• Title, Summary, Keyword: 초기형상해석

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A Structural Analysis Model for the Initial Configuration of a Suspension Bridge Considering the Erection Method of Stiffening Girders (보강형의 시공방법을 고려한 타정식 현수교의 초기형상해석 모델)

  • Ko, Seong Seok;Kang, Sung Hoo;Park, Sun Joon;Jung, Jae Ho
    • Journal of The Korean Society of Civil Engineers
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    • v.29 no.4A
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    • pp.337-346
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    • 2009
  • To determine the initial configuration of the suspension bridge appropriate idealization model and analysis procedure are proposed as considering the boundary and loading conditions of stiffening girder during the erection. The construction stages of a suspension bridge are divided into two steps which are the first stage of the erection and the second stage of the completion in terms of the erection time of stiffening girders, and depending upon such an erection step the initial configuration analysis is classified the first configuration analysis and the revision analysis of the second configuration. The boundary and loading conditions and the analysis procedures for each stage are suggested and the results are verified by comparing with existing data. The results show that the proposed method provides better solution compared to the results using existing method.

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Initial Shape Analysis of 3 Dimensional Suspension Bridges using Improved TCUD Methods (개선된 TCUD법을 이용한 3차원 현수교의 초기형상해석)

  • Jo, Kyeong-Sik;Kim, Min;Kim, Moon-Young
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.78-81
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    • 2011
  • 본 논문에서는 개선된 TCUD(Improved TCUD, I.TCUD)법 및 개선된 초기부재력법(Improved Initial Force Methods, I.IFM)을 이용하여 3차원 현수교의 초기형상해석을 수행하였다. 절점평형법에 의하여 초기 평형상태를 결정하고, 이때 계산된 무응력장을 초기값으로 입력하여 비선형 해석을 수행하여 나온 값을 초기값으로 하여 해석을 반복한다. 이를 통하여 간단한 수치 해석 기법인 I.IFM이 정밀한 I.TCUD법과 비교하여 근접한 결과를 나타내는 것을 수치예제를 통하여 확인하였다.

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Comparison Study of An Improved Initial Force and TCUD Method for Initial Shape Analysis of Cable-Stayed Bridges (사장교의 초기형상해석을 위한 개선된 초기부재력법 및 TCUD법의 비교연구)

  • Kim, Dong-Yeong;Jo, Kyeong-Sik;Kim, Moon-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.25 no.1
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    • pp.101-108
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    • 2012
  • Initial shape analysis for cable-stayed bridges should be able to find optimizated initial cable forces and unstrained length that minimize deflection and bending moments of the deck and pylon. Comparison study of an improved initial force method and TCUD method for determination of initial cable forces in cable-stayed bridges is presented in this paper. For this purpose, an elastic catenary cable element and a nonlinear frame element are firstly described. And concepts and algorithm of two analysis methods are then presented. Finally to demonstrate the validity and the accuracy of two methods, numerical examples for initial state problems of cable-stayed bridges are given and compared based on these methods.

A Simplified Analysis Method for Determining an Optimized Initial Shape of Cable-Stayed Bridges (사장교의 최적 초기형상 및 무응력길이 결정을 위한 간략해석법)

  • Jung, Myung Rag;Park, Se Woong;Min, Dong Ju;Kim, Moon Young
    • Journal of The Korean Society of Civil Engineers
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    • v.36 no.6
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    • pp.947-954
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    • 2016
  • A simplified analysis method is first proposed in order to determine an optimized initial shape of cable-stayed bridges including all unstrained element lengths without using complicated nonlinear FE analysis. The unstrained-length based FE method is then presented using the unstrained lengths by the simplified analysis. To demonstrate validity and accuracy of the proposed method, Incheon bridge model having the fabrication camber is constructed and initial shaping analysis is performed using the presented method and commercial finite element analysis program, MIDAS. Resultantly it is shown that the initial solutions by the proposed algorithm are well optimized and in good agreement with those by MIDAS except for axial displacements of the main member.

막과 케이블 구조물의 형상탐색해석

  • 서삼열;권택진
    • Computational Structural Engineering
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    • v.5 no.3
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    • pp.19-28
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    • 1992
  • 이 글에서는 막 구조물의 설계에서 자주 제기되는 형상결정 문제에 대한 접근방법을 제시하고자 하였다. 형상결정 문제는 막 구조물이 휨 강성이 전혀 없거나, 빈약한 재료를 사용하는데 기인하여 제기되고, 막 구조물의 설계에서 불안정영역의 발생을 피하기 위해서는 형상의 기준면에서 곡률과 비틀림의 변화를 최소화해야 하며 이러한 변화를 최소화하기 위해서는 형상이 적용하중의 막력에 의한 평형면에 근접하는 것이 바람직하다. 또한, 초기에 막 구조물에 도입된 초기장력에 오차가 발새하면 막면은 스스로 등장력의 형태로 이동하게 되므로, 초기에 막장력의 분포가 등장력의 상태가 되도록 그 형상을 결정하는 것이 바람직하다. 따라서, 이러한 조건을 만족하는 형상탐색문제는 이러한 종류의 구조물의 설계에서는 매우 중요한 문제가 된다. 그러나 국내에서는 막과 케이블 구조물의 형상해석과 응력-변형해석에 범용적으로 사용될 수 있는 프로그램의 개발이 미약하고 이러한 구조방식에 대한 국내의 인식에 크게 부족한 실정이다. 따라서 이 글이 막과 케이블 구조물의 설계에서 형상탐색해석이 반드시 필요한 이 구조물의 구조적 특성을 이해하는데 조금이라도 도움이 될 수 있기를 기대한다.

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A Study on the Shape-Decision Technique of Membrane Structures According to the Design Process and Shape Analysis (건축 설계프로세스와 형상해석을 통한 막 구조물의 형상결정 방안에 관한 연구)

  • Park, Sun-Woo;Kim, Seung-Deog;Shon, Su-Deok;Jeong, Eul-Seok
    • Journal of the Korean Association for Spatial Structures
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    • v.7 no.2
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    • pp.115-124
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    • 2007
  • The initial shape is arrived at by a self-formation process, which accomplishes a form in the natural world, or is determined analytically by considering the equilibrium of initial stress only. Therefore, the self-formation process, which accomplishes a form in the natural world is grasped and the types of modeling techniques available to find the shapes of soft structures are well investigated and classified. To establish a form-finding modeling techniques, the models of string, soap film, fabric, rubber, plaster, and etc. are used. These modeling techniques can be used as a method of understanding the characteristics of structures when the material of model shows similar characteristics. Generally, the model test confirms the structure based on numerical analysis, at the same time it is important preceding process to develop such a program. With the above process, the relationship between model test and numerical analysis becomes a feedback process. Therefore, in this study, two examples which have been accomplished from such a technique are investigated and considered according to modeling process.

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Initial Shape Analysis of Suspension Bridge System under Dead Load (고정하중을 받는 현수교 시스템의 초기형상 결정법)

  • Kim, Min;Kim, Moon-Young
    • Journal of Korean Society of Steel Construction
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    • v.22 no.6
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    • pp.511-521
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    • 2010
  • This paper presents a simplified analysis method of determining the initial shape of suspension bridges, including the horizontal tension force of the main cable and the locations of each hanging point, considering the force equilibrium condition of each hanging point. This method is effective because it requires less effort than the methods used in other studies, for which complicated non-linear analysis was used, to comparatively determine the exact initial shape. The accuracy and validity of the present method are demonstrated by comparing the results of this study with those of previous researchers' numerical examples, including 2D and 3D models.

Forward Projection Using Fuzzy Logic in Axisymmetric Finite Element Simulation for Cold Forging (축대칭 냉간단조의 유한요소해석에서 퍼지로직을 이용한 전방투사법)

  • 정낙면;이낙규;양동열
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.16 no.8
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    • pp.1468-1484
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    • 1992
  • In the present paper forward projection is proposed as a new approach to determine the preform shape in rib-web type forging. In the forward projection technique an optimal billet is determined by applying some mathematical relationship between geometrical trials in the initial billet shape and the final products. In forward projection a volume difference between the desired product shape and the final computed shape obtained by the rigid-plastic finite element method is used as a measure of incomplete filling of working material in the die. At first linear inter-/extrapolation is employed to find a proper trial shape for the initial billet and the method is successfully applied to some cases of different aspect ratios of the initial billet. However, when the initial guesses are not sufficiently near the optimal value linear inter-/extrapolation does not render complete die filling. For more general application, a fuzzy system is used in the forward projection technique in order to determine the initial billet shape for rib-web type forging. It has been thus shown that the fuzzy system is more reliable for the preform design in the rib-web type forging process.

Practical Determination Method of Initial Cable Forces in Cable-Stayed Bridges (사장교 시스템의 실용적인 초기형상 결정법)

  • Song, Yo-Han;Kim, Moon-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.24 no.1
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    • pp.87-95
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    • 2011
  • A rational method for determination of initial cable forces in cable-stayed bridges without complicated nonlinear analysis is presented. Initial shape analysis for cable-stayed bridges should be able to find optimizated initial cable forces and unstrained length that minimize deflection and vending moments of the deck and pylon. A presented method utilizing the idea of force equilibrium organizes initial shape analysis for each types of cable-stayed bridges. The results of that analysis were compared to several existing methods for 2D numerical examples. And for 3D actual bridges, the improved TCUD method was performed to demonstrate the accuracy of this study.

An Elastic Parabolic Cable Element for Initial Shaping Analysis of Cable-Stayed Bridges (사장교의 초기형상해석을 위한 탄성포물선 케이블요소)

  • Kyung, Yong-Soo;Kim, Moon-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.20 no.1
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    • pp.1-7
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    • 2007
  • This study introduces an elastic parabolic cable element for initial shaping analysis of cable-stayed bridges. First, an elastic catenary cable theory is shortly summarized by deriving the compatibility condition and the tangent stiffness matrices of the elastic catenary cable element. Next, the force-deformation relations and the tangent stiffness matrices of the elastic parabolic cable elements are derived from the assumption that sag configuration under self-weights is small. In addition the equivalent cable tension is defined in the chord-wise direction. Finally, to confirm the accuracy of this element, initial shaping analysis of cable-stayed bridges under dead loads is executed using TCUD in which stay cables are modeled by an elastic parabolic cable and an elastic catenary cable element, respectively. Resultantly it turns that unstrained lengths of stay cables, the equivalent cable tensions, and maximum tensions by the parabolic cable element are nearly the same as those by the catenary cable elements.