• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.451-456
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• 2003

The behavior of concrete deep beams in shear is substantially influenced by beam size and shape, loading conditions, reinforcement details, and material properties. Therefore, it is not easy to predict the ultimate response of beams correctly and take into account all those factors in practical shear design. In this study, a grid softened strut-tie model approach for determining the shear strengths of various reinforced concrete deep beams is proposed. The validity of the approach is examined through the strength analysis of numerous reinforced concrete deep beams tested to failure. The approach can be further developed to improve the current deep beam design procedures by incorporating the actual shear resisting mechanisms of deep beams.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.245-252
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• 2001

The ultimate strength testing of a two-story, single-bay, and sway allowed space steel frame was performed. Considering a majority of large-scale frame tests in the past, only two-dimensional frames were experimentally studied. Therefore, three-dimensional experiment is needed to extend the knowledge of this field. The steel frame subjected to non-proportional vertical and horizontal load was tested. The load-displacement curve of the test frame is provided. The experiment results are useful for verification of the three-dimensional numerical analysis. The results obtained from 3D non-linear analysis using ABAQUS were compared with experimental data.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2002년도 가을 학술발표회 논문집
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• pp.557-564
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• 2002

One of the primary factors like plate structure In ship is redundancy structure that is comparable with ocean structure and frame structure. The more component material becomes buckling collapsed locally the less structure stiffness becomes accordingly. As a result, by increasing the load distribution of any other subsidiary structure continually component member collapses, therefore the structure could be in danger of collapse. So, in order to interpret this phenomenon precisely, the study on boundary condition of the ship's Plate and post-buckling analysis must be considered. In this study, the rectangular plate is compressed by the in-plane load. Buckling ＆ Ultimate strength characteristics we applied to be the elasto-plasticity large deformation by F.E.M. On this basis, elasto-plasticity of the plain plate are investigated. This study proved elasto-plasticity behaviour of tile ship's plate In accordance with boundary condition based on the series analysis In case of the compressive load operation.

• 한국전산구조공학회논문집
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• 제13권2호
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• pp.197-208
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• 2000

최 등/sup 1)/은 total lagrangian formulation에 근거한 증분 평형방정식을 적용하고, 강도행렬 산정시 회전각의 2차항을 포함시켜 기하학적 비선형 해석시 해의 수렴성을 향상시켰다. 또한 등매개 쉘 유한요소의 단점인 전단구속 현상과 제로 에너지 모드가 발생하는 문제를 극복하기 위하여 가정 변형률장을 적용하여 보강된 판 및 쉘 구조의 비선형 해석법을 개발하였다. 본 연구에서는 잔류응력을 고려한 쉘구조의 극한강도 해석을 수행하기 위하여, 대변형거동과 함께 소성붕괴거동을 추적할 수 있는 알고리즘을 제시한다. 잔류응력을 고려한 증분평형방정식에 return mapping algorithm을 이용한 탄소성 해석법을 결합시켜서 보강된 판 및 쉘구조의 극한거동을 파악한다. 수치해석 예제를 통하여 본 연구에서 제시된 유한요소 및 비선형 해석 알고리즘에 대한 효율성 및 적용성을 확인하였다.

• 한국지반공학회지:지반
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• 제5권3호
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• pp.19-28
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• 1989

본문은 전단과정에서 경화되는 모래와 같은 재료의 구성식을 연구하기 위하여 그 기초실험으로서 이미 경화된 콘크리트를 대상으로 3주응력을 독립적으로 제어할 수 있는 입방체삼축추축실험기를 통해 여러가지 응력경로 실험을 실시한 것이다. 실험으로서는 HC, CTC, TC, TE, SS 등 5종이고 그 들의 응력-변형률관계와 강도특성을 8면체면에서 고찰한 것이다. 이들을 통한 주요 결론은 다음과 같다. 1. 경화재료에 대한 전단강도의 크기는 CTC, TC, SS, TE의 순서이다. 2. 8면체전단강도는 응력경로에 의존하고 3. 또한 등방응력이 클수록 좋다. 4. 8면체면에서 극한포락선은 원추형상이다. 5. 마찰성재료인 경화재료에 대해서는 인장강도의 영향을 고려해야 한다.

• Structural Engineering and Mechanics
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• 제24권2호
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• pp.137-154
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• 2006

The reliable pushover analysis of RC structures requires a realistic prediction of moment-curvature relations, which can be obtained by utilizing proper constitutive models for the stress-strain relationships of laterally confined concrete members. Theoretical approach of Mander is still a single stress-strain model, which employs a multiaxial failure surface for the determination of the ultimate strength of confined concrete. Alternatively, this paper introduces a simple and practical failure criterion for confined concrete with emphasis on introduction of significant modifications into the two-parameter Drucker-Prager model. The new criterion is only applicable to triaxial compression stress state which is exactly the case in the RC columns. Unlike many existing multi-parameter criteria proposed for the concrete fracture, the model needs only the compressive strength of concrete as an independent parameter and also implies for the influence of the Lode angle on the material strength. Adopting Saenz equation for stress-strain plots, satisfactory agreement between the measured and predicted results for the available experimental test data of confined normal and high strength concrete specimens is obtained. Moreover, it is found that further work involving the confinement pressure is still encouraging since the confinement model of Mander overestimates the ultimate strength of some RC columns.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.359-362
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• 2003

Carbon fiber sheet is attractive due to its good tensile strength, resistance to corrosion, and low weight. The strengthening of concrete structures with externally bonded carbon fiber sheets is increasingly being used for repair and rehabilitation of existing structures. However CFS strengthened beams break down under the service loads. As rupture strain is not reached ultimate value, reduction of the tensile strength is recommended. This study evaluate CFS tensile strength reduction factor which is required to analyze bending moment.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 가을 학술발표회 논문집
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• pp.269-276
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• 2001

Tubular structures are widely used for offshore platforms and truss type structures. In this paper, nonlinear finite element analysis is used to assess the static strength of stiffened tubular T-joints subjected to compressive brace loading. This joints was modelled with and without internal ring stiffener According to variation of ring geometries, the effect of ring stiffener for T-joints are investigated. Internal ring stiffener is found to be efficient improving ultimate strength of tubular joints. Relations of ring thickness and axial strength are observed considering geometric parameters of ring stiffeners.

• 대한조선학회논문집
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• 제52권6호
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• pp.444-451
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• 2015

Lifting lugs are frequently used in shipyard to transport and turn over blocks of ship and offshore structures. As the shipbuilding technology develops, blocks has become bigger and bigger, and block management technology takes a more important role in shipbuilding to enhance the productivity. For the sake of economic as well as safe design of lug structure, more rational design procedure based on the rigorous structural analysis is needed. This study is concerned with the optimum design of T type lug which is frequently used in shipyard. The optimum thickness of lug's main body is to be determined based on the results of non-linear strength analysis. As far as the present results for the present T type lugs having different capacity are concerned, it seems to be necessary to review the current design procedure of lug structure. The present design procedure can be extensively used in design of various types of lug structures used in shipyard.

• Steel and Composite Structures
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• 제47권3호
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• pp.437-450
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• 2023

A half open cross section built-up column, namely cold-formed thin-walled steel built-up column with 12-limbsection (CTSBC-12) is put forward. To deeply reveal the mechanical behaviors of CTSBC-12 under axial compression and put forward its calculation formula of axial bearing capacity, based on the previous axial compression experimental research, the finite element analysis (FEA) is conducted on 9 CTSBC-12 specimens, and then the variable parameter analysis is carried out. The results show the FEA is in good agreement with the experimental research, the ultimate bearing capacity error is within 10%. When the slenderness ratio is more than 96.54, the ultimate bearing capacity of CTSBC-12 decreases rapidly, and the failure mode changes from local buckling to global buckling. With the local buckling failure mode unchanged, the ultimate bearing capacity decreases gradually as the ratio of web height to thickness increases. Three methods are used for calculating the ultimate bearing capacity, the direct strength method of AISI S100-2007 gives result of ultimate axial load which is closest to the test and FEA results. But for simplicity and practicality, a simplified axial bearing capacity formula is proposed, which has better calculation accuracy with the slenderness ratio changing from 30 to 100.