• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.353-356
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• 2004

Nonlinear numerical analysis was performed to investigate the behavioral characteristics and failure mechanism of flexure -dominated structural walls with partially confined boundary elements. Based on the results, deformability of walls with partially confined boundary elements was evaluated, and a design method which can determine depth of confined boundary element according to given ductility demand, was developed. Also, effective details of laterally confining re-bars were proposed for boundary elements with rectangular cross-section. The design method can be used to choose the spacing of confining re-bars assuring the confining effect and constructability.

• 대한설비공학회지:설비저널
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• 제15권4호
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• pp.388-395
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• 1986

Numerical solutions of two-dimensional, steady, and natural are investigated in a confined rectangular cavity with porous media. The saturated fluid is bounded by two isothermal vertical walls at different temperatures and two adiabatic horizontal walls. Governing equations are numerically solved by finite difference method with the up wind scheme. Distributions of streamline and temperature we. predicted for aspect ratios ranging from 0.1 to 1.0, Rayleigh numbers 50 to $10^4$, and tilt angles $0^{\circ}\;to\;60^{\circ}$. Representative plots of temperature and velocity field according to tilt angle are presented. The effects of aspect ratio, Rayleigh number, and tilt angle on local and average Nusselt numbers are obtained. The optimum conditions for maximum Nusselt number are also presented with tilt angles.

• 한국지진공학회논문집
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• 제20권4호
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• pp.211-222
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• 2016

Reinforced concrete shear walls with deficient reinforcement details are tested under cyclic loading. The deficiency of reinforcement details includes insufficient splice length in U-stirrups at the ends of horizontal reinforcement and boundary column dowel bars found in existing low- to mid-rise Korean buildings designed non-seismically. Three test specimens have rectangular, babel and flanged sections, respectively. Flexure- and shear-controlled models for reinforced concrete shear walls specified in ASCE/SEI 41-13 are compared with the flexural and shear components of force-displacement relation extracted separately from the top displacement of the specimen based on the displacement data measured at diverse locations. Modification of the shear wall models in ASCE/SEI 41-13 is proposed in order to account for the effect of bar slip, cracking loads in flexure and shear. The proposed modification shows better approximation of the test results compared to the original models.

• 한국지진공학회논문집
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• 제19권5호
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• pp.229-238
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• 2015

For small-size reinforce-concrete buildings, Midas Gen, OpenSees, and Perform-3D, which are structural analysis programs that are most popularly used at present, were applied for nonlinear static pushover analysis, and then difference between those programs was analyzed. Example buildings were limited to 2-story frames with irregular shaped walls. Analysis result showed that there were more differences than for frames only and frames with rectangular walls, but it was not so significant. Nevertheless, the capacity curve were different in some buildings, which is attributed to shape and location of walls, and feature of the analysis program. Especially, selection of automatic or manual input in Midas Gen, or nonlinear wall elements in Perform3D can affect the capacity curve and performance of the buildings. Therefore, the program users should understand the feature of the program well, and then conduct performance assessment. The result of this study is limited to low-story buildings so that it should be noted that it is possible to get different results for mid- to high-rise buildings.

• Steel and Composite Structures
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• 제32권3호
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• pp.337-346
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• 2019

The present paper tries to contribute fill the gap of application of the component method to tubular connections. For this purpose, one typical joint configuration in which just one component can be considered as active has been studied. These joints were selected as symmetrically loaded welded connections in which the beam width was the same as the column width. This focused the study on the component 'side walls of rectangular hollow sections (RHS) in tension/compression'. It should be one of the main components to be considered in welded unstiffened joints between I beams and RHS columns. Many experimental tests on double-sided I-beam-to-RHS-column joint with a width ratio 1 have been carried out by the authors and a finite element (FE) model was validated with their results. Then, some different analytical approaches for the component stiffness and strength have been assessed. Finally, the stiffness proposals have been compared with some FE simulations on I-beam-to-RHS-column joints. This work finally proposes the most adequate equations that were found for the stiffness and strength characterization of the component 'side walls of RHS in tension/compression' to be applied in a further unified global proposal for the application of the component method to RHS.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2803-2810
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• 2007

Three dimensional numerical studies were carried out to investigate the effect of aspect ratio on gas slip flow in rectangular microchannels. We focused on aspect ratio effect on slip velocity, pressure distribution and mass flow rate. As aspect ratio decreases the wall slip velocity also decreases. As a result nonlinearity of pressure distribution increases. The slip velocities on sides and top/bottom walls are different and this difference decreases with increasing aspect ratio. These two velocities are equal when aspect ratio is 1. The ratios of slip mass flow rate over noslip mass flow rate increases with increasing aspect ratios.

• Wind and Structures
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• 제14권5호
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• pp.449-463
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• 2011

Drag forces on a rectangular louvered panel, both as a free-standing structure and as a component in a generic low-rise building model, were obtained in a wind tunnel study. When tested in a building model, the porosity ratio of the wall opposite the louvered panel was varied to investigate its effect on the loading of the louvered panel. Both mean and pseudo-steady drag coefficients were obtained. Comparisons with the provisions for porous walls in contemporary loading standards indicate that for some opposite wall porosity ratios, the standards specify significantly different wind loads (larger and smaller) than obtained from this wind tunnel study.

• 동력기계공학회지
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• 제4권2호
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• pp.11-16
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• 2000

Simultaneous quantitative measurements are made of the velocity fields for two-dimensional natural convection in a rectangular enclosure using PIV(Particle Image Velocimetry). The experiments are performed at a Prandtl number of 6.62, an aspect ratio of 1.0, Rayleigh numbers from $1.294{\times}10^6\;to\;3.8841{\times}10^6$, and angles of inclination of $0^{\circ},\;30^{\circ}\;and\;60^{\circ}$ inside a $30mm{\times}30mm{\times}8mm$ cavity made of an acrylic glass 10mm, with two isothermal copper walls kept at a prescribed temperature. The experimental results agreed very well with the numerical results. It was found that the flow consisted of a large double convection cell at angle of inclination of $60^{\circ}$.

• 태양에너지
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• 제10권1호
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• pp.31-37
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• 1990

사각관로의 축대칭 공동부내의 흐름에 대하이 실험적으로 연구를 하였다. 공동부의 측벽과 대향벽에서 압력과 전달계수를 측정하였다. 공동부의 길이는 80mm에서 ${\infty}$로 변화시켰을때 재부착점을 지나서 공동부의 길이를 증가시킨 경우 열전달계수는 감소하였고, 재부착점 근방에서 평균 열전달계수가 최대치가 됨을 얻었다.

• 설비공학논문집
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• 제7권4호
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• pp.547-555
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• 1995

Melting process of ice in a rectangular cavity with different temperature walls has been studied experimentally. Front shape of ice and melting rate were affected by initial temperature of ice and variation of temperature distribution and density gradient. When the hot wall temperature was below $8^{\circ}C$, the melting rates were higher at the bottom than those of at the top due to the density inversion, but with increasing the hot wall temperature the melting rates at the top were affected by hot wall and were higher than those of at the bottom. When the initial temperature of ice was low, melting rates were low, but with increasing the time melting rates were almost the same with those of each initial temperature of ice.