• Title, Summary, Keyword: 좌굴

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Elastic Interactive Shear Buckling Behavior of Trapezoidally Corrugated Steel Webs (제형파형강판 복부판의 탄성 연성전단좌굴 거동)

  • Yi, Jong Won;Gill, Heung Bae;Lee, Hak Eun
    • Journal of Korean Society of Steel Construction
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    • v.17 no.6
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    • pp.707-715
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    • 2005
  • Corrugated webs have been used for composite prestressed concrete box girder bridges. Innovative steel plate girders using corrugated webs have been proposed. It has been found that analytical and experimental researches conducted to determine the strength of trapezoidally corrugated webs can fail with respect to three different buckling modes: local, global, and interactive shear buckling. Shear buckling capacity equations based on classical and orthotropic plate buckling theories have been proposed,but these equations show some differences. In this paper, geometric parameters that influence interactive shear buckling behavior with interaction effects are identified via extensive bifurcation buckling analysis using the finite element meth.

Nonlinear Finite Element Analysis on Global and Distortional Buckling of Cold-Formed Steel Members (냉간성형강재의 전체좌굴 및 뒤틀림좌굴에 대한 비선형유한요소해석)

  • Kang, Hyun Koo;Rha, Chang Soon
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.2
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    • pp.79-86
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    • 2014
  • This paper presents modelling approaches for the global and distortional buckling of cold-formed built-up steel sections using the finite element software packages, ANSYS and ABAQUS. Thin thickness of the cold-formed steel causes nonlinear behaviour due to local and distortional buckling, thus careful consideration is required in modelling for numerical analysis. Implicit static modelling using ANSYS provides unstable numerical results as the load approaches the limit point but explicit dyamic modelling with ABAQUS is able to display the behaviour even in post-buckling range. Meanwhile, axial load capacities obtained from the numerical analysis show higher values than the experimental axial capacities, due to eccentricity during the test. Axial capacities of the cold-formed steel obtained through numerical analysis requires reduction factor, and this paper suggests 0.88 for the factor.

Inelastic Buckling Analysis of Frames with Semi-Rigid Joints (부분강절 뼈대구조의 비탄성 좌굴해석)

  • Min, Byoung Cheol
    • Journal of Korean Society of Steel Construction
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    • v.26 no.3
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    • pp.143-154
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    • 2014
  • An improved method for evaluating effective buckling length of semi-rigid frame with inelastic behavior is newly proposed. Also, generalized exact tangential stiffness matrix with rotationally semi-rigid connections is adopted in previous studies. Therefore, the system buckling load of structure with inelastic behaviors can be exactly obtained by only one element per one straight member for inelastic problems. And the linearized elastic stiffness matrix and the geometric stiffness matrix of semi-rigid frame are utilized by taking into account 4th terms of taylor series from the exact tangent stiffness matrix. On the other hands, two inelastic analysis programs(M1, M2) are newly formulated. Where, M1 based on exact tangent stiffness matrix is programmed by iterative determinant search method and M2 is using linear algorithm with elastic and geometric matrices. Finally, in order to verify this present theory, various numerical examples are introduced and the effective buckling length of semi-rigid frames with inelastic materials are investigated.

Buckling Analysis of Pultruded Members under Axial Compression (축방향 압축력을 받는 인발성형부재의 좌굴해석)

  • Lee, Seung Sik;Back, Sung Yong
    • Journal of Korean Society of Steel Construction
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    • v.18 no.5
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    • pp.615-624
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    • 2006
  • In the present paper, an extended composite beam theory that has no restriction on the lay-up and can account for Poisson effect which is significant for composite materials is proposed. Buckling equations for composite thin-walled members which are subjected to axial compression are derived based on the composite beam theory. In order to check the validity of the derived buckling equations, the results of experiments on the flexural-torsional buckling of vinylester/E-glass and polyester/E-glass pultruded T-section members and the flexural buckling of vinylester/E-glass pultruded H-section members are used as numerical examples. The comparison of the analytical results to the experimental and FE analysis results reveals that the proposed buckling equations predict the buckling loads of pultruded members conservatively by about 7%.

Buckling Loads of Column with Constant Surface Area (일정표면적 기둥의 좌굴하중)

  • Lee, Byoung Koo;Park, Kwang Kyou;Lee, Tae Eun
    • Journal of The Korean Society of Civil Engineers
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    • v.31 no.1A
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    • pp.1-7
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    • 2011
  • This paper deals with buckling loads of the column with the constant surface area. The shape function of variable column depth is chosen as the linear taper. The ordinary differential equation governing buckled shapes of the column is derived based on the dynamic equilibrium equation of such column subjected to an axial load. Three kinds of end constraint of hinged-hinged, hinged-clamped and clamped-clamped are considered in numerical examples. Effects of the column parameters on buckling loads are extensively discussed. Especially, section ratios of the strongest column are calculated, under which the maximum, i.e. strongest, buckling loads are achieved. Also the buckled shapes are obtained for searching the nodal points where the inner transverse supports are simply installed to increase the buckling loads.

Determination of Effective Buckling Length of Plane Frames using Elastic and Inelastic System Buckling Analysis (탄성 및 비탄성 좌굴 고유치해석을 이용한 강뼈대구조의 유효좌굴길이)

  • Song, Ju-Young;Kyung, Yong-Soo;Kim, Moon-Young
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.18 no.2
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    • pp.169-179
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    • 2005
  • An improved method for evaluating effective buckling lengths of beam-column members in plane frames is newly proposed based on system inelastic buckling analysis. To this end, the tangent stiffness matrix of be am-column elements is first calculated using stability functions and then the inelastic buckling analysis method is presented. The scheme for determining effective length of individual members is also addressed. Design examples and numerical results ?uc presented to show the validity of the proposed method.

Buckling of Power-Plant Containment Liner Plate Structure during Lifting (원전 격납철판 구조물의 양중시 좌굴 특성)

  • Yang, Seong-Yeong;Lee, Jong-Sup;Lee, Sang-Bong
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.336-339
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    • 2011
  • 본 논문에서는 유한요소 프로그램 (ANSYS)을 이용하여 돔격납철판 (dome containment liner plate)의 양중시 좌굴특성의 연구를 수행하였다. 원전 격납철판의 양중시, 양중 와이어(wire)의 구조적인 배치특성상 격납철판에 압축력이 유발되고, 이러한 압축력은 격납철판의 좌굴을 일으킬 수 있다. 다양한 양중인자 (lifting factors)를 고려한 격납철판 유한요소모델을 수립하고, 이러한 양중인자들의 좌굴특성에 미치는 영향을 고찰하였다. 양중 와이어의 체결위치의 높이가 낮을 수록 좌굴강도가 증가하며, 라이너 플레이트 두께에 비례하여 좌굴강도가 증가하였다.

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Buckling Analysis using Fictitious Axial Forces and Its Application to Cable-Stayed Bridges with HSB800 Steel (가상축력을 이용한 좌굴해석 및 HSB800 강재를 적용한 사장교에 대한 적용성 분석)

  • Choi, Dong Ho;Yoo, Hoon;Gwon, Sun Gil;Lim, Ji Hoon
    • Journal of Korean Society of Steel Construction
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    • v.29 no.1
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    • pp.13-24
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    • 2017
  • System buckling analysis is usually used to determine the critical buckling load in the buckling design of cable-stayed bridges. However, system buckling analysis may yield unexpectedly large effective lengths of the members subjected to a relatively small axial force. This paper proposes a new method to determine reasonable effective lengths of girder and tower members in steel cable-stayed bridges using fictitious axial forces. An improved inelastic buckling analysis with modified tangent modulus is also presented. The effective lengths of members in example bridges calculated using the proposed method are compared with those obtained using the conventional buckling analysis method. The proposed method provides much more resonable effective lengths of the members. When girder and tower members are built with HSB800 steel instead of conventional steel, the effective lengths of the members under a small axial force slightly decreases in the inelastic buckling analysis without fictitious axial forces, while the proposed method that considers fictitious axial forces provides almost no changes in such lengths.

An Investigation of the Shear Buckling Characteristics of Sinusoidal Corrugated Steel Plates (정현파형 주름강판의 전단좌굴특성 분석)

  • Shon, Su-Deok;Yoo, Mi-Na;Lee, Seung-Jae;Kang, Joo-Won
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.18 no.3
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    • pp.10-19
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    • 2014
  • Corrugated steel plates are made by fabricating thin steel plates to have trapezoidal or sinusoidal corrugation, and the corrugated plates are able to maintain high out-of-plane rigidity even when they are used instead of thick flat plates. Also, corrugated steel plates have almost no axial rigidity due to the accordion effect. Thus, if they are applied to the webs of plate girders, designing can be easily conducted so that the webs bear only shear stresses. However, unlike flat plates, the shear buckling of corrugated steel plates has very complex characteristics where buckling occurs due to the interaction of local and global buckling, besides local buckling and global buckling. For the investigation of the cause and characteristics of this interactive buckling, studies on sinusoidal corrugated steel plates are fewer than studies on trapezoidal corrugated steel plates. Therefore, in this study, the shear buckling characteristics of sinusoidal corrugated steel plates and the occurrence pattern of interactive buckling were investigated. For the calculation of shear buckling strength, a finite element program was used, and the analysis results were compared with the exact solution. In addition, the characteristics of buckling stress change and the change of buckling mode shape depending on corrugation thickness and shape parameter were analyzed, and by comparing these results with the results of a theoretical equation, the timing of buckling mode change was analyzed.

A Study on the Secondary Buckling of Plate Structure by Arc Length Method (호장증분법에 의한 판구조물의 2차좌굴거동에 관한 연구)

  • 고재용;최익창
    • Computational Structural Engineering
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    • v.11 no.4
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    • pp.209-218
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    • 1998
  • 고장력강이 구조강재로서 널리 사용되고 있다. 구조물의 극심한 하중을 받게되면 최종강도에 도달할 때까지 좌굴을 동반하게 된다. 그러므로, 고장력강판의 좌굴에 대한 정확한 평가가 중요한 설계기준이 되고 있다. 그러나, 고장력강을 효율적으로 사용하기 위해서는 좌굴허용설계를 도입할 수 있도록 판구조물의 판두께가 얇아져야 한다. 따라서, 박판구조물의 합리적인 설계를 하기 위해서는 좌굴후거동해석이 매우 중요하다. 그러므로, 본 논문에서는 호장증분법을 이용하여 압출하중을 받는 박판구조물의 초기좌굴후거동과 2차좌굴강도에 대하여 규명하였다. 특히, 호장증분법을 좌굴정에서의 하중경로를 추정하기 위하여 적용하였다.

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