• Title, Summary, Keyword: Member buckling

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Critical Load and Effective Buckling Length Factor of Dome-typed Space Frame Accordance with Variation of Member Rigidity (돔형 스페이스 프레임의 부재강성변화에 따른 임계좌굴하중과 유효좌굴길이계수)

  • Shon, Su-Deok;Lee, Seung-Jae
    • Journal of the Korean Association for Spatial Structures
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    • v.13 no.1
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    • pp.87-96
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    • 2013
  • This study investigated characteristics of buckling load and effective buckling length by member rigidity of dome-typed space frame which was sensitive to initial conditions. A critical point and a buckling load were computed by analyzing the eigenvalues and determinants of the tangential stiffness matrix. The hexagonal pyramid model and star dome were selected for the case study in order to examine the nodal buckling and member buckling in accordance with member rigidity. From the numerical results, an effective buckling length factor of adopted models was bigger than that of Euler buckling for the case of fixed boundary. These numerical models indicated that the influence of nodal buckling was greater than that of member buckling as member rigidity was higher. Besides, there was a tendency that the bifurcation appeared on the equilibrium path before limit point in the member buckling model.

Reinforcement Effects of Buckling Member for Single-layer Latticed Dome (단층래티스 돔의 좌굴부재 보강효과에 관한 연구)

  • Jung, Hwan-Mok;Yoon, Seok-Ho;Lee, Dong-Woo
    • Journal of the Korean Association for Spatial Structures
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    • v.16 no.4
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    • pp.45-52
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    • 2016
  • The single layer latticed domes have attracted many designers and researchers's attention all of the world, because these structures as spatial structure are of great advantage in not only mechanical rationality but also function, fabrication, construction and economic aspect. But single layer latticed domes are apt to occur the unstable phenomena that are called "buckling" because of the lack of strength of members, instability of structural shape, etc. In the case of latticed dome, there are several types of buckling mode such as overall buckling, local buckling, and member buckling according to the shape of dome, section type of member, the size of member, junction's condition of member and so on. There are many methods to increase the buckling strength of the single layer latticed dome, that is, with the change of geometrical shape of dome, the reinforcement of buckled member, etc. Therefore, the purpose of this study is to verify the reinforcement effect of buckled member when designers reinforce the buckled member to increase the buckling strength of single layer latticed dome with 3-way grid.

A Study on Buckling Characteristics of Arch-type Vinyl House Structures according to Analytical Precision (아치형 비닐하우스 구조의 해석정밀도에 따른 좌굴특성 연구)

  • Yoon, Seok-Ho
    • Journal of the Korean Association for Spatial Structures
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    • v.15 no.4
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    • pp.57-64
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    • 2015
  • The construction of vinyl greenhouses are increasing because of economic feasibility, construction period, and construction regulations. However, the vinyl greenhouses are apt to collapse by snow load since they have a small member as a temporary structure. The 3 types of buckling such as global, member and nodal buckling could be occurred to arched structures according to characteristics of cross section. To examine the member buckling, the precision of analysis need to be enhanced. In that case, we can examine the characteristics of the those buckling. The purposes of this study are to verify buckling characteristics of structures using the method of high precision analysis with a center node of member. The results of high precision analysis bring member buckling, and in the analysis method having the center node of member, the value of strength is getting lower than a previous study.

Local and global buckling condition of all-steel buckling restrained braces

  • Mirtaheri, Seyed Masoud;Nazeryan, Meissam;Bahrani, Mohammad Kazem;Nooralizadeh, Amin;Montazerian, Leila;Naserifard, Mohamadhosein
    • Steel and Composite Structures
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    • v.23 no.2
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    • pp.217-228
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    • 2017
  • Braces are one of the retrofitting systems of structure under earthquake loading. Buckling restrained braces (BRBs) are one of the very efficient braces for lateral loads. One of the key needs for a desirable and acceptable behavior of buckling-restraining brace members under intensive loading is that it prevents total buckling until the bracing member tolerates enough plastic deformation and ductility. This paper presents the results of a set of analysis by finite element method on buckling restrained braces in which the filler materials within the restraining member have been removed. These braces contain core as the conventional BRBs, but they have a different buckling restrained system. The purpose of this analysis is conducting a parametric study on various empty spaces between core and restraining member, the effect of friction between core and restraining member and applying initial deformation to brace system to investigate the global buckling behavior of these braces. The results of analysis indicate that the flexural stiffness of restraining member, regardless of the amount of empty space, can influence the global buckling behavior of brace significantly.

An Estimation of Buckling-Strength of Braced Rectangular Latticed Domes (브레이스로 보강된 사각형 래티스돔의 좌굴내력 평가)

  • Hwang, Young-Min;Suk, Chang-Mok;Park, Sang-Hoon
    • Journal of the Korean Association for Spatial Structures
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    • v.3 no.4
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    • pp.69-76
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    • 2003
  • In case of rectangular latticed pattern which shearing rigidity is very small, it has a concern to drop Buckling-strength considerably by external force. So, by means of system to increase buckling-strength, there is a method of construction that lattice of dome is reinforced by braced member. In a case like this, shearing rigidity of braced member increase buckling-strength of the whole of structure and can be designed economically from the viewpoint of practice. Therefore, this paper is aimed at investigating how much does rigidity of braced member united with latticed member bearing principal stress of dome increase buckling-strength of the whole of structure. the subject of study is rectangular latticed domes that are a set of 2-way lattice dome which grid is simple and number of member gathering at junction is small. Analysis method is based on FEM dealing with the geometrically nonlinear deflection problems.

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Effects of geometrical initial imperfection in proportioning member sections of single layer reticulated dome (단층 래티스 돔의 단면산정에 있어서의 형상초기불완전의 영향)

  • Kim, Jong-Min;HwangBo, Seok;Han, Sang-Eul;Kwun, Teak-Jin
    • 한국공간정보시스템학회:학술대회논문집
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    • pp.83-88
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    • 2004
  • First author proposed a proportioning method for member sections of a single layer reticulated dome subjected to uniform and non-uniform load without any geometrical initial imperfection, and discussed the validity and effectiveness of the method which was based on linear buckling stress and a knock down factor. However, buckling of a single layer reticulated dome is strongly affected by initial imperfection. It is well known that geometrical initial imperfections reduce the nonlinear buckling capacity of a single layer raticulated dome. Thus, structural engineers may be recommended to reflect the effects of geometrical initial imperfections in proportioning member sections. In this paper, firstly, the presented proportioning method by first author is applied to dome without consideration of any imperfections and the thickness and diameter of each member are determined. Secondly, the load bearing capacities of the proportioned domes are checked with the imperfection, by the inelastic buckling analysis.

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Modeling and prediction of buckling behavior of compression members with variability in material and/or section properties

  • Gadalla, M.A.;Abdalla, J.A.
    • Structural Engineering and Mechanics
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    • v.22 no.5
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    • pp.631-645
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    • 2006
  • Buckling capacity of compression members may change due to inadvertent changes in the member section dimensions or material properties. This may be the result of repair, modification of section properties or degradation of the material properties. In some occasions, enhancement of buckling capacity of compression members may be achieved through splicing of plates or utilization of composite materials. It is very important for a designer to predict the buckling resistance of the compression member and the important parameters that affect its buckling strength once changes in section and/or material properties took place. This paper presents an analytical approach for determining the buckling capacity of a compression member whose geometric and/or material properties has been altered resulting in a multi-step non-uniform section. This analytical solution accommodates the changes and modifications to the material and/or section properties of the compression member due to the factors mentioned. The analytical solution provides adequate information and a methodology that is useful during the design stage as well as the repair stage of compression members. Three case studies are presented to show that the proposed analytical solution is an efficient method for predicting the buckling strength of compression members that their section and/or material properties have been altered due to splicing, coping, notching, ducting and corrosion.

A Study on the Estimation of Elasto-Plastic Buckling Loads for Sing1e Layer Latticed Domes by Unit Member Modeling Technique. (단위부재 모델화에 따른 단층 래티스 돔의 탄소성 좌골하중의 산정에 관한 연구)

  • 한상을;이상주;유용주;이경수
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.290-297
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    • 1998
  • In this paper, we propose to a method to estimate the elasto-plastic buckling for single layer latticed domes. First, we assume that each member consists of the rigid zone and elastic spring at both end joint, the elastic element and three elasto-plastic spring to judge for yeilding the member. Next, the member which has most influence on buckling for structures is determined by a distributed pattern of the strain energy which is calculated through linear eigenvalue analysis. And then, normalized slenderness ratio of the element is derived considering the axial force at elastic buckling load. Later, we execute elasto-plastic nonlinear analysis that based on loading increasement method and displacement increasement method. From this results, we discusses the effect of the joint rigidity and the half open angle $\theta$$_{0}$ on the buckling strength of single layer lattice domes ; (1) how the joint rigidity contributes to the reduction of buckling loads, (2) how the reduction can be interrelated to compressive strength curves in terms of the generalized slenderness for the member most relevant to the overall buckling of domes.s.

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The Study on the Buckling Characteristics of Partially Increased Sectional Area for Compressed Circular Steel Tube (압축을 받는 강관의 단면보강에 따른 좌굴특성 검토)

  • 권영환;정환목;박상훈;석창목
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.187-193
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    • 1999
  • As the slenderness ratio increases, it is necessary to examine the increased sectional area of member by means of increasing buckling strength because the sectional area of compressive member is designed in accordance with buckling. In this reason tn reinforce insufficient strength it don not have to reinforce the whole sectional area of member. Force of member can be increased in a way to restrict buckling mode by means of the partially increased sectional area of member. Therefore, in this study, we put emphasis on compressive members among many members that constitute space frame and try to get basic data about the reinforcement of space frame by means of investigating the bucking characteristic according to the size and length of partially increased sectional area of member.

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A method for analyzing the buckling strength of truss structures

  • Pan, Yi;Gu, Renqi;Zhang, Ming;Parke, Gerry;Behnejad, Alireza
    • Earthquakes and Structures
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    • v.16 no.2
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    • pp.129-139
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    • 2019
  • This paper develops a new method for estimating the elastic-plastic buckling strength of the truss structures under the static and seismic loads. Firstly, a new method for estimating the buckling strength of the truss structures was derived based on the buckling strength of the representative member considering the parameters, such as the structure configurations, boundary conditions, etc. Secondly, the new method was verified through the buckling strength estimation and the finite element method (FEM) analysis of the single member models, portal frame models and simple truss models. Finally, the method was applied to evaluate the buckling strength of a simple truss structure under seismic load, and the failure loads between the proposed method and the FEM were analyzed reasonably. The results show that the new method is feasible and reliable for structure engineers to estimate the buckling strengths of the truss structures under the static loads and seismic loads.