• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.4 s.175
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• pp.982-990
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• 2000

The finite element alternating method is extended further for general three dimensional cracks in an isotropic body subjected to the mode I loading. The required analytical solution for a dime dimensional crack in an infinite isotropic body is obtained by solving the integral equations. In order to remove the high singularity in integration, the technique suggested by Keat et al. was used. With the proposed method several example problems are solved in order to check the accuracy and efficiency of the method.

• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.738-741
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• 2004

This study is concerning on modeling to predict the flexural behaviors of FRP-confined concrete structural members. For compressive behaviors of confined concrete by FRP jackets, the hypoelasticity-based constitutive law of concrete has been presented under the basis of three-dimensional stress states. The strength enhancement of concrete wrapped by FRP jackets has been determined by the failure surface of concrete in tri-axial states, and its corresponding peak strain is computed by the strain enhancement factor. The behavior of FRP jackets has been modeled using the mechanics of orthotropic laminated composite materials in two-dimensional stress states. To be based on the three-dimensional constitutive laws, an algorithm for the prediction of flexural bending behaviors of FRP-confined concrete structural member has been presented.

• Journal of Biosystems Engineering
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• v.17 no.1
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• pp.37-44
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• 1992

This study was intended to develop the design program of the working surface of moldboard-plow by use of the computer-aided design. The mathematical model of the working surfaces of moldboard-plows by use of computer graphics was developed and plotted in two dimension on three major planes. The surfaces of moldboard-plows were represented with "B-spline surface fitting" by selecting the twenty-five three-dimensional data that could well describe the working surface of moldboard-plow. The shape of moldboard-plow on three major planes was drawn for varied design parameters. The representation of the mathematical model for the working surfaces of various types of moldboard-plows was manipulated by translation, rotation and scaling about arbitrary axes in space. By using three-dimensional graphics techique to describe moldboard-plows, it was capable of plotting the three-dimensional shape of moldboard-plow easily and quickly in comparison with the existing design methods that were difficult to grasp the shape of moldboard-plow as a whole. The design theories of moldboard plow and three-dimensional computer graphic technique were applied to find out the improved reversible Jaenggi bottom. It was resulted in the newly developed shape of Jaenggi which may be used for improving the performance compared to existing ones.

• Journal of Korean Society for Geospatial Information Science
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• v.21 no.4
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• pp.135-142
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• 2013

This study aims to seek adequate and optimized method of applying high quality three-dimensional spatial data created via high-resolution digital aerial photograph image and aerial LiDAR data onto three-dimensional planning of environmentally friendly, ecological restoration of rivers in accordance with irrigation and flood control objectives of urban rivers. Through three-dimensional modeling of before and after the restoration, the research also offers basic information regarding restorations of rivers. Also the transition from the conventional two-dimensional planning into three-dimensional planning environment using smart spatial information acquire accuracy of river analysis, analyze possible civil complaints and suggest solutions to potential problems.

• Journal of Institute of Control, Robotics and Systems
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• v.8 no.3
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• pp.208-219
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• 2002

A novel measurement method to obtain the 6-DOF motions of arbitrary rigid bodies is proposed in this paper. The method adopts a specially fabricated mirror called 3-facet mirror, which looks like a triangular pyramid haying an equilateral cross-sectional shape. The mirror is mounted on the objects to be measured, illuminated by a laser beam having circular profile, and reflects the laser beam in three different directions. Three PSDs(position sensitive detector) detect the three beams reflected by the mirror, respectively. From the signals of the PSDs, we can calculate the 3-dimensional position and orientation of the 3-facet mirror, and thus enabling us to determine the 3-dimensional position and orientation of the objects. In this paper, we model the relationship between the 3-dimensional position and orientation of an object in motion and the outputs of three PSDs. A series of experiments are performed to demonstrate the effectiveness and accuracy of the proposed method. The experimental results show that the proposed sensing system can be an effective means of obtaining 3-dimensional position and orientation of arbitrary objects and provide resonable measurement accuracy.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2001.05a
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• pp.16-19
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• 2001

Rapid Prototyping (RP) and Rapid Tooling (RT) were introduced to reduce time-to-market and cost by shortening not only the development phase but also the production phase of the manufacturing process. RP generally builds up a prototype layer by layer, rapidly generating a fully three-dimensional free form shape. RT enables the manufacture of production tools. The integration of RP and RT has the potential for rapid net shaping of thee-dimensional parts, which have geometrical complexity. In this study, net shaping techniques for making three-dimensional parts using RP and RT are described and a sample part are shown. A three-dimensional metal part is manufactured by a new RP process, Variable Lamination Manufacturing by using Expandable Polystyrene Foam (VLM-S), and its application to RT for making a clover punch. In addition, we discussed the technology fusion between metal forming md RP/RT.

• Journal of the Korea institute for structural maintenance and inspection
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• v.4 no.2
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• pp.113-129
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• 2000

This study evaluates the behavior and strength of an anchorage zone of the prestressed concrete box girder bridge on the Kyungboo highway railroad using the 2D SUB-3D STM approach and a linear elastic finite element analysis. The 2D SUB-3D STM approach utilizes several two-dimensional sub strut-tie models that represent the compressive and tensile stress flows of each projected plane of the three-dimensional structural concrete in the selection of a three dimensional strut-tie model, evaluation of the effective strengths of the concrete struts, and verification of the geometric compatibility condition and bearing capacity of the critical nodal zones in the selected three-dimensional strut-tie model. The finite element analysis uses an 8-node brick element and the longitudinal prestressing force is considered as the equivalent nodal force. Analysis results show that the 2D SUB-3D STM approach and linear elastic finite element method can be effectively applied to the analysis and design of three-dimensional structural concrete including a prestressed concrete box girder anchorage zone.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2006.11a
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• pp.431-434
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• 2006

This study reviews the properties of coastal ocean and Seomjin River estuary spaces then define some MGIS(Marine Geographic Information System) related terminologies for clarifying the scope of MGIS boundaries. Therefore, we show the three-dimensional circulation of MGIS-based Seomjin River Estuary integrating three-dimensional POM model and observed data.

• Nuclear Engineering and Technology
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• v.42 no.3
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• pp.279-296
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• 2010

For the analysis of transient two-phase flows in nuclear reactor components, a three-dimensional thermal hydraulics code, named CUPID, has been developed. The CUPID code adopts a two-fluid, three-field model for two-phase flows, and the governing equations were solved over unstructured grids, which are very useful for the analysis of flows in complicated geometries. To obtain numerical solutions, the semi-implicit numerical method for the REALP5 code was modified for an application to unstructured grids, and it has been further improved for enhanced accuracy and fast running. For the verification of the CUPID code, a set of conceptual problems and experiments were simulated. This paper presents the flow model, the numerical solution method, and the results of the preliminary assessment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.3 s.246
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• pp.222-229
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• 2006

Three dimensional turbulent flow in the scroll volute of centrifugal compressor has been numerically investigated in this paper by solving the Navier-Stokes equations and $\kappa-\varepsilon$ equation model. The computational grid for the flow field of the scroll volute has been constructed based on the multi-block grid concept, which is good to avoid the central grid singularity as well as to promote grid stretching toward the volute wall. Numerical result has been obtained for both the two- and three- dimensions. For the latter flow, result of the scroll volute flow is compared with that of the straight conical volute. This comparison has sorted out the characteristic features of the three-dimensional scroll-type volute flow of centrifugal compressor.