• Title, Summary, Keyword: Buckling strength

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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.

Development of Empirical Equation for Prediction of Minimal Track Buckling Strength (곡선부 궤도의 최소좌굴강도 추정식의 개발)

  • Yang, Sin-Chu;Kim, Eun;Lee, Jee-Ha;Shin, Jung-Ryul
    • Proceedings of the KSR Conference
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    • pp.475-480
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    • 2001
  • In this study, a empirical equation which can be feasibly used to evaluate minimal track buckling strength without exact numerical analysis is presented. Parameter studies we carried out to investigate the effects of the individual factor on buckling strength. In order to simulate track buckling in the field as precisely as possible, a rigorous buckling model which accounts for all the important parameters is adopted. A empirical equation for prediction of minimal track buckling strength is derived by taking nonlinear regression of data which are obtained from numerical analyses. Its characteristics and applicability are investigated by comparing the results by the presented equation with the one by the equation which was presented in japan, and is frequently using in korea when designing track structure.

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Development of the Buckling Strength Assessment System based on Offshore Structure Design Code (해양구조물 설계코드에 기반한 좌굴강도 평가 시스템 개발)

  • Kim, Ul-Nyeon
    • Special Issue of the Society of Naval Architects of Korea
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    • pp.38-45
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    • 2017
  • FPSO is widely used to develop deep sea oil fields and HHI has constructed ten(10) FPSOs. During these constructions, relevant structural design criteria such as yielding, buckling, fatigue, collision and impact strength were applied to verify structural safety. To apply the buckling strength evaluation for structures, the critical buckling stresses and applied stresses of relevant panels should be calculated. The plate and stiffened panels are to be idealized, which are needed much time and efforts by designers. Therefore, program development is necessary in order to evaluate the buckling strength conveniently and accurately. In this study, the buckling strength assessment system by using offshore code, DNV-RP-C201 was developed under MSC/PATRAN, pre-post program of finite element method. Graphic user interface program is written in MSC/PATRAN PCL functions. Source program to evaluate the buckling strength is developed in FORTRAN programming languages. The developed program is verified by comparing with the results of the Nauticus Hull developed by DNV Classification Society, and applied to the marine construction project conducted by Hyundai Heavy Industries LTD.

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Post buckling mechanics and strength of cold-formed steel columns exhibiting Local-Distortional interaction mode failure

  • Muthuraj, Hareesh;Sekar, S.K.;Mahendran, Mahen;Deepak, O.P.
    • Structural Engineering and Mechanics
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    • v.64 no.5
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    • pp.621-640
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    • 2017
  • This paper reports the numerical investigation conducted to study the influence of Local-Distortional (L-D) interaction mode buckling on post buckling strength erosion in fixed ended lipped channel cold formed steel columns. This investigation comprises of 81 column sections with various geometries and yield stresses that are carefully chosen to cover wide range of strength related parametric ratios like (i) distortional to local critical buckling stress ratio ($0.91{\leq}F_{CRD}/F_{CRL}{\leq}4.05$) (ii) non dimensional local slenderness ratio ($0.88{\leq}{\lambda}_L{\leq}3.54$) (iii) non-dimensional distortional slenderness ratio ($0.68{\leq}{\lambda}_D{\leq}3.23$) and (iv) yield to non-critical buckling stress ratio (0.45 to 10.4). The numerical investigation is carried out by conducting linear and non-linear shell finite element analysis (SFEA) using ABAQUS software. The non-linear SFEA includes both geometry and material non-linearity. The numerical results obtained are deeply analysed to understand the post buckling mechanics, failure modes and ultimate strength that are influenced by L-D interaction with respect to strength related parametric ratios. The ultimate strength data obtained from numerical analysis are compared with (i) the experimental tests data concerning L-D interaction mode buckling reported by other researchers (ii) column strength predicted by Direct Strength Method (DSM) column strength curves for local and distortional buckling specified in AISI S-100 (iii) strength predicted by available DSM based approaches that includes L-D interaction mode failure. The role of flange width to web depth ratio on post buckling strength erosion is reported. Then the paper concludes with merits and limitations of codified DSM and available DSM based approaches on accurate failure strength prediction.

Simplified method for prediction of elastic-plastic buckling strength of web-post panels in castellated steel beams

  • Liu, Mei;Guo, Kangrui;Wang, Peijun;Lou, Chao;Zhang, Yue
    • Steel and Composite Structures
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    • v.25 no.6
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    • pp.671-684
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    • 2017
  • Elastic-plastic shear buckling behaviors of the web-post in a Castellated Steel Beam (CSB) with hexagonal web openings under vertical shear force were investigated further using Finite Element Model (FEM) based on a sub-model, which took the upper part of the web-post under horizontal shear force to represent the whole web-post under vertical shear force. A simplified design method for the web-post elastic-plastic shear buckling strength was proposed based on simulation results of the sub-model. Proper boundary conditions were applied to the sub-model to assure that its behaviors were identical to those of the whole web-post. The equation to calculate the thin plate elastic shear buckling strength was adopted as the basic form to build the design equation for elastic-plastic buckling strength of the sub-model. Parameters that might affect the elastic-plastic shear buckling strength of the whole web-post were studied. After obtaining the vertical shear buckling strength of a sub-model through FEM, the shear buckling coefficient k can be obtained through the back analysis. A practical calculation method for k was proposed through curving fitting the parameter study results. The elastic-plastic shear buckling strength of the web-post calculated using the proposed shear buckling coefficient k agreed well with that obtained from the FEM and test results. And it was more precise than those obtained from EC3 based on the strut model.

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 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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Elastic Buckling Characteristics of Corrugated Culverts of Orthotropic Material (직교 이방성 재료 파형 암거의 탄성 화굴 거동 특성)

  • Kim Tae-Yeon;Han Taek-Hee;Han Keum-Ho;Kang Jin-Ook;Lee Myeoung-Sub;Kang Young-Jong
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • pp.111-118
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    • 2006
  • The elastic buckling strength of a corrugated culvert made of orthotropic material such as FRP was evaluated. The height and length of a corrugated wave and the thickness of the culvert were considered as factors affecting the buckling strength of the culvert. And also, the ratio of the longitudinal stiffness and transverse stiffness was considered as the parameter affecting on the buckling strength of the used orthotropic material. Buckling strengths of various corrugated culvert models with different shapes and stiffness ratio were evaluated by FE analyses and a formula to estimate the elastic buckling strength was suggested from the regression with FE analysis results. Analysis results show that a corrugated culvert has superior buckling strength to a general flat pipe and the suggested formula estimates accurate buckling strength of the corrugated culverts made of orthotropic material.

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Elastic Behavior Characteristics of GFRP Pipes Reinforced Ribs (리브로 보강된 GFRP 관로의 탄성 좌굴거동 특성)

  • Han, Taek Hee;Seo, Joo Hyung;Youm, Eung Jun;Kang, Young Jong
    • Journal of Korean Society of Steel Construction
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    • v.18 no.6
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    • pp.737-746
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    • 2006
  • The elastic buckling strength of a Glass Fiber Reinforced Plastic (GFRP) pipe reinforced with ribs was evaluated. The height and thickness of a rib and the spacing between two adjacent ribs were considered as factors affecting the buckling strength of the pipe. And also, the ratio of the longitudinal stiffness and transverse stiffness was considered as the parameter affecting the buckling strength as the GFRP is orthotropic material. Buckling strengths of various GFRP pipe models with different shapes and stiffness ratios were evaluated by FE analyses and a formula to estimate the elastic buckling strength of a rib-reinforced pipe made of orthotropic material was suggested from the regression with the results from the FE analysis. Analytical results show that a rib-reinforced pipe has a buckling strength superior to a general flat pipe and the suggested formula estimates accurate buckling strength of the rib-reinforced pipe.

A Study on Buckling Strengths for Steel Compression Members at High Temperatures (고온 강구조 압축재의 좌굴 강도에 관한 연구)

  • Choi, Hyun-Sik
    • Journal of Korean Association for Spatial Structures
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    • v.19 no.2
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    • pp.73-81
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    • 2019
  • The high-temperature properties of mild steels were studied by comparing the test results of Kwon and the yield strength, tangent modulus predicted by the design provisions of ASCE and Eurocode(EC3). The column strengths for steel members at high temperatures were determined by the elastic and inelastic buckling strengths according to elevated temperatures. The material properties at high temperatures should be used in the strength evaluations of high temperature members. The buckling strengths obtained from the AISC, EC3 and approximate formula proposed by Takagi et al. were compared with ones calculated by the material nonlinear analysis using the EC3 material model. The newly simplified formulas for yield stress, tangent modulus, proportional limit and buckling strength which were proposed through a comparative study of the material properties and buckling strengths. The buckling strengths of proposed formulas were approximately equivalent to ones obtained from the formulas of Takagi et al. within 4%. They were corresponded to the lower bound values among the buckling strengths calculated by the design formulas and inelastic buckling analysis.

Tests and finite element analysis on the local buckling of 420 MPa steel equal angle columns under axial compression

  • Shi, G.;Liu, Z.;Ban, H.Y.;Zhang, Y.;Shi, Y.J.;Wang, Y.Q.
    • Steel and Composite Structures
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    • v.12 no.1
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    • pp.31-51
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    • 2012
  • Local buckling can be ignored for hot-rolled ordinary strength steel equal angle compression members, because the width-to-thickness ratios of the leg don't exceed the limit value. With the development of steel structures, Q420 high strength steel angles with the nominal yield strength of 420 MPa have begun to be widely used in China. Because of the high strength, the limit value of the width-to-thickness ratio becomes smaller than that of ordinary steel strength, which causes that the width-to-thickness ratios of some hot-rolled steel angle sections exceed the limit value. Consequently, local buckling must be considered for 420 MPa steel equal angles under axial compression. The existing research on the local buckling of high strength steel members under axial compression is briefly summarized, and it shows that there is lack of study on the local buckling of high strength steel equal angles under axial compression. Aiming at the local buckling of high strength steel angles, this paper conducts an axial compression experiment of 420MPa high strength steel equal angles, including 15 stub columns. The test results are compared with the corresponding design methods in ANSI/AISC 360-05 and Eurocode 3. Then a finite element model is developed to analyze the local buckling behavior of high strength steel equal angles under axial compression, and validated by the test results. Following the validation, a finite element parametric study is conducted to study the influences of a range of parameters, and the analysis results are compared with the design strengths by ANSI/AISC 360-05 and Eurocode 3.