• Title, Summary, Keyword: Structure

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VORTEX STRUCTURE IN THE SCOUR HOLE BY GATE OPENING OF HYDRAULIC STRUCTURE

  • Kim, Jin-Hong;Choe, Jae-Wan
    • Water Engineering Research
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    • v.1 no.1
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    • pp.83-92
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    • 2000
  • Jet flow can occur by gate opening at downstream of a hydraulic structure such as weir of drainage gate. If the stream bed is not hard or the bed protection is not sufficient, vortex erosion occurs and a resulting scour hole will be formed due to the high shear stress of the jet flow. Once the scour hole is formed, a vortex occurs in ti and this vortex causes additional erosion. If this erosion continues and reaches to the hydraulic structure, it can undermine the bottom of the hydraulic structure and this will lead to failure of the structure itself. Thus, it is necessary to define the physical features of the vortex structure in the scour hole for the design of the bed protection. This study presents the turbulent vortex structure in the scour hole by the gate opening of the hydraulic structure. Characteristics of vortex motion, circulation, vortex scale and vortex were analyzed through experiments. Experimental results of the vortex velocity were compared with theoretical ones. From these, circulation and vortex scale were obtained with known values of inflow depth, inflow velocity and scale of scour hole

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A Study on The Structural Systems of Modern Architecture and Architectural Characteristics (근대건축의 구조시스템과 건축적 특성에 관한 연구)

  • Cho, Sung-Hyun
    • Journal of The Korean Digital Architecture Interior Association
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    • v.10 no.1
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    • pp.49-56
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    • 2010
  • The purpose of this study is to examine the relationship between the structural system used in modern architecture and the form and spatial composition of the buildings. The principle in stabilization of structures is closely related to the architectural form. That is, in order to stabilize a building, a special type of structural system is required and consequently shows up with consistent characteristics in the architectural form. Modern architecture can be classified into skeleton structure, trusses structure, and space structure according to the structural characteristics. Skeleton structure is then divided into a perpendicular form and tapered form. Trusses structure is categorized as dome-shaped structure and slab-shaped structure, and space structure can be divided into compressible space structure and tensile space structure. When classifies the modern building with the aspect of architectural effect, there is a possibility of trying to divide with effect of production, and its expression. Effect of production mean structural system and effect of expression mean space and plan.

A Study on a Development of Hybrid(Magnesium & Steel) Structure for Application of Cockpit Module (Cockpit Module용 Hybrid Structure개발에 관한 연구)

  • 박병구;이정환;김영삼;한성수
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.6
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    • pp.166-170
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    • 2002
  • A hybrid structure composed of magnesium and steel is Instrument Panel structure used for the basement of cockpit module components. For that reason, A hybrid structure has to be designed for satisfying components assembly design facility and styling. There are various models of If like steel structure assembly, however having been applied normally, but magnesium structure assembly selected far saving weight down. This paper introduces a hybrid structure having advantages between steel and magnesium structure and presents a CAE technical solution based on a development project. furthermore, it provides desired direction of the future development is suggested.

Evaluation of Effective Stiffness for 3D Beam with Repeated Structure (반복 구조로 구성된 3차원 보의 유효 강성 계산)

  • Chung Ilsup
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.7
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    • pp.170-176
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    • 2005
  • Analysis of structures which are composed of numerous repeated unit structures can be simplified by using homogenized properties. If the unit structure is repeated in one direction, the whole structure may be regarded as a beam. Once the effective stiffness is obtained from the analysis of the unit structure in a proper way, the effort for the detail modeling of the global structure is not required, and the real structure can be replaced simply with a beam. This study proposes a kinematical periodicity constraint to be imposed on the FE model of the unit structure, which improves the accuracy of the effective stiffness. The method is employed to a one dimensionally arrayed 3D structure containing periodically repeated un-symmetric holes. It is demonstrated that the deformation behavior of the homogenized beam agrees well with that of the real structure.

Structure-soil-structure interaction in a group of buildings using 3D nonlinear analyses

  • Sharifi, Behroozeh;Nouri, Gholamreza;Ghanbari, Ali
    • Earthquakes and Structures
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    • v.18 no.6
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    • pp.667-675
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    • 2020
  • The current study compares the effect of structure-soil-structure interaction (SSSI) on the dynamic responses of adjacent buildings and isolated structures including soil-structure interaction (SSI) with the responses of fixed-base structures. Structural responses such as the relative acceleration, displacement, drift and shear force were considered under earthquake ground motion excitation. For this purpose, 5-, 10- and 15-story structures with 2-bay moment resisting frames resting on shallow foundations were modeled as a group of buildings in soft soil media. Viscous lateral boundaries and interface elements were applied to the soil model to simulate semi-infinite soil media, frictional contact and probable slip under seismic excitation. The direct method was employed for fully nonlinear time-history dynamic analysis in OpenSees using 3D finite element soil-structure models with different building positions. The results showed that the responses of the grouped structures were strongly influenced by the adjacent structures. The responses were as much as 4 times greater for drift and 2.3 times greater for shear force than the responses of fixed-base models.

SOME STRUCTURES ON A COMPLETE LATTICE

  • Lee, Seung On;Yon, Yong Ho
    • Journal of the Chungcheong Mathematical Society
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    • v.20 no.3
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    • pp.211-221
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    • 2007
  • In this paper, we define ${\bigwedge}$-structure, ${\bigvee}$-structure to generalize some lattices, and study the conditions that a lattice which has ${\bigwedge}$-structure or ${\bigvee}$-structure to be continuous or algebraic.

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Capital Structure Adjustment in Korean Retail Firms

  • Kim, Sang-Su;Lee, Jeong-Hwan
    • Journal of Distribution Science
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    • v.15 no.11
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    • pp.41-48
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    • 2017
  • Purpose - Capital structure adjustment costs influence the test of the standard trade-off theory of capital structure. We investigate whether there exist economically significant capital adjustment costs in the Korean retail industry. Research design, data, and methodology - This paper adopts the model of Leary and Roberts(2005) to obtain the hazard rate of capital structure variations. The retail firms traded in the KOSPI and KOSDAQ markets are analyzed from 2000 to 2016. Results - The empirical analysis shows infrequent capital structure adjustments in the Korean retail firms. The duration analysis emphasizes that the fixed adjustment cost plays an important role in the determination of capital structure adjustments for the Korean retail firms. Yet, even after taking account of infrequent capital structure adjustments, the trade off theory only weakly explains the capital structure variations of the Korean retail firms. Conclusions - This paper confirms the existence of capital structure adjustment costs for the Korean retail firms. Our results argue for the significance of fixed adjustment costs in capital structure adjustments. Such emphasis on the fixed cost is inconsistent with the existing studies. The trade off theory does not successfully explain capital structure policy in the Korean retail firms even after considering adjustment costs.

Seismic Response of Arch Structure Subjected to Different Ground Motion (상이한 지반조건을 갖는 아치구조물의 지진응답 분석)

  • Kim, Gee-Cheol;Kang, Joo-Won
    • Journal of Korean Association for Spatial Structures
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    • v.13 no.1
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    • pp.113-119
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    • 2013
  • Spatial structures have the different dynamic characteristics from general rahmen structures. Therefore, it is necessary to accurately analyze dynamic characteristics and seismic response of spatial structure for seismic design of spatial structure. An arch structure is used as an example structure because it has primary characteristics of spatial structures. Multiple support excitation may be subjected to supports of a spatial structure because ground condition of spatial structures is different. In this study, the response analysis of the arch structure under multiple support excitation and simple support excitation is studied. By means of the pseudo excitation method, the seismic response is analyzed for long span spatial structure. It shows that the structural response is divided into two parts, ground displacement and structural dynamic response due to ground motion excitation. It is known that the seismic response of spatial structure under multiple support excitation and simple support excitation are the different in some case. Therefore, it has to be necessary to analyze the seismic response of spatial structure under multiple support excitation because the spatial structure supports may be different.

A study on the optimal configuration of harbor structure under the combined loads

  • Cho, Kyu-Nam
    • Structural Engineering and Mechanics
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    • v.32 no.3
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    • pp.371-382
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    • 2009
  • Response of harbor structure to environmental loads such as wave load, impact load, ship's contacting load, is a fundamental factor in designing of the structure's optimal configuration. In this paper, typical environmental loads against coastal structures are investigated for designing of the optimal harbor structure. Loads to be considered here are wave load, impact load and contacting load due to ship mooring. Statistical analysis for several harbor structure types under the corresponding loads is carried out, followed by investigation of effect of individual environmental load. Based on these, the optimal configuration for the harbor structure is obtained after considerable engineering process. Estimation of contacting load of the ship is suggested using effective energy concepts for the load, and analysis of structural behavior is done for the optimal designing of the structure in the particular load. A guideline for the design process of the harbor structure is established, and safety of the structure is examined by proposed scheme. For verification of the analytical approach, various steel-piled coastal structures and caissons are chosen and relevant structural analyses are carried out using the Finite Element Methods combined with MIDAS/GTS and ANSYS code. It is found using the Morison equation that impact load cannot be a major load in the typical harbor structure compared with the original wave load, and that configuration shape of the structure may play an important role in consideration of the response criteria.