• Title, Summary, Keyword: 비선형 거동

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Ultimate Analysis of Prestressed Concrete Cable-Stayed Bridges (프리스트레스트 콘크리트 사장교의 극한해석)

  • Lee, Jae Seok;Kang, Young Jin
    • Journal of The Korean Society of Civil Engineers
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    • v.13 no.5
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    • pp.85-98
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    • 1993
  • A method of analysis for the material and geometric nonlinear analysis of planar prestressed concrete cable-stayed bridges including the time-dependent effects due to load history, creep, shrinkage, aging of concrete and relaxation of prestress is described. The analysis procedure, based on the finite element method, is capable of predicting the response of these structures through elastic, cracking, inelastic and ultimate ranges. The nonlinear formulation for the description of motion is based on the updated Lagrangian approach. To account for the material nonlinearity, nonlinear stress-strain relationship and cracking of concrete, nonlinear stress-strain relationships of reinforcing steel, prestressing steel, and cable, including load reversal are given. Results from a numerical examples on ultimate analyses of cable-stayed bridges are presented to illustrate the analysis method.

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Development of Analytical Method of Piled-Raft Foundation Considering Nonlinear Behavior of Pile (말뚝의 비선형거동이 고려된 전면지지 말뚝기초 해석기법의 개발)

  • Park, Hyun-Il
    • Journal of the Korean Geotechnical Society
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    • v.24 no.10
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    • pp.17-24
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    • 2008
  • In this study, two-dimensional finite element method has been developed to simply consider the nonlinear load-settlement behavior of piled raft foundation subjected to vertical loads. The raft is modeled as the plate finite element based on Mindline's theory and the pile is modeled as the proposed simple pile model that is easy to consider the complex nonlinear load-settlement behavior between pile and soil. The developed numerical method has been compared with the settlement data of lab-scaled experiment and numerical solutions to verify that the developed numerical method shows satisfactory prediction for the nonlinear load-settlement of piled raft foundation.

Numerical Analysis of Rock Behavior with Crack Model Implementation (균열모형을 이용한 암석거동의 수치해석)

  • 전석원
    • Proceedings of the Korean Society for Rock Mechanics Conference
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    • pp.25-31
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    • 1999
  • 암석 내에 포함된 불연속면으로 인하여 암석은 압축하중 하에서 복잡한 거동을 한다. 이러한 복잡한 거동은 변형률강화(strain hardening), 변형률연화(strain softening), 부피팽창(dilatancy)등의 비선형 거동을 포함하는데, 이들은 균열의 성장, 상호작용(interaction), 연합(coalescence) 등을 통하여 발생한다(Brace et al., 1972; Kranz, 1983). 이와 같은 암석의 비선형적 거동을 설명하기 위하여 여러 형태의 균열모형이 개발된 바 있다(Costin, 1985; Nemat-Nasser & Horii, 1982; Wang & Kemeny, 1993; Jeon, 1998). (중략)

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Analysis of Elasto-Plastic Problems Using the Generalized Finite Element Method with Global-Local Enrichment Functions (전체-국부 확장함수를 지닌 일반유한요소법을 이용한 탄소성해석)

  • Han, So-Jeong;Kim, Hee-Cheul;Lee, Young-Hak;Kim, Dae-Jin
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.773-777
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    • 2011
  • 본 논문에서는 국부적으로 비선형 거동을 보이는 고전적인 $J_2$ 소성흐름 이론에 근거한 탄소성 문제의 해를 효율적으로 구하기 위해 전체-국부 확장함수를 지닌 일반유한요소법을 제안한다. 제안된 기법은 비선형 거동을 보이는 영역을 포함하는 국부 문제의 비선형 해를 구하고 이를 일반유한요소법의 단위 오목 분할의 개념을 통해 전체 문제의 해 공간을 확장하는데 이용한다. 이는 적은 계산량으로 복잡한 탄소성문제의 정확한 해를 얻는 것을 가능하게 하며 기법의 강건성과 정확성을 입증하기 위한 수치해석 예제가 다루어진다.

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대공간 구조물의 비선형 해석기법

  • 김승덕
    • Computational Structural Engineering
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    • v.10 no.1
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    • pp.7-18
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    • 1997
  • 본 고에서는 컴퓨터를 이용하여 비선형문제를 어떻게 다룰 것인가에 관해 기초 지식에서부터 응용까지를 간단히 설명한다. 먼저 기하학적 비선형 문제를 중심으로, 기존의 비선형 해석기법에 관해 기초적인 기법부터 고난도의 기법까지 일반적으로 많이 사용되는 것을 자세히 소개한다. 또 대공간 구조물의 비선형 해석기법에 관한 이해를 돕기 위해 비교적 간단한 부재인 케이블/트러스 요소를 이용한 몇몇 예제와 비선형해석으로 인한 구조물 거동의 특성도 다룬다.

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Rheological Characterization of Aqueous Poly(Ethylene Oxide) Solutions : Stress Relaxation in Single-Step Large Shear Deformations

  • 송기원;예상호;장갑식
    • Proceedings of the Korean Fiber Society Conference
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    • pp.148-151
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    • 1998
  • 대부분의 고분자 가공공정에 있어서 가공원액(고분자 액체 또는 용융물)은 선형영역을 벗어나는 큰 크기의 변형을 받으므로 기존의 선형 점탄성 이론으로는 그 공정해석이 불가능하다. 그러므로 대변형하에서 고분자 물질의 비선형 거동 해석은 실제 공정과 관련된 공학적인 관점에서 볼 때 매우 중요한 과제라고 할 수 있다. 특히 응력완화 실험은 점탄성 액체의 비선형 완화 거동을 고찰하고 지금까지 제시된 각종 구성방정식을 평가하는데 유용하다.(중략)

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Probabilistic Nonlinear Analysis of Semi-Rigid Frames Considering Random Elastic Modulus (탄성계수 불확실성을 고려한 반강접 프레임 구조의 확률적 비선형 거동 해석)

  • Kim, Dae Young;Noh, Hyuk Chun
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.26 no.3
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    • pp.191-198
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    • 2013
  • In this paper, the effects of uncertain material constant on the nonlinear behavior of steel frames with semi-rigid joints are examined. As to the probabilistic model, a normal distribution is assumed to simulate the uncertain elastic modulus of steel material. A nonlinear structural analysis program, which can consider both semi-rigidity in joints of the steel frames and uncertainty in the material constant, is developed. Including the geometric, material and connection nonlinearites which are the parameters of nonlinear behavior of steel frames, probabilistic analysis is conducted based on the Monte-Carlo simulation. In the probabilistic analyses, we consider the three different cases for random variables. The deterministic analysis results are shown to be in good agreement with those of the previous research results in the literature. As to the probabilistic analyses, it is observed that the coefficient of variation(COV) of displacements increases as the loading increases, and that the values of COV are dependent on the structural features of the frames.

Analytical Study of Ultimate Behavior of Steel Cable-stayed Bridges (완성계 강사장교의 극한 거동의 해석적 연구)

  • Kim, Seungjun;Im, Seok-Been;Lee, Kee-Sei;Kang, Young-Jong
    • Journal of The Korean Society of Civil Engineers
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    • v.32 no.2A
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    • pp.85-95
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    • 2012
  • This paper presents an investigation on the ultimate behavior of steel cable-stayed bridges using nonlinear finite element analysis method. Cable-stayed bridges exhibit various geometric nonlinearities as well as material nonlinearities, so rational nonlinear finite element analysis should be performed for investigation of the ultimate behavior. In this study, ultimate behavior of steel cable-stayed bridges was studied using rational ultimate analysis method. Nonlinear equivalent truss element and nonlinear frame element were used for modeling the cable, girder and mast. Moreover, refined plastic hinge method was adopted for considering the material nonlinearity of steel members. In this study, the 2-step analysis method was used. Before live load analysis, initial shape analysis was performed in order to consider the dead load condition. For investigation of the ultimate behavior of steel cable-stayed bridges, analysis models which span length is 920.0 m were used. Radiating type and fan type were considered as the cable-arrangement types. With various quantitative evidences such as load-displacement curves, deformed shapes, locations of the yield point or region, bending moment distribution and so on, the ultimate behavior of steel cable-stayed bridges was investigated and described in this paper.

Nonlinear Analysis of Steel-concrete Composite Girder Using Interface Element (경계면 요소를 사용한 강·콘크리트 혼합 거더의 비선형 거동 해석)

  • Kwon, Hee-Jung;Kim, Moon Kyum;Cho, Kyung Hwan;Won, Jong Hwa
    • Journal of The Korean Society of Civil Engineers
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    • v.29 no.4A
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    • pp.281-290
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    • 2009
  • In this study, an analysis technique of hybrid girder considering nonlinearity of steel-concrete contact surface is presented. Steel-concrete hybrid girder shows partial-interaction behavior due to the deformation of shear connectors, slip and detachment at the interface, and cracks under the applied loads. Therefore, the partial-interaction approach becomes more reasonable. Contact surface is modeled by interface element and analyzed nonlinearly because of cost of time and effort to detailed model and analysis. Steel and Concrete are modeled considering non-linearity of materials. Material property of contact surface is obtained from push-out test and input to interface element. For the constitutive models, Drucker-Prager and smeared cracking model are used for concrete in compression and tension, respectively, and a von-Mises model is used for steel. This analysis technique is verified by comparing it with test results. Using verified analysis technique, various analyses are performed with different parameters such as nonlinear material property of interface element and prestress. The results are compared with linear analysis result and analysis result with the assumption of full-interaction.

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A Study on Seismic Behavior of Space Frame Bridge Using Three-Dimensional Nonlinear Dynamic Analysis (3차원 비선형 동적해석을 이용한 입체라멘교의 지진거동특성에 관한 연구)

  • 김익현
    • Journal of the Earthquake Engineering Society of Korea
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    • v.6 no.5
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    • pp.45-51
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    • 2002
  • The characteristics of nonlinear seismic behavior and failure mechanism of RC space frame in railroad viaducts have been studied by the numerical analysis in time domain. The structure concerned is modeled in 3 dimensional extent and the RC frame elements consisting of fibers are employed for the columns. The fibers are characterized as RC zone and PC one to distinguish the different energy release after cracking resulted from the bond characteristic between concrete and re-bar. Due to the deviation of the mass center and the stiffness center of the entire structure the complex behavior is shown under seismic actions. The excessive shear force is concentrated on the column beside flexible one relatively, which leads to the failure of bridge concerned.