• Structural Engineering and Mechanics
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• 제10권6호
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• pp.577-587
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• 2000

A 3D nonlinear finite element computation model is presented in order to analyze the concrete filled rectangular tubular (CFRT) composite structures. The concrete material model is based on a hypo-elastic orthotropic approach while the elasto-plastic hardening model is employed for steel element. The comparisons between experimental and analytical results show that the proposed model is a relatively simple and effective one. The analytical results show that the capacity of inner concrete of CFRT column mainly depends on the two diagonal zones, and the confining effect of CFRT section is mainly concentrated on the corner zones. At the ultimate state, the side concrete along the section cracks seriously, and the corner concrete softens with the increase of compressive strains until failure.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2006년도 추계 학술발표회
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• pp.291-311
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• 2006

The acceleration of consolidation by stone columns was mostly analysed within the framework of a basic unit cell model (i.e. a cylindrical soil body around a column). A method of converting the axisymmetric unit cell into the equivalent plane-strain model would be required for two-dimensional numerical modelling of multi-column field applications. This paper proposes two practical simplified conversion methods to obtain the equivalent plane-strain model of the unit cell, and investigates their applicability to multi-column reinforced ground. In the first conversion method, the soil permeability is matched according to an analytical equation, whereas in the second method, the column width is matched based on the equivalence of column area. The validity of these methods is tested by comparison with the numerical results of unit-cell simulations and with the field data from an embankment case history. The results show that for the case of linear-elastic material modelling, both methods produce reasonably accurate long-term consolidation settlements, whereas for the case of elasto-plastic material modelling, the second method is preferable as the first one gives erroneously lower long-term settlements, where plastic yielding of stone column are ignored.

• 대한조선학회논문집
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• 제44권1호
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• pp.32-39
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• 2007

A three-dimensional finite element model has been developed to simulate the MIG P/S welding process of two aluminum plates. The finite element calculations are performed using ANSYS finite element code, which takes into account the thermal and mechanical non-linear material properties. The results of finite element analysis compared with those of experiment to show its validity in view of distortions. Parametric studies are carried out on the validated model to assess the effects of various factors on the final residual distortion. Large deformations, temperature dependent material properties are included in the model. Finally, the formulas of fitting curves of angular distortion transverse shrinkage, and longitudinal shrinkage have been proposed.

• 산업기술연구
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• 제22권B호
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• pp.211-218
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• 2002

The paper is to show the behavior of composit ground which is installed with sheet pile in soft soil improved by sand compaction pile. The results of load-settlement relationship, earth pressure, stress concentration characteristics, and final water content were obtained by centrifuge model test. Two cases of tests, installation of sheet pile on the corner and both side of the loading plate for the improved SCP ground which was designed twice of the footing width, were performed for the tests under the vertical and horizontal loading and both side of corner. Finite element program(CRISP) for sand compaction pile using elasto-plastic model and numerical analysis for soft soil using modified cam-clay constitutive equation were compared and analized with the results of model tests. The result of analysis show the increased bearing capacity of soil after, SCP and sheet pile was installed.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1999년도 봄 학술발표회 논문집
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• pp.295-302
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• 1999

This paper is the experimental and analytic of reinforced concrete hemisphere dome under vertical load. It is described that when the reinforced concrete hemispherical dome supported on cylindrical wall is loaded vertically, how the opening part of dome will behave mechanically The experimental and analytic model is a Hemispherical dome with opening and the meridian angle of opening is 76$^{\circ}$at the center of sphere under concentrated load around the opening, but this is reinforced by a ring is sufficient stiffness. The diagrams of crack development are represented to understand the behavior of the reinforced concrete hemispherical dome. The method of crack analysis will be applied the rigid element spring model. The rigid element spring model is a new discrete element analysis, each divided element is assumed by rigid elements without deformation which is interconnected with elasto-plastic spring system.

• 한국지진공학회:학술대회논문집
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• 한국지진공학회 1998년도 춘계 학술발표회 논문집 Proceedings of EESK Conference-Spring 1998
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• pp.180-187
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• 1998

In this paper the attention is focused on the modeling of reinforced concrete(R/C) wall structures to check effectiveness and reliability of elasto-plastic analysis. A relatively simple and reliable wall model is investigated, which is suitable to be efficiently incorporated in a practical pushover analysis of R/C wall structural systems. Two types of analogous frames have been examined to the stress analysis of shear walls. One analogous frame is similar to the widely used wide-column model, the second analogous frame also is called truss model which includes vertical edge column and braces. Further studies are needed to apply to nonlinear seismic analysis of building structure with R/C shear walls.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2006년도 추계학술대회 논문집
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• pp.1348-1353
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• 2006

In this paper, nonlinear elasto-plastic analysis was performed to investigate the stability of the rapid embankment under undrained condition. The commercial code ABAQUS/Standard was used in the study. Resonant Column test (RC test) results and Ramberg-Osgood model were utilized to simulate the nonlinear behavior of soft clay. Ramgerg-Osgood model was tested whether it simulates the nonlinear behavior of the soil properly in first. Then the analysis result was compared with the previous research results. It was found that the Ramberg-Osgood model matched well with the soil behavior of soft clay in the rapid embankment under undrained condition.

• 터널과지하공간
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• 제20권2호
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• pp.73-81
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• 2010

본 논문에서는 여러 가지의 구성방정식 모델을 이용하여 NATM 터널의 유한요소 해석의 적용에 대하여 설명하였다. 일련의 2차원 평면변형률 조건하 NATM 터널의 지반-구조물에 대한 해석을 분석하였다. 사용한 4가지 구성방정식 모델로는 선형탄성, Mohr-Coulomb 탄소성, 변형경화, 연화지반모델이다. 터널설계에서는 지표면의 침하, 지보재 축력에 대한 적절한 예측이 필요하다. 수치해석결과 진보된 구성방정식 모델이 지반변형과 지보재의 축력에 대해 보다 적절한 결과를 나타내었다.

• Computers and Concrete
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• 제17권6호
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• pp.703-721
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• 2016

A novel approach to modeling concrete behavior at the stage of its maturing is presented in this paper. This approach assumes that at any point in the structure, concrete is composed of a set of layers that are activated in time layer by layer, based on amount of released heat that is produced during process of the concrete's maturing. This allows one to assume that each newly created layer has nominal stiffness moduli and tensile/compressive strengths. Hence introduction of explicit stiffness moduli and tensile/compressive strength dependencies on time, or equivalent time state parameter, is not needed. Analysis of plain concrete (PC) and reinforced concrete (RC) structures, especially massive ones, subjected to any kind of straining in their early stage of existence, mostly due to external loads but especially by thermal loading and shrinkage, is the goal of the approach. In this article a simple elasto-plastic softening model with creep is used for each layer and a general layered model behavior is illustrated on one-dimensional (1D) examples.

• 한국강구조학회 논문집
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• 제22권6호
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• pp.553-561
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• 2010

본 논문은 점성 감쇠기를 가진 셀프 센터링 단자유도 시스템과 탄소성 거동을 하는 단자유도 시스템의 내진 성능을 해석적 연구를 통하여 두 시스템이 유사한 최대 변위 응답을 갖도록 하는 점성 감쇠기의 감쇠비를 근사적으로 구하는 것을 목적으로 한다. 우선, 점성 감쇠기를 가진 셀프 센터링 단자유도 시스템의 조화 반복 가력 시의 거동에 대하여 설명하고 거동을 구현할 수 있는 해석모델을 소개한 후 두개의 단자유도 시스템의 이력거동을 특징지을 수 있는 해석변수를 설정하고 20개의 역사지진을 사용하여 비선형 시간 이력 해석을 실시하였다. 대부분의 경우 약 10 ~ 15% 정도의 점성 감쇠비를 가진 셀프 센터링 단자유도 시스템이 탄소성 거동을 하는 단자유도 시스템과 유사한 평균 최대 변위 응답을 보였다. 아울러, 3개의 탄소성 거동을 하는 단자유도 시스템과 6개의 점성 감쇠기를 가진 셀프 센터링을 선택하여 두 시스템의 내진성능을 보다 자세히 조사한 결과, 점성 감쇠기를 가진 셀프 센터링 시스템이 진동이 끝난 후 잔류변형이 남지 않았을 뿐만 아니라 약 15%의 감쇠비를 가진 점성 감쇠기를 가진 셀프 센터링 시스템은 탄소성 거동의 단자유도 시스템보다 우수한 최대 변위와 가속도 응답을 보였다.