• Nuclear Engineering and Technology
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• v.22 no.4
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• pp.359-370
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• 1990

This study concerns with comparing low-dimensional reactor kinetics methods with a three-dimensional kinetics method to be used for safety analysis of light water reactors in order to suggest means of preparing input parameters required for low-dimensional methods. For this purpose a one-dimensional finite difference two-group diffusion theory code ODTRAN and a third-order Hermit polynomial-based point kinetics code POTRAN are developed and used to obtain low-dimensional solutions to the LRA-BWR kinetics benchmark problem. The results are compared with a three-dimensional modified Borresen's coarse-mesh solution of the kinetics problem by CMSNACK code. Through this comparison some simple but practical means of preparing input parameters of low-dimensional kinetics analysis methods are suggested.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.17 no.4
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• pp.365-374
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• 2004

Steel bridges, which have been damaged by load and corrosion, need repair or strengthening. That is a cause of decreasing the durability of structure. In order to solve these problems, welding repair and strengthening methods can be considered. In general, cutting and welding procedure is carried out during the repair welding. Therefore, the investigation of the behavior of residual stress and deformation generated by cutting and welding is very important for safety of structure. Residual stress and deformation produced by gas cutting and arc welding were analyzed using 2D and 3D thermal elasto-plastic FEM. According to the results, the magnitude of temperature was analyzed by 2D-FEM is smaller than that was analyzed using the 3D-FEM at the start and end edge of flange. And the magnitude and distribution of residual stress of perpendicular direction of the cutting line and welding line was analyzed by the 2D-FEM was similar to that was analyzed by 3D-FEM. Therefore, it is possible to predict cutting and welding residual stress by 2D and 3D FEM.

• Journal of Korea Water Resources Association
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• v.51 no.11
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• pp.971-976
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• 2018

An accurate analysis of pipeline transient is important for proper management and operation of a water distribution systems. The computational accuracy and its cost are two distinct components for unsteady flow analysis model, which can be strength and weakness of three-dimensional model and one-dimensional model, respectively. In this study, we used two-dimensional unsteady flow model with Five-Region Turbulence model (FRTM) with the implementation of interaction between liquid and air Since FRTM has an empirical component to be determined, we explored the response feature of two-dimensional flow model. The relationship between friction behaviour and the variation of undetermined parameter was configured through the comparison between numerical simulations and experimental results.

• Journal of the Korean GEO-environmental Society
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• v.16 no.8
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• pp.45-49
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• 2015

Using 2D numerical analysis that covers the largest section of the dam body, a process is generally performed when evaluating its stability against seepage. The quantity of seepage is first obtained by assuming that its bottom topography is in the simple form of a rectangle, it is then calculated by reflecting its sectional shape during this process of analyzing the seepage quantity. Considering that various forms of dams are being constructed on various types of ground, thanks to more recent technological advances, it is judged more appropriate to draw a conclusion by means of the results on reflecting the realistic shape and topographical conditions of the dam body through 3D numerical analysis. Therefore, this study intends to present a method designed to carry out safety management by evaluating the correct quantity of water leakage that passes only through the dam body, having excluded other factors that include the amount of rainfall through the 3D FEM analysis.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.770_771
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• 2009

본 논문에서는 전기강판의 2차원 교번자계 특성을 고려한 대형 영구자석 BLDC 모터의 자계 분포를 해석한다. 등방성 전기강판의 2차원 자기특성은 2차원 Single Sheet Tester를 이용하여 측정되었고, 그 결과는 확장된 B-H곡선 근사화방법을 통하여 유한요소 해석에 적용되었다. 제안된 유한요소 해석을 통하여 BLDC 모터에서의 자계 및 철손 분포가 해석되었고, 그 결과는 일반적인 유한요소 해석에 의한 결과와 비교되어진다.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.122-123
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• 2007

고전압 가스 차단기에서는 긴 스트로크 동안 가스반발력을 극복하고 빠르게 차단할 수 있는 액추에이터가 필요하다 기존에는 공압식, 유압식, 스프링 액추에이터와 같은 기계적인 장치가 사용되었다. 그러나 기존 액추에이터에서는 소음, 에너지 손실, 고가적의 단점이 있어, 근래에 들어 PMA, 모터와 같은 전기적 장치도 사용되고 있다. 전기 액추에이터는 간단한 구조로 되어 있어 기계적 손실을 줄일 수 있고 소음이 적은 장점이 있다. 전자석 조작기의 연구 필요성에 따라 새로운 형태의 전자석 조작기 Electro Magnetic Force driving Actuator(EMFA)가 개발되어 고전압 가스 차단기에 적합하다고 분석되었다. EMFA의 동특성을 얻기 위한 과도상태 해석에서는 2차원 유한요소법을 이용하여 얻은 전자기적 해석을 회로, 운동방정식과 연계하여 시간차분법을 사용하여 해석하였다. 하지만 2차원과 3차원의 전자기 해석은 차이를 보인다는 것을 확인하였고 정확한 전자기 해석을 위해 3차원 동특성 해석을 수행하여 실험결과와 비교하였다.

• Journal of Energy Engineering
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• v.6 no.2
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• pp.137-144
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• 1997

Turbulent swirling cold-flow in a cyclonic gasifier has been analyzed by numerical analysis. Comparison of two dimensional and three dimensional analyses has shown that concept of equivalent slit is appropriate for the two dimensionalization of three dimensional phenomena. Flow characteristics have been scrutinized by varying swirl number which is a crucial parameter in determining the flow pattern of the cyclonic gasifier. Reactive flow field has been estimated by using theoretical swirl number and equivalent slit width for reactive flow. Results show that proper flow field for the reactive coal gasification can be formed by controlling the exit area and azimuthal location of coal burners.

• Computational Structural Engineering
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• v.8 no.3
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• pp.91-102
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• 1995

For the wave propagation problems, the influence of time-dependent dynamic behavior must be accounted in the analysis. In this study, the dynamic analysis method which combines finite elements and boundary elements is developed for the wave propagation problem modelling the infinity of medium through 3-D boundary elements and underground structure through degenerated finite shell elements. Performing dynamic analysis of underground tunnels by the proposed coupling method of boundary and finite elements, it is found that the change of the stiffness of structures has a good effect on the response. It is also found that the consideration of the repeating effect due to moving traffic loads which is difficult with existing 2-D dynamic analysis can be possible with the 3-D analysis in time domain.

• Composites Research
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• v.28 no.4
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• pp.204-211
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• 2015

This paper presents a theory related to a two-dimensional linear cross-sectional analysis, recovery relationship and a one-dimensional nonlinear beam analysis for composite wing structure with initial twist. Using VABS including a related theory, the design process of the composite rotor blade has been described. Cross-sectional analysis was performed at cutting point including all the details of geometry and material. Stiffness matrix and mass matrix were linked to each section to make 1D beam model. The 3D strain distributions within the structure were recovered based on the global behavior of the 1D beam analysis and visualize numerical results.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.2
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• pp.235-243
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• 2010

Three-dimensional structural analysis system for nuclear containment building is presented in this paper. This system includes high-performance plate/shell elements as finite element library. It also adopts numerical modeling technique for unbonded tendon as well as bonded tendon in prestressed concrete structures. This system is constructed by connecting several in-house program to a commercial program DIANA, and then is capable of performing nonlinear analysis for ultimate pressure capacity of nuclear containment building. Finally, three-dimensional structural analysis of CANDU-type containment building is carried out in order to test the reliability of this system. These numerical results are compared with reference values, which obtained from axisymmetric structural analysis.