 게임을 이용하겠다는 유의미한 결과를 얻었다.

• Steel and Composite Structures
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• 제12권1호
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• pp.31-51
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• 2012

Local buckling can be ignored for hot-rolled ordinary strength steel equal angle compression members, because the width-to-thickness ratios of the leg don't exceed the limit value. With the development of steel structures, Q420 high strength steel angles with the nominal yield strength of 420 MPa have begun to be widely used in China. Because of the high strength, the limit value of the width-to-thickness ratio becomes smaller than that of ordinary steel strength, which causes that the width-to-thickness ratios of some hot-rolled steel angle sections exceed the limit value. Consequently, local buckling must be considered for 420 MPa steel equal angles under axial compression. The existing research on the local buckling of high strength steel members under axial compression is briefly summarized, and it shows that there is lack of study on the local buckling of high strength steel equal angles under axial compression. Aiming at the local buckling of high strength steel angles, this paper conducts an axial compression experiment of 420MPa high strength steel equal angles, including 15 stub columns. The test results are compared with the corresponding design methods in ANSI/AISC 360-05 and Eurocode 3. Then a finite element model is developed to analyze the local buckling behavior of high strength steel equal angles under axial compression, and validated by the test results. Following the validation, a finite element parametric study is conducted to study the influences of a range of parameters, and the analysis results are compared with the design strengths by ANSI/AISC 360-05 and Eurocode 3.