• Geotechnical Engineering
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• v.12 no.6
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• pp.127-138
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• 1996

The in-situ consolidation behavior of drainage system-installed deposits has three dimensional characteristics. Therefore, for an approximate 2-D plane strain consolidation analysis, it is necessary to convert the 3-D spatial flow of actual cases into the laminar flow simulated by the 2-D plane strain model. . In this paper, in order to properly model the effect of three dimensional characteristics, an equivalent and efficient model has been applied in a finite element technique for the analysis of the drainage system-installed soil deposits. The equivalent two dimensional model involves equivalent permeabilities and drainage widths. To validate the equivalent two dimensional model, three dimensional analyses were per formed by using the ABAQUS program and the results of 3-D analyses were compared with those of the 2-D analyses. By using the proposed equivalent model, one may be able to appropriately predict the consolidation behavior of drainage system-installed soft deposits.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.5
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• pp.421-428
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• 2009

In this study, an equivalent plate element model has been developed for an efficient vibration analysis of a biaxial hollow slab. To this end, equivalent mass and stiffness of equivalent plate element models corresponding to solid element models of example biaxial hollow slabs were calculated. To verify the efficiency and accuracy of the equivalent plate element models, structural analyses of example structures were performed. Analytical results showed that the natural frequencies of the equivalent plate element models were very close to those of the solid element models. Time history analyses of example biaxial hollow slabs subjected to walking load were conducted using the equivalent plate element models and the solid element models, and the results were compared. It could be seen based on the analytical results that the equivalent plate element model could provide very accurate results compared to the solid element model with significantly reduced analysis time.

• 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.

• Journal of the Korean GEO-environmental Society
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• v.11 no.11
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• pp.5-18
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• 2010

In this paper, a 3-dimensional stiffened plate model for soil-metal box structures is proposed. 3-dimensional stiffened plate model is enable to model corrugated steel plates of soil metal box culverts considering section modulus and section properties of longitudinal and horizontal direction from a corrugated steel plate. Loading conditions which causes maximum displacement and maximum moment according to the step construction stages(a back filling to the top of the plate, a back filling to the maximum depth of cover, and loading of live loads) was applied and the behaviors of the soil metal box culverts was analyzed. Analysis results of 3-dimensional stiffened model were compared with those of 2-dimensional model, 3-dimensional equivalent plate model and 3-dimensional corrugated plate model. As results, the behaviors of 2-dimensional model and 3 dimensional equivalent model are different from 3-dimensional corrugated plate model but the result of 3-dimensional stiffened model has good agreement with that of 3-dimensional corrugated plate model.

• Proceedings of the Korean Geotechical Society Conference
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• 1995.03a
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• pp.3-14
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• 1995

• Journal of the Korean Society for Precision Engineering
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• v.20 no.5
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• pp.57-65
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• 2003

The formation of exit burr in drilling metals is analyzed by finite element method. The simplified burr formation model is suggested for the complex mechanism of burr formation in drilling on the basis of experimental data. Using the model the magnitude of burr is predicted and the effect of material properties of workpiece and cutting condition on burr formation is analyzed in the present study. The suggested model is verified by comparing simulation results and experimental ones. The predicted size and shape of burr are in good agreement with those observed by experiment.

• Journal of the Korean Magnetics Society
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• v.20 no.3
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• pp.100-105
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• 2010

For predicting magnetic signals due to the remanent magnetization distributed on a ferromagnetic ship hull, this paper presents an efficient methodology for solving inverse problems, where the material sensitivity analysis based on the continuum mechanics is combined with the equivalent magnetic models. To achieve this, the 3D magnetic charge model and the magnetic dipole moment model are introduced and material sensitivity formulae applicable to each equivalent model are derived. The formulae offer the first-order gradient information of an objective function with respect to the variation of the magnetic charge or magnetic dipole and so an optimal solution can be easily obtained regardless of the number of design variables. To validate the proposed method, the numerical results are comparison with the real measurements of a mock-up model.

• Journal of the Korean Vacuum Society
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• v.3 no.4
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• pp.457-465
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• 1994

유도결합 플라즈마의 해석식으로 양극성 확산, 정상상태를 가정한 확산식, 열평형식과 변위전류 를 무시한 맥스웰 식을 사용하였다. 해석기법으로는 유한 차분법과 적분법을 축대칭 2차원(R, Z)모델에 적용하였다. 유도 결합 플라즈마장치의 RF 전력, 압력, 석영창 두께, 차폐부 높이에 따른 전자온도, 전자 밀도, 등가 정항 등가 인덕턴스 효율 결합계수 K, Q-factor의 변화를 구하였다. 특히 등가정항은 진공챔 버, 차폐부 및 코일의 손실저항을 고려하여 구하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.959-960
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• 2011

본 논문에서는 영구자석 오버행 구조를 가진 소형 BLDC 팬 모터의 효율 향상을 위한 연구를 하였다. 2차원 해석시 오버행에 따른 유효자속량을 고려한 오버행 계수를 산정하여 3차원 해석모델을 2차원 등가화가 가능하게 하여 실험하였다. 그리고 기존의 BLDC 팬 모터에 돌극형 회전자 철심을 삽입하여 영구자석 토크에 릴럭턴스 토크를 추가로 활용함으로써 효율을 향상시키는 연구를 하였다.

• Journal of the Korean Society for Railway
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• v.13 no.2
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• pp.139-146
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• 2010

In this study, a new equivalent modeling technique of rollingstock for 1-D collision dynamics was proposed using crash analysis of 3-D finite element model in some detail. To obtain good simulation results of 1-D dynamic model, the force-deformation curves of crushable structures should be well modelled with crash analysis of 3-D finite element model. Up to now, the force-deformation curves of the crushable structures have been extracted from crash analyses of sectionally partitioned parts of the carbody, and integrated into 1-D dynamic model. However, the results of the 1-D model were not satisfactory in terms of crash accelerations. To improve this problem, the force-deformation curves of the crushable structures were extracted from collision analysis of a simplified train consist in this study. A comparative study applying the suggested technique shows in good agreements in simulation results between two models for KHST.