• Title, Summary, Keyword: 좌굴 강도

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The Compressive Strength of Longitudinally Stiffened Plates Undergoing Local and Distortional Buckling (국부좌굴과 뒤틀림좌굴이 발생하는 종방향 보강재로 보강된 강판의 압축강도)

  • Park, Ho-Sang;Seo, Sang-Jung;Kwon, Young-Bong
    • Journal of Korean Society of Steel Construction
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    • v.22 no.3
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    • pp.219-228
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    • 2010
  • This paper describes an experimental research on the structural behavior and the ultimate strength of longitudinally stiffened plates subjected to local, distortional, or mixed-mode buckling under compression. The stiffened plate undergoes local, distortional, or interactive local-distortional buckling according to the flexural rigidity of the plate's longitudinal stiffeners and the width-thickness ratios of the sub-panels of the stiffened plate. A significant post-buckling strength in the local and distortional modes affects the ultimate strength of the longitudinally stiffened plate. Compression tests were conducted on stiffened plates that were fabricated from 4mm-thick SM400 steel plates with a nominal yield stress of 235MPa. A simple strength formula for the Direct Strength Method based on the test results was proposed. This paper proves that the Direct Strength Method can properly predict the ultimate strength of stiffened plates when the local buckling and distortional buckling occur simultaneously or nearly simultaneously.

A Study on the Moment Capacity of H-Section Flexural Members with Local Buckling (국부좌굴이 발생하는 H-형강 휨부재의 강도에 관한 연구)

  • Seo, Gun-Ho;Seo, Sang-Jung;Kwon, Young-Bong
    • Journal of Korean Society of Steel Construction
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    • v.23 no.6
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    • pp.647-657
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    • 2011
  • This paper describes the moment capacity of flexural members with local buckling based on a series of FE and experiment results. Thin-walled flexural members undergo local, lateral-torsional, or interactive buckling according to the section geometries and lateral boundary conditions. Flexural members with large width-to-thickness ratios in the flanges or the web may undergo local buckling before lateral-torsional buckling. Local buckling has a negative effect on the flexural strength based on the lateral-torsional buckling of flexural members. This phenomenon should be considered in the estimation of the flexural strength of thin-walled sections. Flexural members with various width-to-thickness ratios in their flanges and web were analyzed. Initial imperfections in the local buckling mode, and residual stresses, were included in the FE analyses. Simple bending moment formulae for flexural members were proposed based on the FE and test results to account for local and lateral-torsional buckling. The proposed bending moment formulae for the thin-walled flexural members in the Direct Strength Method use the empirical strength formula and the grosssection modulus. The ultimate flexural strengths predicted by the proposed moment formulae were compared with the AISC (2005), Eurocode3 (2003), and Korean Highway Bridge Design Specifications (2010). The comparison showed that the proposed bending moment formulae can reasonably predict the ultimate moment capacity of thin-walled flexural members.

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.

선체구조의 좌굴.최종강도에 관한 연구동향

  • 백점기
    • Computational Structural Engineering
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    • v.10 no.2
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    • pp.13-26
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    • 1997
  • 본 고에서는 선체구조의 좌굴 및 최종강도에 관한 연구현황을 조사 분석하고자 한다. 먼저 대표적인 구성부재인 판 및 보강판의 좌굴 최종강도에 관한 연구현황을 분석하고, 다음으로 선각거더의 최종붕괴강도에 관한 연구동향을 분석하고자 한다.

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The Development on the Buckling Strength Estimation Formula of Plate Members in Consideration of Inplane Tension(I) (면내인장력을 고려한 판부재의 좌굴강도 평가식 개발 (I))

  • Ham, Juh H.;Kim, Ul N.;Chung, Yun S.
    • Journal of the Society of Naval Architects of Korea
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    • v.33 no.2
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    • pp.111-118
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    • 1996
  • Ship structure basically consists of plate members and it's overall strength depends an the stiffness and strength of each plate member. The buckling strength of plate is one of the most important design criteria when we investigate the structural intergraty. Therefore, it is necessary to surly reasonable buckling formula in order to carry out a more efficient and reliable design. In the present study, the buckling design formula of plate panels under combined loads(inplane compression, tension and shear) is obtained on the theoretical solution or reference paper. This formula is compared with the existing theoretical solution, other author's formula[1], design codes of LR and results which are obtained by numerical analysis. It has a good correlation with numerical analysis results or theoretical ones. When we evaluate buckling strength of plate panels, this formula can be presented with reasonable accuracy.

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A Study on Elastic Shear Buckling Coefficients of Horizontally Curved Plate Girder Web Panels (강곡선 플레이트거더 복부판의 전단좌굴계수에 관한 연구)

  • Lee, Doo-Sung;Lee, Sung-Chul
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.3A
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    • pp.367-373
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    • 2008
  • In the design of horizontally curved plate girder web panels, it is required to evaluate accurately the elastic buckling strength under pure shear. Currently, elastic shear buckling coefficients of curved web panels stiffened by transverse intermediate stiffeners are determined by assuming conservatively that straight web panels without curvature are simply supported at the juncture between the flange and web. However, depending upon the geometry and the properties of the curved plate girder, the elastically restrained support may behave rather closer to a fixed support. The buckling strength of curved girder web is much greater (maximum 38%) than that of a straight girder calculated under the assumption that all four edges are simply supported in Lee and Yoo (1999). In the present study, a series of numerical analyses based on a 3D finite element modeling is carried out to investigate the effects of geometric parameters on both the boundary condition at the juncture and the horizontal curvature of web panel, and the resulting data are quantified in a simple design equation.

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Shear Design of Trapezoidally Corrugated Steel Webs (제형 파형강판 복부판의 전단 설계)

  • Moon, Jiho;Yi, Jongwon;Choi, Byung-Ho;Lee, Hak-Eun
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.4A
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    • pp.497-505
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    • 2008
  • Corrugated steel webs resist only shear force because of the accordion effects. The shear force in the web can cause three different buckling mode: local, global, and interactive shear buckling modes. The shear behavior of the corrugated steel webs have been investigated by several researchers. However, shear buckling behavior of the corrugated webs are not clearly explained yet. And, it lead the conservative design. This paper presents shear strength of trapezoidally corrugated steel webs. A series of the tests were also conducted to verified proposed shear strength. Firstly, local, global, and interactive shear buckling equations provided by previous researchers were rearranged as a simple form considering the profiles of the existing bridges with corrugated steel webs. And, global and interactive shear buckling coefficient, and shear buckling parameter for corrugated webs were suggested in this study. Inelastic buckling strength can be determined from buckling curves based on the proposed shear buckling parameter. From the test results of this study and those of previous researchers, it can be found that suggested shear strength provides good estimation of those of trapezoidally corrugated steel webs.

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Buckling Strength of Orthogonally Stiffened Steel Plates under Uniaxial Compression (일축압축을 받는 직교로 보강된 판의 좌굴강도)

  • Choi, Dong Ho;Chang, Dong Il;Choi, Hang Yong
    • Journal of Korean Society of Steel Construction
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    • v.10 no.4
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    • pp.731-740
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    • 1998
  • Orthogonally stiffened steel plates are used for orthotropic steel decks of long-span bridges because of high degree of flexural and torsional resistances and good load-distribution behavior. An analytic study is presented for evaluating the buckling strength of orthogonally stiffened plates subjected to uniaxial compression. By using the plate theory, the buckling stress under overall and partial buckling modes, is derived. Parametric studies are performed to show the effects of the stiffness and the number of transverse and longitudinal ribs on the buckling strength. The results show quantitatively strong influence of stiffness and spacing of longitudinal and transverse ribs.

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Buckling Sensitivity of Laminated Composite Pipes Under External Uniform Pressure Considering Ply Angle (등분포하중을 받는 복합재료 관로의 적층각 변화에 따른 좌굴 민감도 분석)

  • Han, Taek Hee;Na, Tae Soo;Han, Sang Yun;Kang, Young Jong
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.3
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    • pp.123-131
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    • 2007
  • The buckling behavior of a fiber reinforced plastic pipe was researched. When a cylindrical structure is made of isotropic material, it shows two dimensional buckled shape which has same deformed section along the longitudinal direction. But an anisotropic cylindrical structure shows three dimensional buckled shape which has different deformed section along the longitudinal direction. Because the modulus of elasticity is varied in a certain direction when ply angles are changed, the strength of a pipe are changed as ply angles are changed. In this study, the limitation of two dimensional and three dimensional buckling mode was investigated and the buckling strength of a laminated composite pipe was evaluated.

Approximate Solution for In-Plane Elastic Buckling of Shallow Parabolic Arches (낮은 포물선 아치의 탄성 면내좌굴에 관한 근사식)

  • Moon, Ji Ho;Yoon, Ki Yong;Yi, Jong Won;Lee, Hak Eun
    • Journal of Korean Society of Steel Construction
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    • v.18 no.4
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    • pp.427-436
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    • 2006
  • The classical buckling theory assumes that prebuckling behavior is linear and that the effect of prebuckling deformations on buckling can be ignored. However, when the rise to span ratio decreases, prebuckling deformation cannot be ignored and the symetrical buckling strength can be smaler than the asymetrical buckling strength. Finally, arches can fail due to snap-through buckling. This paper investigates the non-linear behavior and strength of pin-ended parabolic shallow arches using the non-linear governing differential equation of shallow arches. These results were compared with the solution for the symmetrical buckling load of pin-ended parabolic shallow arches was suggested.