• Title, Summary, Keyword: local buckling

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Elastic local buckling of thin-walled elliptical tubes containing elastic infill material

  • Bradford, M.A.;Roufegarinejad, A.
    • Interaction and multiscale mechanics
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    • v.1 no.1
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    • pp.143-156
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    • 2008
  • Elliptical tubes may buckle in an elastic local buckling failure mode under uniform compression. Previous analyses of the local buckling of these members have assumed that the cross-section is hollow, but it is well-known that the local buckling capacity of thin-walled closed sections may be increased by filling them with a rigid medium such as concrete. In many applications, the medium many not necessarily be rigid, and the infill can be considered to be an elastic material which interacts with the buckling of the elliptical tube that surrounds it. This paper uses an energy-based technique to model the buckling of a thin-walled elliptical tube containing an elastic infill, which elucidates the physics of the buckling phenomenon from an engineering mechanics basis, in deference to a less generic finite element approach to the buckling problem. It makes use of the observation that the local buckling in an elliptical tube is localised with respect to the contour of the ellipse in its cross-section, with the localisation being at the region of lowest curvature. The formulation in the paper is algebraic and it leads to solutions that can be determined by implementing simple numerical solution techniques. A further extension of this formulation to a stiffness approach with multiple degrees of buckling freedom is described, and it is shown that using the simple one degree of freedom representation is sufficiently accurate for determining the elastic local buckling coefficient.

Local buckling and shift of effective centroid of cold-formed steel columns

  • Young, Ben
    • Steel and Composite Structures
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    • v.5 no.2_3
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    • pp.235-246
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    • 2005
  • Local buckling is a major consideration in the design of thin-walled cold-formed steel sections. The main effect of local buckling in plate elements under longitudinal compressive stresses is to cause a redistribution of the stresses in which the greatest portion of the load is carried near the supporting edges of the plate junctions. The redistribution produces increased stresses near the plate junctions and high bending stresses as a result of plate flexure, leading to ultimate loads below the squash load of the section. In singly symmetric cross-sections, the redistribution of longitudinal stress caused by local buckling also produces a shift of the line of action of internal force (shift of effective centroid). The fundamentally different effects of local buckling on the behaviour of pin-ended and fixed-ended singly symmetric columns lead to inconsistencies in traditional design approaches. The paper describes local buckling and shift of effective centroid of thin-walled cold-formed steel channel columns. Tests of channel columns have been described. The experimental local buckling loads were compared with the theoretical local buckling loads obtained using an elastic finite strip buckling analysis. The shift of the effective centroid was also compared with the shift predicted using the Australian/New Zealand and American specifications for cold-formed steel structures.

Critical buckling load of chiral double-walled carbon nanotube using non-local theory elasticity

  • Chemi, Awda;Heireche, Houari;Zidour, Mohamed;Rakrak, Kaddour;Bousahla, Abdelmoumen Anis
    • Advances in nano research
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    • v.3 no.4
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    • pp.193-206
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    • 2015
  • The present paper investigate the elastic buckling of chiral double-walled carbon nanotubes (DWCNTs) under axial compression. Using the non-local elasticity theory, Timoshenko beam model has been implemented. According to the governing equations of non-local theory, the analytical solution is derived and the solution for non-local critical buckling loads is obtained. The numerical results show the influence of non-local small-scale coefficient, the vibrational mode number, the chirality of carbon nanotube and aspect ratio of the (DWCNTs) on non-local critical buckling loads of the (DWCNTs). The results indicate the dependence of non-local critical buckling loads on the chirality of single-walled carbon nanotube with increase the non-local small-scale coefficient, the vibrational mode number and aspect ratio of length to diameter.

An Analytical Study on the Local - global Interaction Buckling of Orthotropic I-Shape Compression Members (직교이방성 I-Shape 압축재의 국부-전체 상호좌굴에 관한 해석적 연구)

  • 김학군;정상균;윤순종
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.1-4
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    • 2000
  • This paper presents the analytical results of local - global interaction buckling of orthotropic I-shape compression members. Employing the equilibrium approach, the characteristic equation for local and global interaction buckling of I-shape compression member is derived. Using the derived equation, the buckling coefficients with respect to the ratio of length to width for the I-shape column are suggested as a graphical form. In addition, graphical forms of local, global and FEM results are presents, and they are compared with those in published document.

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Local Buckling Behavior of Pultruded Structural Flexural Members (펄트루젼 구조용 휨부재의 국부좌굴 거동)

  • 정재호;윤순종
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.147-151
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    • 2003
  • In this study, we discussed the local buckling behavior of pultruded structural flexural members. Previous works were briefly reviewed and the local buckling behavior of orthotropic box-shape flexural members was discussed. The simplified form of equation for finding the width ratio of plate element of box-shape flexural members in which all plate components buckle simultaneously was proposed and the macro flow-chart for finding local buckling strength of pultruded flexural members was also suggested. To establish the design guide line for the local buckling of pultruded flexural members, further studies need to be performed as follows; the simplified form of solutions for finding the minimum buckling coefficient of orthotropic plate with various loading and boundary conditions including rotationally restrained boundary conditions, the simplified form of equation for calculating the coefficient of restraint provided by the adjacent plate elements.

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Local Buckling Characteristics of a column with I section (I형강기둥의 국부좌굴 특성)

  • 임종완;임장근
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.4
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    • pp.18-26
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    • 1994
  • The buckling characteristics of I - shaped columns which are composed of thin web and equal upper/lower flange plates are generally classified into the local and global modes. In this paper, its local buckling problem has been formulated on the basis of the assumed buckling modes using the finite element method for beams and plates. The effects of local bucklings are studied for various size rations and end conditions of I-shaped columns. The calculated results are comparatively well consistent with values obtained from the existing studies. The global buckling characteristics calculated by the present method are in good agreement with the classical rigid web solution

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Effect of local web buckling on the cyclic behavior of reduced web beam sections (RWBS)

  • Akrami, Vahid;Erfani, Saeed
    • Steel and Composite Structures
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    • v.18 no.3
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    • pp.641-657
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    • 2015
  • Application of reduced web beam section (RWBS) as a sacrificial fuse element has become a popular research field in recent years. Weakening of beam web in these connections may cause local web buckling around the opening area which can affect cyclic behavior of connection including: maximum load carrying capacity, strength degradation rate, dissipated energy, rotation capacity, etc. In this research, effect of local web buckling on the cyclic behavior of RWBS connections is investigated using finite element modeling (FEM). For this purpose, a T-shaped moment connection which has been tested under cyclic loading by another author is used as the reference model. Fracture initiation in models is simulated using Cyclic Void Growth Model (CVGM) which is based on micro-void growth and coalescence. Included in the results are: effect of opening corner radii, opening dimensions, beam web thickness and opening reinforcement. Based on the results, local web buckling around the opening area plays a significant role on the cyclic behavior of connection and hence any parameter affecting the local web buckling will affect entire connection behavior.

Distortional and local buckling of steel-concrete composite box-beam

  • Jiang, Lizhong;Qi, Jingjing;Scanlon, Andrew;Sun, Linlin
    • Steel and Composite Structures
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    • v.14 no.3
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    • pp.243-265
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    • 2013
  • Distortional and local buckling are important factors that influences the bearing capacity of steel-concrete composite box-beam. Through theoretical analysis of distortional buckling forms, a stability analysis calculation model of composite box beam considering rotation of steel beam top flange is presented. The critical bending moment calculation formula of distortional buckling is established. In addition, mechanical behaviors of a steel beam web in the negative moment zone subjected separately to bending stress, shear stress and combined stress are investigated. Elastic buckling factors of steel web under different stress conditions are calculated. On the basis of local buckling analysis results, a limiting value for height-to thickness ratio of a steel web in the elastic stage is proposed. Numerical examples are presented to verify the proposed models.

Identification of Dominant Plate Component for Local Buckling of Orthotropic I-Shape Compression Member (직교이방성 I형 단면 압축재의 국부좌굴 주도요소판별)

  • 김학군;채수하;정상균;윤순종
    • Proceedings of the Korean Society For Composite Materials Conference
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    • pp.9-14
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    • 2000
  • This paper presents the analytical results of local buckling of orthotropic I-shape compression members. Employing the equilibrium approach, the characteristic equation for local buckling of I-shape compression member is derived. Using the derived equation, the minimum buckling coefficients with respect to the ratio of width to thickness for the I-shape column are suggested as a graphical form. In addition, the dominant plate component initiating the local buckling of I-shape column is also identified by using the approximate solution and the results are plotted with dotted line on the minimum bucking coefficient curve.

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A Study on the Design Criteria Relating to the Local Buckling of Pultruded FRP Structural Compression Members (펄트루젼 구조압축재의 국부좌굴 설계규준 개발에 관한 연구)

  • Joo, Hyung Joong;Lee, Seung Sik;Yoon, Soon Jong
    • Journal of Korean Society of Steel Construction
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    • v.18 no.5
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    • pp.597-606
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    • 2006
  • Since FRP materials have various advantages over steel, many research activities to use them for the civil engineering applications are now in progress. The present paper deals with the local buckling behavior of FRP pultruded members as a first step toward the development of design criteria. In the design of compression members, it is very important to know not only if local buckling occurs or not but also which plate component governs local buckling, but it is not easy to perform this work in a rigorous manner. In the present paper, a simple and accurate equation which can compute the coefficients of buckling of orthotropic plates and local buckling of pultruded compression members is suggested by performing rigorous analysis, energy analysis, and parametric study. The local buckling strength and the plate component governing the local buckling behavior of thin-walled pultruded compression members can be easily determined by using the proposed equation.