• 한국철도학회논문집
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• 제9권2호
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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.

• 한국지반환경공학회 논문집
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• 제20권10호
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• pp.5-14
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• 2019

최근 우리나라에서도 지진이 발생하여 대도시의 초고층 건물의 내진안정성에 대한 관심이 높아져 이에 대한 연구가 증가하고 있다. 또한 대부분의 내진설계 및 해석은 지반을 간접적으로 고려하고 있고, 3D 동적해석을 이용한 내진해석 연구는 미비한 실정이다. 따라서 본 연구에서는 지반을 포함한 SSI 연속체 모델에 기초한 2D 및 3D 동적해석을 수행하고 거동을 비교 분석하였다. 동적해석을 위해 지반범용해석 프로그램인 MIDAS GTS NX를 이용하여 선형시간이력해석을 수행하였다. 이를 위해 초고층 건물이 기반암 위에 시공되고 표층에 묻혀있는 것으로 가정하고, 선정된 파라미터를 기준으로 민감도 분석을 수행하였다. 동적거동은 수평변위, 층간변위비, 휨응력, 취약부를 이용하여 비교 분석하였다. 대부분의 경우, 2D 동적거동은 3D보다 크게 산출하여 더 보수적인 결과를 보였으며, 취약부의 수와 크기는 증가하는 것으로 나타났다.

• Geomechanics and Engineering
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• 제17권4호
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• pp.317-322
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• 2019

This paper presents the results of parametric analyses to compute the axial capacity of a suction pile using 2D and 3D finite element approaches. The study is intended to simplify the process of analyzing suction piles from 3D to 2D model. The research focuses on obtaining the coefficient to be applied into the 2D model in order to obtain results that are as close as possible to the 3D model. Two 2D models were used in the analysis, namely the plane strain and axisymmetric models. The analyses were performed using two actual offshore soil data of the North and West Java Indonesia. The study reveals that the simplification of model through 2D Finite Element is achievable by applying the appropriate coefficient to the stiffness parameters. The results show that the simplified model of the 2D FEA provides more conservative results (with the difference between 2% to 7%) than the 3D FEA.

• 대한공간정보학회지
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• 제16권4호
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• pp.41-48
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• 2008

현재 활용되는 대부분의 3차원 모델은 3차원 객체의 가시화에 중점을 두고 있고 토폴로지 구조를 가지고 있지 않아 3차원 공간분석 및 응용에 있어 한계가 존재한다. 그리고 실내 공간의 수많은 객체들간의 관계를 완전 토폴로지 기반으로 구현하는 것은 복잡도나 연산속도가 지나치게 증가하여 현실성이 떨어진다. 이와 같은 문제를 해결하기 위해 본 연구에서는 공간 DBMS를 이용하여 실내 3차원 공간을 보다 간단하게 구축하는 방안을 제시하였다. 건물 내 각 공간의 공간정보와 속성 정보를 테이블 단위로 저장하면 DBMS의 빠른 질의와 연산 및 분석이 가능하다. 또한 질의를 통해 추출한 공간 데이터를 이용하여 2차원 및 3차원으로 가시화할 수도 있다. 본 연구에서는 층별 CAD 데이터를 공간 DBMS로 저장하여 2차원상의 토폴로지를 구현하고, 이를 3차원으로 가시화 할 수 있는, 2D-3D Hybrid 데이터모델을 제시하였다. 이러한 모델을 공간 DBMS로 구축하고 공간 함수와 질의를 활용하여 2차원 및 3차원으로 가시화 하는 과정을 제시하였고, 이를 이용하는 사례로서 실내 대피 경로 안내 시스템을 구축하는 과정을 예시하였다.

• 한국지진공학회논문집
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• 제21권1호
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• pp.69-76
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• 2017

Seismic analyses of a pile under a large rigid basement foundation embedded in the homogeneous soil layer were performed practically by a response displacement method assuming a sinusoidal wave form. However, it is hard to take into account the characteristics of a large mat foundation and a heterogeneous soil layer with the response displacement method. The response displacement method is relevant to the 2D problems for longitudinal structures such as tunnel, underground cave structure, etc., but might not be relevant with isolated foundations for building structures. In this study, seismic pile analysis by a pseudo 3D finite element method was carried out to compare numerical results with results of the response displacement method considering 3D characteristics of a foundation-soil system which is important for the building foundation analyses. Study results show that seismic analyses results of a response displacement method are similar to those of a pseudo 3D numerical method for stiff and dense soil layers, but they are too conservative for a soft soil layer inducing large soil pressures on the foundation wall and large pile displacements due to ignored foundation rigidity and resistance.

• 한국도로학회논문집
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• 제18권1호
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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.

• Advances in aircraft and spacecraft science
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• 제2권3호
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• pp.275-302
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• 2015

Theoretical and numerical assessments of approximate evaluations and simplified analyses of piezoelectric structures transverse shear modal effective electromechanical coupling coefficient (EMCC) are presented. Therefore, the latter is first introduced theoretically and its approximate evaluations are reviewed; then, three-dimensional (3D) and simplified two-dimensional (2D) plane-strain (PStrain) and plane-stress (PStress) piezoelectric constitutive behaviors of electroded shear piezoceramic patches are derived and corresponding expected short-circuit (SC) and open-circuit (OC) frequencies and resulting EMCC are discussed; next, using a piezoceramic shear sandwich beam cantilever typical benchmark, a 3D finite element (FE) assessment of different evaluation techniques of the shear modal effective EMCC is conducted, including the equipotential (EP) constraints effect; finally, 2D PStrain and PStress FE modal analyses under SC and OC electric conditions, are conducted and corresponding results (SC/OC frequencies and resulting effective EMCC) are compared to 3D ones. It is found that: (i) physical EP constraints reduce drastically the shear modal effective EMCC; (ii) PStress and PStrain results depend strongly on the filling foam stiffness, rendering inadequate the use of popular equivalent single layer models for the transverse shear-mode sandwich configuration; (iii) in contrary to results of piezoelectric shunted damping and energy harvesting popular single-degree-of-freedom-based models, transverse shear modal effective EMCC values are very small in particular for the first mode which is the common target of these applications.

• 한국전산구조공학회논문집
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• 제29권5호
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• pp.471-482
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• 2016

이 연구에서는 p-version 동적무한요소법을 도입함으로써 FE-IE 기법에 기반한 KIESSI-3D 프로그램의 속도향상에 역점을 두었다. KIESSI-3D의 성능을 평가하기 위해 8가지 실규모 SSI 문제에 대한 수치해석을 수행하였다. 이를 위해 근역지반 모델의 반경($r_0$)이 구조물기초 반경(R)의 1.2배, 1.5배, 3.0배인 KIESSI-3D 해석모델을 고려하였다. 또한 SASSI2010 프로그램을 이용한 SSI 해석을 수행하였으며, 이 결과를 KIESI-3D에 의한 결과와 정확성 및 계산속도를 비교하였다. 수치해석 결과, 인 KIESI-3D 모델을 사용하면 정확한 해석을 수행할 수 있음을 알 수 있었다. 계산속도 측면을 보면, 새로운 KIESSI-3D의 해석속도는 기존 KIESSI-3D에 비해 최대 25배 빠른 것으로 나타났다.

• Archives of Pharmacal Research
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• 제22권4호
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• pp.423-427
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• 1999

A study was carried out to evaluate flavonol glycosides in leaves of Symplocarpus renifolius (Araceae). From the water fraction of the MeOH extract, three new flavonol glycosides were isolated along with three known compounds, Kaempferol-3-O-$\beta$-glucopyranosyl-($1{\rightarrow}2$)-$\beta$-D-glucopyranosyl-7-O-$\beta$-D-glucopyranoside, quercetin-3-O-$\beta$-D-glucopyranosy-1-($1{\rightarrow}2$)-$\beta$-D-glucopyranoside, and caffeic acid. The structures of the new flavonol glycosides were elucidated by chemical and spectral analyses a quercetin-3-O-$\beta$-D-glucopyranosyl-($1{\rightarrow}2$)-$\beta$-D-glucopyranosyl-7-O-$\beta$-D-glucopyranoside, isorhamnetin-3-O-$\beta$-D-glucopyranosyl-(1 2)-$\beta$-D-glucopyranosyl-7-O-$\beta$-D-glucopyranosdie, and quercetin-3-O$\beta$-D-glucopyranosyl-($1{\rightarrow}2$)-$\beta$-D-glycopyranosyl-7-O-($6^{IIII}$-trans-caffeoyl)-$\beta$-D-glucopyranoside.

• 지질공학
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• 제17권3호
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• pp.381-391
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• 2007

본 연구에서는 2차원 유한요소법과 3차원 한계평형법을 함께 이용하여 테일러스 분포사면의 안정성을 해석하였다. Phase2를 이용한 유한요소해석에서는 발생응력의 분포를 이용하여 파괴심도를 추정하였다. 파괴면은 테일러스층 하부에 약 3-10m의 두께로 분포하는 붕적층 내에서 발생하였다. 유한요소해석 결과와 지질조사결과를 바탕으로 3차원 모델을 작성하여 한계평형해석을 실시하였다. 3차원 한계평형해석결과를 보면 건조시에는 모든 사면에서 안정한 것으로 나타났으나, 집중호우에 의해 지하수면이 붕적층을 포화시킬 때에는 급격히 불안정해지는 것으로 나타났다.