• Title/Summary/Keyword: Coupled Analysis

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Structural Design of Coupled RC Structural Wall Considering Plastic Behavior (소성거동을 고려한 병렬 RC 구조벽체시스템의 설계)

  • Yu, Seung-Yoon;Eom, Tae-Sung;Kang, Su-Min
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.30 no.4
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    • pp.351-361
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    • 2017
  • Reinforced concrete(RC) structural walls are major lateral load-resisting structural member in building structures. Generally these RC structural walls are coupled with each other by the coupling beams and slabs, and therefore they behave as RC coupled structural wall system. In the design of these coupled structural wall systems, member forces are calculated using elastic structural analysis. These elastic analysis methodologies for the design of coupled structural wall system was not reasonable because it can not consider their ultimate behavior and assure economic feasibility. Performance based design and moment redistribution method to solve these problems is regarded as a reasonable alternative design method for RC coupled structural wall system. However, it is not verified under various design parameters. In this study, nonlinear analysis of RC coupled structural wall system was performed according to various design parameters such as reinforcement ratio, ultimate concrete strain and wall height. Based on analysis results, design considerations for coupled RC structural wall system was proposed.

Analysis and Design of Coupled Inductors for Two-Phase Interleaved DC-DC Converters

  • Lee, Jong-Pil;Cha, Honnyong;Shin, Dongsul;Lee, Kyoung-Jun;Yoo, Dong-Wook;Yoo, Ji-Yoon
    • Journal of Power Electronics
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    • v.13 no.3
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    • pp.339-348
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    • 2013
  • Multiphase dc-dc converters are widely used in modern power electronics applications due to their advantages over single-phase converters. Such advantages include reduced current stress in both the switching devices and passive elements, reduced output current ripple, and so on. Although the output current ripple of a converter can be significantly reduced by virtue of the interleaving effect, the inductor current ripple cannot be reduced even with the interleaving PWM method. One way to solve this problem is to use a coupled inductor. However, care must be taken in designing the coupled inductor to maximize its performances. In this paper, a detailed analysis of a coupled inductor is conducted and the effect of a coupled inductor on current ripple reduction is investigated extensively. From this analysis, a UU core based coupled inductor structure is proposed to maximize the performance of the coupled inductor.

Hydroelastic Effects in Vibration of Plate and Ship Hull Structures Contacted with Fluid

  • Lee, Jong-Soo;Song, Chang-Yong
    • International Journal of Ocean System Engineering
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    • v.1 no.2
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    • pp.76-88
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    • 2011
  • The present study deals with the hydroelastic vibration analysis of structures in contact with fluid via coupled fluid-structure interaction (FSI) embedded with a finite element method (FEM) such that a structure displacement formulation is coupled with a fluid pressure-displacement formulation. For the preliminary study and validation of FEM based coupled FSI analysis, hydroelastic vibration characteristics of a rectangular plate in contact with fluid are first compared with the elastic vibration in terms of boundary condition and mode frequency. Numerical results from coupled FSI analysis have been shown to be rational and accurate, compared to energy method based theoretical solutions and experimental results. The effect of free surface on the vibration mode is numerically studied by changing the submerged depth of a rectangular plate. As a practical application, the hull structural vibration of 4,000 twenty-foot equivalent units (TEU) container ship is considered. Hydroelastic results of the ship hull structure are compared with those obtained from the elastic condition.

A Study of Coupled Electromagnetic-Thermal Field Analysis for Temperature Rise Prediction of Power Transformer (전력용 변압기의 온도상승 예측을 위한 전자계-열계 결합해석기법 연구)

  • Ahn, Hyun-Mo;Kim, Min-Soo;Song, Jae-Sung;Hahn, Sung-Chin
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.10
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    • pp.1838-1845
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    • 2011
  • This paper deals with coupled electromagnetic-thermal field analysis for thermal fluid analysis of oil immersed power transformer. Electric power losses are calculated from electromagnetic field analysis and are used as input source of thermal field analysis based on computational fluid dynamics(CFD). Particularly, In order to accurately predict the temperature rise in oil immersed power transformer, the thermal problem should be coupled with the electromagnetic problem. Moreover, to reduce analysis region, the heat transfer coefficient is applied to boundary surface of the power transformer model. The coupling method results are compared with the experimental values for verifying the validity of the analysis. The predicted temperature rises show good agreements with the experimental values.

Coupled Load Analysis Using MSC/Nastran Superelement (MSC/Nastran Superelement를 이용한 연성하중해석)

  • Kim, Gyeong-Won;Kim, Jin-Hui;Lee, Ju-Hun;Kim, Seon-Won
    • Aerospace Engineering and Technology
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    • v.5 no.2
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    • pp.60-66
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    • 2006
  • This paper is a study on the coupled load analysis using MSC/Nastran superelement method. After selecting the hunch vehicle, coupled load analysis is performed. From the results of coupled load analysis the loads and displacements on the major parts of satellite structure are calculated Based on the loads and displacements, the safety of satellite structure is judged. Coupled load analysis has been executed using MSC/Nastran DMAP code so far. Because DMAP code was very complicated and long in 1ength it was difficult to analyze and modify the DMAP code. To solve out these problems, coupled load analysis was executed using MSC/Nastran 2005 superelemnt method. At first, satellite FE-model was converted to the Craig-Bampton model using MSC/Nastran 2005 superelement method and verified Finally, coupled load analysis was performed using satellite Craig-Bampton model and launch vehicle FE-model and verified.

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Coupled Effect of Pile/Slope Systems (억지말뚝-사면의 상호작용 효과)

  • 정상섬;유광호;이선근
    • Journal of the Korean Geotechnical Society
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    • v.19 no.5
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    • pp.163-173
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    • 2003
  • In this paper, a numerical comparison of predictions by limit equilibrium analysis and 3D analysis is presented for slope/pile system. Special attention is given to the coupled analysis based on the explicit finite difference code, FLAC 3D. To this end, an internal routine (FISH) was developed to calculate a factor of safety for a file reinforced slope according to shear strength reduction technique. The case of coupled analyses was performed for stabilizing piles in slope in which the pile response and slope stability are considered simultaneously. In this study, by using these methods, the failure surfaces and factors of safety were compared and analyzed in several cases, such as toe, middle and top of the slope, respectively. Furthermore, the coupled method based on shear strength reduction technique was verified by the comparison with other analysis results.

3D coupled analysis on tunneling under groundwater (지하수가 터널굴착에 미치는 영향에 관한 3차원 연계해석)

  • Yoo, Chung-Sik
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.5 no.2
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    • pp.175-187
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    • 2003
  • This paper presents the effect of groundwater on tunnel performance. Fundamental issues in tunneling under high groundwater table together with an illustrative example are discussed. The effect of groundwater on tunnel excavation was examined using a 3D stress-pore pressure coupled finite-element analysis. The results of the 3D coupled analysis were then compared with those of a total stress analysis. Examined items included earth and pore pressures around lining, and lining stresses. Also the examined include face movement and ground surface movements. The results indicated that the effect of groundwater on tunnel excavation can only be captured through a fully coupled analysis. Implementations of the findings from this study are discussed in great detail.

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HOT CHANNEL ANALYSIS CAPABILITY OF THE BEST-ESTIMATE MULTI-DIMENSIONAL SYSTEM CODE, MARS 3.0

  • JEONG J.-J.;BAE S. W.;HWANG D. H.;LEE W. J.;CHUNG B. D.
    • Nuclear Engineering and Technology
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    • v.37 no.5
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    • pp.469-478
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    • 2005
  • The subchannel analysis capability of MARS, a multi-dimensional thermal-hydraulic system code, has been enhanced. In particular, the turbulent mixing and void drift models for the flow-mixing phenomena in rod bundles were improved. Then, the subchannel analysis feature was combined with the existing coupled system thermal-hydraulics (T/H) and 3D reactor kinetics calculation capability of MARS. These features allow for more realistic simulations of both the hot channel behavior and the global system T/H behavior. Using the coupled features of MARS, a coupled analysis of a main steam line break (MSLB) is carried out for demonstration purposes. The results of the calculations are very reasonable and promising.

Investigation on Interaction between Tunneling and Groundwater (터널시공과 지하수의 상호작용 고찰)

  • Yoo, Chung-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.415-424
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    • 2004
  • This paper presents the effect of groundwater on tunneling performance. The interaction between the tunneling and groundwater was examined using a 3D stress-pore pressure coupled finite-element analysis, The results of the 3D coupled analysis were then compared with those of a total stress analysis. Examined items included pore pressures around lining and lining forces. Also examined include face displacements and ground surface movements, The results indicated that the interaction between the tunneling and ground water significantly increases the lining forces and ground deformations, and that the effect of ground water on tunneling can only be captured through a fully coupled analysis, Implementations of the findings from this study arc discussed in great detail.

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