• Title/Summary/Keyword: 3-D numerical simulation

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Characteristics of Run-up Height over Sandy Beach with Submerged Breakwaters : PART I - Effect of Plane Arrangement of Submerged Breakwaters (잠제 설치 연안의 처오름 높이 특성 : PART I - 잠제의 평면배치에 의한 영향)

  • Hur, Dong-Soo;Lee, Woo-Dong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.3B
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    • pp.345-354
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    • 2008
  • In this present study, we made a first attempt to investigate physical transformations of incident waves in surf and swash zone and hydrodynamic phenomena of detached and submerged breakwaters. For an accurate simulation of the complicated wave deformation, Three-Dimensional numerical model with Large Eddy Simulation has been developed recently and expanded properly for the current applications, which is able to simulate an accurate and direct WAve Structure Sandy seabed interaction (hereafter, LES-WASS-3D). LES-WASS-3D has been validated through the comparison with experimental results for limited cases, and has been used for the simulation of wave run-up on sandy beach, mean fluid flows over and around submerged structures and swash zone (alongshore/rip current), and spatial distribution of wave height in wide fluid regions. In addition, a strategy of efficient deployment ($Y/L_i=1.50{\sim}1.75$, $W/L_r=0.50$) of the submerged breakwaters has been discussed.

Characteristics of Run-up Height over Sandy Beach with Submerged Breakwaters ; PART II - Effect of Shape of Submerged Breakwaters (잠제 설치 연안의 처오름 높이 특성 ; PART II - 잠제의 제원에 의한 영향)

  • Hur, Dong-Soo;Lee, Woo-Dong
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.4B
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    • pp.429-439
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    • 2008
  • The purpose of this study is to examine the characteristics of run-up height over sandy beach due to the shape of submerged breakwater. For the discussion on it in detail, 3-Dimensional numerical model with Large Eddy Simulation, which is able to simulate directly interaction of Wave Structure Sandy beach (hereafter, LES-WASS-3D; Hur and Lee, 2007) has been used to simulate run-up height over sandy beach as well as wave field around submerged breakwaters. Using the results obtained from numerical simulation, the effects of the shape of submerged breakwaters (crown height, crown width, crown length and submerged breakwater's slope gradient) on run-up height over sandy beach have been discussed related to the wave height distribution and characteristics of up-layer flow around ones.

Numerical Study on Variation of Penetration Performance into Concrete with Reinforcement Modeling Methods (철근 모사 방법에 따른 콘크리트 관통성능 변화에 관한 수치적 연구)

  • Baek, Seung-Ju
    • Journal of the Korea Society for Simulation
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    • v.25 no.3
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    • pp.97-105
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    • 2016
  • This paper discusses the effect of numerical reinforcement modeling methods on the penetration performance of a penetrator into a concrete target. AUTODYN-3D has been used to conduct the numerical penetration analyses. In order to validate the computational approach, experimental data of Hanchak have been compared to a computation result and a reasonably good agreement could be obtained. The strength and the diameter of a reinforcement have been changed to find out the effect of reinforcement modeling methods on the penetration performance. The impact locations and velocities of a penetrator are also changed to investigate the effect of reinforcement modeling methods. Residual velocities of a penetrator are quantitatively compared in detail for the evaluation of reinforcement modeling effects on the penetration performance.

Experimental and Numerical Simulation Studies of Low-Velocity Impact Responses on Sandwich Panels for a BIMODAL Tram

  • Lee, Jae-Youl;Shin, Kwang-Bok;Jeong, Jong-Cheol
    • Advanced Composite Materials
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    • v.18 no.1
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    • pp.1-20
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    • 2009
  • This paper describes the results of experiments and numerical simulation studies on the impact and indentation damage created by low-velocity impact subjected onto honeycomb sandwich panels for application to the BIMODAL tram. The test panels were subjected to low-velocity impact loading using an instrumented testing machine at six energy levels. Contact force histories as a function of time were evaluated and compared. The extent of the damage and depth of the permanent indentation was measured quantitatively using a 3-dimensional scanner. An explicit finite element analysis based on LS-DYNA3D was focused on the introduction of a material damage model and numerical simulation of low-velocity impact responses on honeycomb sandwich panels. Extensive material testing was conducted to determine the input parameters for the metallic and composite face-sheet materials and the effective equivalent damage model for the orthotropic honeycomb core material. Good agreement was obtained between numerical and experimental results; in particular, the numerical simulation was able to predict impact damage area and the depth of indentation of honeycomb sandwich composite panels created by the impact loading.

Wind tunnel tests and CFD simulations for snow redistribution on 3D stepped flat roofs

  • Yu, Zhixiang;Zhu, Fu;Cao, Ruizhou;Chen, Xiaoxiao;Zhao, Lei;Zhao, Shichun
    • Wind and Structures
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    • v.28 no.1
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    • pp.31-47
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    • 2019
  • The accurate prediction of snow distributions under the wind action on roofs plays an important role in designing structures in civil engineering in regions with heavy snowfall. Affected by some factors such as building shapes, sizes and layouts, the snow drifting on roofs shows more three-dimensional characteristics. Thus, the research on three-dimensional snow distribution is needed. Firstly, four groups of stepped flat roofs are designed, of which the width-height ratio is 3, 4, 5 and 6. Silica sand with average radius of 0.1 mm is used to model the snow particles and then the wind tunnel test of snow drifting on stepped flat roofs is carried out. 3D scanning is used to obtain the snow distribution after the test is finished and the mean mass transport rate is calculated. Next, the wind velocity and duration is determined for numerical simulations based on similarity criteria. The adaptive-mesh method based on radial basis function (RBF) interpolation is used to simulate the dynamic change of snow phase boundary on lower roofs and then a time-marching analysis of steady snow drifting is conducted. The overall trend of numerical results are generally consistent with the wind tunnel tests and field measurements, which validate the accuracy of the numerical simulation. The combination between the wind tunnel test and CFD simulation for three-dimensional typical roofs can provide certain reference to the prediction of the distribution of snow loads on typical roofs.

Scale Effects of Initial Model and Material on 3-Dimensional Distinct Element Simulation (3차원 개별요소해석 시의 초기 모델 및 재료 스케일 영향)

  • Jeon, Jesung;Shin, Donghoon;Ha, Iksoo
    • Journal of the Korean GEO-environmental Society
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    • v.12 no.7
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    • pp.57-65
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    • 2011
  • Numerical simulations by three-dimensional Particle Flow Code($PFC^{3D}$, Itasca) considering distinct element method (DEM) were carried out for prediction of triaxial compression test with sand material. The effect of scale conditions for numerical model and distinct material on final prediction results was analyzed by numerical models under various scale conditions, and following observations were made from the numerical experiments. It is very useful to model the initial material condition without any porosity conversion from 2-D to 3-D DEM. Numerical experiments have shown that in all cases considered, 3D distinct element modeling could provide good agreement on stress-strain behavior, volume change and strength properties with laboratory testing results. It was important thing to assess reasonable scale ratio of numerical model and distinct elements for saving calculation time and securing calculation efficiency under condition with accuracy and appropriateness as numerical laboratory. As results of DEM simulations under various scale conditions, most of results show that shear strength properties as cohesion and internal friction angle are similar in condition of $D_{mod}/D_{gmax}$ < 10. It shows that 3-D distinct element method could be used as efficient tool to assess strength properties by numerical laboratory technique.

Spatial and temporal distribution of driving rain on a low-rise building

  • Blocken, Bert;Carmeliet, Jan
    • Wind and Structures
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    • v.5 no.5
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    • pp.441-462
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    • 2002
  • This paper presents a practical numerical method to determine both the spatial and temporal distribution of driving rain on buildings. It is based on an existing numerical simulation technique and uses the building geometry and climatic data at the building site as input. The method is applied to determine the 3D spatial and temporal distribution of wind-driven rain on the facade a low-rise building of complex geometry. Distinct wetting patterns are found. The important causes giving rise to these particular patterns are identified : (1) sweeping of raindrops towards vertical building edges, (2) sweeping of raindrops towards top edges, (3) shelter effect by various roof overhang configurations. The comparison of the numerical results with full-scale measurements in both space and time for a number of on site recorded rain events shows the numerical method to yield accurate results.

Impact Analysis of Motorcycle Helmet (모터싸이클 헬멧의 충격 해석)

  • Thai, Huu-Tai;Kim, Seung-Eock
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2008.04a
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    • pp.573-578
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    • 2008
  • Finite element analysis of impact response of a motorcycle helmet is presented in this paper. The finite element LS-DYNA3D code is used to simulate the impact response of the helmet including of plastic shell, foam liner, and magnesium headform. Since the maximum accelerations at center of gravity of the headform obtained by numerical analysis and experiment agree well, the numerical simulation is proved to be valid.

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