• Title, Summary, Keyword: 수치해석

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Flow Analysis around inclined Crest Groyne for 3-D Numerical Simulation (수리 및 3차원 수치모형을 이용한 경사형 수제주변 흐름해석)

  • Yeo, Hong-Koo;Kang, Joon-Gu;Kim, Sung-Jung
    • Proceedings of the Korea Water Resources Association Conference
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    • pp.1229-1233
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    • 2007
  • 국내에서의 수제는 하안 및 제방의 보호, 유로제어 및 주운 등의 목적에 의해 설치되기 보다는 수제로 인해 발생되는 수제역(recirculation zone)의 다양한 흐름이 수중생물의 다양한 서식처 및 홍수 시 어류의 피난처 제공한다는 환경적인 목적이 지배적이다. 따라서 홍수시 하천의 통수능 감소영향이 상대적으로 작고 국부세굴에 대해 안정적인 경사형 수제에 대한 관심이 크며 몇몇 곳에서는 시공되어 졌다. 하지만 경사수제에 대한 설계기법은 현재 미미한 상태이며 선행되어져야할 구조물 주변의 흐름해석에 관한 연구도 미미하다. 이에 본 연구에서는 3차원 수치모형을 적용하여 주수로와 수제역의 흐름해석을 수행하였다. 연구내용은 수리모형변화와 수치모형실험을 병행하여 수행하여 수치모형결과를 검증하였으며 그 결과를 적용하여 경사형 수제주변의 흐름을 해석하였다. 수치모형은 Flow 3D모형을 이용하여 경사형 수제조건에 따른 흐름해석을 수행하였고 수리모형실험은 수치모형과 동일한 2가지 조건에 대해 수행하여 수치모형결과와 비교 분석 하였다. 본 연구의 목적은 경사형 수제설치로 변화되는 수제역 흐름을 3D 수치해석으로 분석하여 수제역의 환경적 효과(수중생물의 서식처 등)에 대한 기초자료를 제공하는 것이다. 연구결과, 수치모형실험은 수리모형결과와 일치하였으며 경사형 수제특성에 따라 수심별 흐름변화를 분석할 수 있었으며 기존 불투과 및 투과수제와 다른 결과를 도출하였다.

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On the Dynamic Analysis of Cables for ROV Implementation (무인 잠수정 연결 케이블의 동적거동 해석에 관한 연구)

  • Yi, Woo-Sup
    • Journal of Ocean Engineering and Technology
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    • v.5 no.1
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    • pp.45-54
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    • 1991
  • 본 논문은 케이블-ROV 시스템의 동적거동 규명을 위한 효과적인 해석방법에 대한 고찰이다. 해석방법에 대하여 일차적으로 연구하고 해석방법에 따른 소프트웨어를 개발하여 3차원 케이블-ROV 시스템 거동을 수치적으로 해석하였으며 같은 모델에 대한 거동을 실제 실험을 통하여 연구분석 하였다. 수치해석과 실험결과를 비교 검토하였고 여러가지 관련 문제점에 대해서도 연구하였다.

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Numerical Analysis of Steel-strengthened Concrete Panels Exposed to Effects of Blast Wave and Fragment Impact Load Using Multi-solver Coupling (폭풍파 및 파편 충돌에 대한 강판보강 콘크리트 패널의 복합적 수치해석)

  • Yun, Sung-Hwan;Park, Taehyo
    • Journal of The Korean Society of Civil Engineers
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    • v.31 no.1A
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    • pp.25-33
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    • 2011
  • The impact damage behavior of steel-strengthened concrete panels exposed to explosive loading is investigated. Since real explosion experiments require the vast costs to facilities as well as the blast and impact damage mechanisms are too complicated, numerical analysis has lately become a subject of special attention. However, for engineering problems involving blast wave and fragment impact, there is no single numerical method that is appropriate to the various problems. In order to evaluate the retrofit performance of a steel-strengthened concrete panel subject to blast wave and fragment impact loading, an explicit analysis program, AUTODYN is used in this work. The multi-solver coupling methods such as Euler-Lagrange and SPH-Lagrange coupling method in order to improve efficiency and accuracy of numerical analysis is implemented. The simplified and idealized two dimensional and axisymmetric models are used in order to obtain a reasonable computation running time. As a result of the analysis, concrete panels subject to either blast wave or fragment impact loading without the steel plate are shown the scabbing and perforation. The perforation can be prevented by concrete panels reinforced with steel plate. The numerical results show good agreement with the results of the experiments.

Numerical Analysis of Magnetic Flux Leakage Inspection (누설자속탐상의 수치해석)

  • Lee, Hyang-Beom;Kim, Sean
    • Journal of the Korean Society for Nondestructive Testing
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    • v.21 no.5
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    • pp.485-492
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    • 2001
  • In this paper, electro-magnetic numerical analysis of MFL(magnetic flux leakage) method is presented. For the electromagnetic numerical analysis, 2-D FEM(finite element method) is used. The magnetic vector potential is used as a variable. The analysis of the magnetic field considering the magnetic nonlinearity is performed for the effect of the magnetic salutation. For the verification of the validity of the numerical simulation results, by using the lab-made experimental setup, non-destructive inspection is performed. The SM 45C carbon steel is used as a specimen and the artificial defects are made on the specimen. The non-destructive testing for the detection of the defect is performed. The results according to the variation oi the defect depth and the defect shape are obtained. The experimental results are compared to the numerical ones, and we conclude that the numerical results are similar to the experimental ones. So the possibility of simulation of the MFL by using the numerical analysis is shown in this paper.

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Numerical Analysis of Wave Impact Forces in Numerical Wave Basin (수치파 수조를 이용한 파랑 충격력 수치해석)

  • Shin, Young-Seop;Hong, Key-Yong
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • v.1
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    • pp.205-210
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    • 2006
  • The impact forces of the highly nonlinear waves are one of the important factors in designing the ocean structures. The impact forces are very difficult to analyze numerically and experimentally because they are impulsive in magnitude and occur instantaneously. In this study the numerical program based on N.S. equations are used to investigate the impact forces of steep waves where the waves are gene rated by the wave maker in the numerical wave basin. The arbitrary steep waves are generated by the superposition of waves of single frequency and the impact forces on vertical cylinder are simulated on the multiblock grids. V.O.F. and the local height function methods are used to track the free surfaces. To validate the numerical analysis the numerical results are compared with the experimental ones and the acceptable agreements are found. It is thought that more studies on the simulations of the incoming breaking waves and the impact forces on the vertical cylinder should be made to obtain the useful results to be applied in the offshore design.

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A Intercomparison on the estimating shield TBM tunnel face pressure through analytical and numerical analysis (이론해와 수치해석적 검토를 통한 쉴드TBM 막장압 산정 결과 상호비교)

  • Jun, Gy-Chan;Kim, Dong-Hyun
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.18 no.3
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    • pp.273-282
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    • 2016
  • This study estimates tunnel face pressure through existing 8 analytical equations and 3D numerical analysis, and compares and examines it. In general, the estimating tunnel face pressure of domestic shield TBM has been examined by a method according to analytical equation and empirical method, but numerical analysis is combined in a section passing complicated stratigraphic condition and special soil condition. Therefore, the researcher is to find a reliable method to examine of tunnel face pressure by confirming a correlation between tunnel face pressure estimated by equation and tunnel face pressure estimated by numerical analysis program. When tunnel face pressure is estimated, both analytical equation and numerical analysis were identically examined in soil conditions such as sandy soil and cohesive soil. In addition, existing analytical equation is used as equation, and 3D analysis copying construction process and shield tunnel as numerical analysis.

A Study for Thermal Mechanism of Residential Combustibles with Numerical Modeling (주거공간 단위가연물의 열역학적 수치해석 모델링에 관한 연구)

  • Ahn, Chan-Sol;Kim, Jung-Yup;You, Yong-Ho;Kweon, Oh-Sang;Joo, Sang-Hyun
    • Fire Science and Engineering
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    • v.25 no.6
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    • pp.58-63
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    • 2011
  • This study is intended to present a computational thermal model for the combustibles in a residential building. As the Performance Based Design is more popular, fire-intensity and fire-load have turned out to be very important factors for building design and can be predicted through some computational work. To predict and estimate the thermal properties of the residential combustible fire, we made some numerical models of combustibles in a residential building. In a bid to validate the estimate values, computational analysis results from numerical models were compared with real fire tests. For computational analysis, the Fire Dynamics Simulator was used with Large Eddy Simulation model for turbulence. Consequently, each heat release rate and total heat release curves were successfully estimated.

Vibration Analysis of the Beam Structure with a Moving Mass (이동물체에 의한 보 구조물의 진동 해석)

  • 이우식;임강민
    • Computational Structural Engineering
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    • v.8 no.4
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    • pp.57-64
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    • 1995
  • This paper introduced a simple numerical analysis algorithm for the calculation of the dynamic responses of the beam structure with a moving mass. The dynamic equation of motion of the Bernoulli-Euler beam is derived by considering the moving mass as a moving particle, and the dynamic equation of motion is transformed into an integro-differential equation by use of the structural influence function. The numerical solutions of the integro-differential equation are obtained by the modal analysis approach, and compared with those cited from well-known references. The proves that the numerical analysis algorithm proposed herein provide very reliable results, and thus it can be utilized in the design analysis of the beamlike structures exited by a mass which is traveling on it.

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Numerical analysis of rock behavior with crack model implementation (균열모형을 이용한 암석거동의 수치해석)

  • 전석원
    • Tunnel and Underground Space
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    • v.9 no.1
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    • pp.56-63
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    • 1999
  • Rock behaves in a complex way due to the discontinuities. To describe the complicated failure and deformation behavior of rock, many researches were focused on the development of crack models. This study discusses the validity of the sliding and shear crack model to systematically fractured rock, i.e. coal. The model was also implemented into a numerical analysis. For that, a finite element program was modified in several ways. To describe the transverse isotropy in two-dimensional analysis, the stress-strain relationship was modified for the direction of the axis of symmetry. Also, the changes of the effective elastic moduli according to the crack growth were calculated. A simple example of two-dimensional laboratory uniaxial compression test was analyzed. The results coincided with the observations obtained from the laboratory tests.

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A Study of Shape Finding of Equally Stressed Surface for Membrane Structures by Dynamic Relaxation Method (동적이완법에 의한 막구조의 등장력곡면 형태해석에 관한 연구)

  • 한상을;이경수
    • Computational Structural Engineering
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    • v.11 no.4
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    • pp.321-330
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    • 1998
  • 막구조의 초기형상을 결정하기 위하여 막요소의 기하학적 비선형을 고려한 평형방정식을 유도하고, 등장력곡면(equally stressed surface)을 결정하기 위한 알고리즘을 정식화한다. 막구조는 대변형에 의한 기하학적 비선형성을 포함하고, 막구조의 특성상 초기장력에 의한 초기변형을 고려해야 하므로, 본 논문에서는 막구조와 같은 인장구조물의 비선형 수치해석을 수행하기 위한 해석기법으로써, 동적이완법(Dynamic Relaxation Method)에 대한 해석알고리즘을 적용하고, 이 방법에 의해 수행한 해석결과를 검토함으로써 막구조 해석에 적용 가능한 수치해석기법을 제시하고, 수치해석에 대한 예를 통해 본 해석법의 타당성을 검증한다.

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