• International Journal of Highway Engineering
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• v.18 no.1
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• pp.73-83
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• 2016

PURPOSES : The purpose of this study is to develop a method for improving the accuracy of analysis results obtained from a two-dimensional (2-D) numerical analysis model of continuously reinforced concrete pavement (CRCP). METHODS : The analysis results from the 2-D numerical model of CRCP are compared with those from more rigorous three-dimensional (3-D) models of CRCP, and the relationships between the results are recognized. In addition, the numerical analysis results are compared with the results obtained from field experiments. By performing these comparisons, the calibration factors used for the 2-D CRCP model are determined. RESULTS : The results from the comparisons between 2-D and 3-D CRCP analyses show that with the 2-D CRCP model, concrete stresses can be overestimated significantly, and crack widths can either be underestimated or overestimated by a slight margin depending on the assumption of plane stress or plane strain. The behaviors of crack width in field measurements are comparable to those obtained from the numerical model of CRCP. CONCLUSIONS : The accuracy of analysis results from the 2-D CRCP model can be improved significantly by applying calibration factors obtained from comparisons with 3-D analyses and field experiments.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.20 no.4
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• pp.363-371
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• 2008

The aim of this study is to compare the numerical results obtained by 2-D and 3-D models which are used to examine the wave field around a permeable submerged breakwater. At first, the numerical model, which is able to consider the flow through a porous medium with inertial, laminar and turbulent resistance terms and determine the eddy viscosity with LES turbulent model, is used and validated by comparing with existing experimental data. And then, the numerical test on the wave field around a permeable submerged breakwater is performed. It is revealed from the numerical results that, at the onshore side of the submerged breakwater, the wave height by 2-D analysis is higher than that by 3-D analysis. Also, the time-averaged mean flow around a submerged breakwater is discussed in detail.

• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1287-1292
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• 2007

Recently, the frequency of unexpecting heavy rains has been increased due to abnormal climate and extreme rainfall. There was a limit to analyze 1D or 2D stream flow that was applied simple momentum equation and fixed energy conservation. Therefore, hydrodynamics flow analysis in rivers has been needed 3D numerical analysis for correct stream flow interpretation. In this study, CFD model on FLOW-3D was applied to stream flow analysis, which solves three dimenson RANS(Reynolds Averaged Navier-Stokes Equation) control equation to find out physical behavior and the effect of hydraulic structures. Numerical simulation accomplished those results was compared by using turbulence models such as ${\kappa}-{\varepsilon}$, RNG ${\kappa}-{\varepsilon}$ and LES. Those numerical analysis results have been illustrated by the turbulence energy effects, velocity of flow distributions, water level pressure distributions and eddy flows around the piers at Jangwall bridge in urbarn stream.

• Journal of Powder Materials
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• v.9 no.4
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• pp.245-250
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• 2002

In this paper we presented numerical method for the simulation of powder injection molding filling process, which is one of the key processes in powder injection molding. Rheological properties of powder binder mixture such as slip phenomena and yield stress were introduced into the numerical analysis model of powder injection molding filling simulation. Numerical model can be classified into two types. One is 2.5D model which can be introduced to a arbitrary thin geometry and the other is full 3D model which can be applied to a general 3D shape. For 2.5D model we showed the validity of our CAE system with several verification examples. Finally we suggested flow analysis model for 3D powder injection molding filling simulation.

• Journal of the Korean Society for Railway
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• v.9 no.2 s.33
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• pp.180-186
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• 2006

In this study, a large-scale laboratory model test, 2-D and 3-D numerical analyses were conducted to verify the reinforcement effect by utilizing geotextile bag on the railway roadbed. Static loading which simulated train load was applied on the geotextile bag-reinforced railway roadbed and also unreinforced railway roadbed, Computer program named Pentagon which is a part of FEM programs was used in the numerical analysis. Based on the results of laboratory test, 2-D and 3-D numerical analyses, the effect of load distribution and settlement reduction was found to be depending on the geotextile characteristics, tensile strength of geotextite, and interface friction angle between geotextile bags. In general, the result of 2-D and 3-D numerical analyses shows lower value than that of laboratory test. Also, the result of 3-D numerical analyses shows lower value than that of 2-D numerical analyses because of its stress transfer effect.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.3
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• pp.859-871
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• 2014

In order to analyze the density current due to salt and temperature difference, this study develops new numerical model (LES-WASS-3D ver. 2.0) by introducing state equation for salt and temperature and 3D advection-diffusion equation to existing 3D numerical wave tank (LES-WASS-3D ver. 1.0). To verify the applicability, the newly-developed numerical model is analyzed comparing to the experimental result of existing numerical model. In the result, it well implement the behavior and vertical salt concentration of advected and diffused seawater as well as flow velocity and temperature of the discharged warm water. This confirms the validity and effectiveness of the developed numerical model.

• Journal of Advanced Research in Ocean Engineering
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• v.1 no.2
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• pp.115-133
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• 2015

This paper describes an approach for the numerical analysis of container ship slamming and whipping and various parameters that influence slamming and whipping. For validation purposes, the numerical analysis results were compared with experimental results obtained as part of the Wave-Induced Loads on Ships Joint Industry Project. Water entry problems for two-dimensional (2D) sections were first solved using a 2D generalized Wagner model (GWM) for various drop conditions and geometries. As the next step, the hydroelastic numerical analysis of a 10,000-TEU container ship subjected to slamming and whipping loads in waves was performed. The analysis method used is based on a fully coupled model consisting of a three-dimensional (3D) Rankine panel model, a 3D finite element model (FEM), and a 2D GWM, which are strongly coupled in the time domain. Parametric studies were carried out in both numerical and experimental tests with various forward speeds, wave heights, and wave periods. The trends observed and the validity of the numerical analysis results are discussed.

• Steel and Composite Structures
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• v.15 no.3
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• pp.247-266
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• 2013

This paper presents a comparison of results obtained by a newly developed numerical model for predicting the behaviour of structures under fire with experimental study carried out on heated and simply supported steel beam elements. A newly developed numerical model consists of three submodels: 3D beam model designed for calculating the inner forces in the structure, 2D model designed for calculation of stress and strain distribution over the cross section, including the section stiffness, and 3D transient nonlinear heat transfer model that is capable of calculating the temperature distribution along the structure, and the distribution over the cross section as well. Predictions of the calculated temperatures and vertical deflections obtained by the numerical model are compared with the results of the inhouse experiment in which steel beam element under load was heated for 90 minutes.

• Wind and Structures
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• v.7 no.1
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• pp.13-28
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• 2004

A method of numerical analysis without conducting 3D wind tunnel model tests was examined in our previous study for predicting vortex-induced oscillation of bridge girders with span-wise varying geometry. The aerodynamic damping forces measured for plural wind tunnel 2D models were used in the analysis. A further study was conducted to examine the precision of solution obtained by this method. First, the responses of vortex-induced oscillation of two rocking models and a taut-strip bridge girder model with span-wise varying geometry were measured. Next, the responses of these models were numerically analyzed by means of this method, and then a comparison was made between the obtained $Vr-A-{\delta}_a$ contour diagram of each 3D model in the wind tunnel test and the diagram in the numerical analysis. Since close correlations were observed between each two $Vr-A-{\delta}_a$diagrams obtained in the model test and in the analysis in cases where the 3D model did not have strong three-dimensionality, our findings revealed that the predicted solution proved to be reasonably accurate.

• Tunnel and Underground Space
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• v.22 no.2
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• pp.93-105
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• 2012

This paper compares the two- and three-dimensional (2D and 3D) approaches for the numerical determination of the equivalent mechanical properties of fractured rock masses. Both orthogonally-fractured model and discrete fracture networks (DFN) were used for the geometry and 2D models were cut in various directions from 3D model to compare their mechanical properties. Geological data were loosely based on the data available from Sellafield, UK. Analytical method based on compliance tensor transformation was used for investigation in orthogonally fractured rock and numerical experiments were conducted on fractured rock mass with DFN geometry. It is shown that 2D approach always overestimates the elastic modulus of fractured rock masses by a factor of up to around two because fractures are assumed to be perpendicular to the model plane in 2D problems. Poisson ratios tend to have larger values in 2D analysis while there is opposite trend in some sections. The study quantitatively demonstrates the limitation of the 2D approach that uses the simplified model from true 3D geometry.