• Title/Summary/Keyword: Buckling strength equation

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A Numerical Study on Inelastic lateral Torsional Buckling Strength of Doubly Stepped and Singly Symmetric I-Beam Subjected to Uniform Moment (균일모멘트가 작용하는 일축대칭 I형 양단 스텝보의 비탄성 횡-비틀림 좌굴에 관한 해석적 연구)

  • Park, Yi Seul;Park, Jong Sup
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.7
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    • pp.3495-3501
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    • 2013
  • The cross-sections of continuous multi-span beams are sometimes suddenly increased or stepped at the interior supports of continuous beams to resist high negative moments. This paper investigates inelastic lateral-torsional buckling of monosymmetric stepped I-beams subjected to pure bending. A three-dimensional finite-element program ABAQUS and a regression program were used to analytically develop new design equation. The flange thickness ratio, flange width ratio and stepped length ratio were considered as parameters of this study. The combined effects of residual stresses and geometric imperfection on inelastic lateral-torsional buckling of beams are considered. The proposed solution can be easily used to calculation for inelastic lateral torsional buckling strengths of monosymmetric beams with doubly stepped cross sections and to develop new design equations for inelastic lateral-torsional buckling resistances of stepped beams.

Design Equation of Reinforced Concrete Walls for Opening Configurations (개구부 형상을 고려한 철근콘크리트 벽체의 설계식 제안)

  • Lee, Dong-Jun;Oh, Soon-Taek
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.3
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    • pp.131-137
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    • 2010
  • 12 trial-scale wall panels are tested and evaluated to investigate the ultimate load capacity of axially loaded concrete walls with various opening configurations. The experimental tests have been undertaken to obtain data for the modification of existing equations. A new design equation has been generated using the precise test data and it incorporates the unique length factors. This new design equation for concrete walls with openings is then compared with existing code formulae.

Moment Gradient Factor for Lateral Torsional Buckling Strength of Monosymmetric Stepped I-beam Subjected to Uniform Moment

  • Gelera, Kathleen Mae;Park, Jong-Sup
    • Journal of the Korean Society of Hazard Mitigation
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    • v.10 no.2
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    • pp.7-13
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    • 2010
  • Stepped I-beams having increased moment of inertia at one end (singly stepped beam) or both ends (doubly stepped beams) can often be seen in construction of bridges due to material economy and easy fabrication of the section. This paper presents the results of the parametric study of lateral torsional buckling of monosymmetric stepped I-beams with constant depth subjected to uniform moment. Design recommendations were made based on the finite element results of the models having different combinations of monosymmetric ratio, stepped length ratio, flange thickness ratio and flange width ratio. The proposed approximation is acceptable based on the parameters given having mostly conservative results. The proposed equation can be further used to extend the study to different loading conditions.

Flexural Strength Design Equation of Concrete Filled Steel Tube(CFT) Column Reinforced by Carbon Fiber Sheet (탄소섬유쉬트로 보강한 콘크리트 충전강관(CFT) 기둥의 휨내력식)

  • Park, Jai-Woo;Hong, Young-Kyun;Hong, Gi-Soup
    • Journal of the Earthquake Engineering Society of Korea
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    • v.12 no.3
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    • pp.29-36
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    • 2008
  • The TR-CFT(Transversely Reinforced Concrete Filled Steel Tube) column is proposed to control or at least delay the state of local buckling at the critical section by wrapping the CFT columns with a carbon fiber sheet. In this study, an equation to determine the flexural strength of TR-CFT is proposed. The ACI-318 code, in which the contribution of the confining effect in the concrete filled steel tube is not appropriately accounted for, may be conservative. Therefore, flexural strength design equations for CFT columns and TR-CFT columns are proposed based on the concrete strain-stress curve, which contributes to the confining effect. Finally, the predicted results for the CFT and TR-CFT columns are shown to be in good agreement with actual test results.

Strength Evaluation of a Doubler Plate of Ship Structure subjected to the In-plane Combined Load and Lateral Pressure Load (면내 조합하중과 횡압을 받는 선박 이중판의 강도 평가)

  • Ham, Juh-Hyeok
    • Journal of the Society of Naval Architects of Korea
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    • v.40 no.6
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    • pp.37-48
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    • 2003
  • A study for the structural strength evaluation of doubler plates subjected to the in-plane combined load and lateral pressure load has been performed through a systematic evaluation process. In order to properly estimate the static strength of doubler plate, elasto-plastic large deflection analysis is introduced including the contact effect between main plate and doubler. The characteristics of stiffness and strength variation are discussed based on the analysis results. Also, in order to compare the doubler structure with the original strength of main plate without doubler, a simple formula for the evaluation of the equivalent flat plate thickness is derived based on the additional series analysis of fiat plate structure. Using this derived equation, the thickness change of a equivalent flat plate is analyzed according to the variation of various design parameters of doubler plate and some design guides are suggested In order to maintain the original strength of main plate without doubler reinforcement. Finally, correlation between derived equivalent plate thickness formula and the developed buckling strength formulas for intact plates by author et al. is discovered and these relations are formulated for the future development of simple strength evaluation formula of doubler plate structure.

Buckling Strength of Orthotropic Rectangular Plate with a Longitudinal Stiffener under In-plane Linearly Distributed Loads (면내 선형분포하중을 받는 수평보강재가 설치된 직교이방성판의 좌굴강도)

  • Jung, Jae Ho;Yoon, Soon Jong;Cho, Sun Kyu
    • Journal of Korean Society of Steel Construction
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    • v.10 no.3 s.36
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    • pp.393-406
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    • 1998
  • In this study buckling behavior of orthotropic plate with a longitudinal stiffener under in-plane linearly distributed loads is investigated. All edges of plate are assumed to be simply supported and the stiffener is considered as a beam element. For the equation of buckling analysis Rayleigh-Ritz method is employed. The upper limit of the critical stress at various location of stiffener is determined by using Lagrangian multiplier method. Buckling analysis is performed for the various position of stiffener and for the various width ratios between plate and stiffener. The parametric study shows that, when four edges of plate are simply supported, the most effective position for a longitudinal stiffener is at the location of which the upper limit of the stress is the maximum.

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Approximate Solution for Finding the Buckling Strength of Orthotropic Rectangular Plates (직교이방성판의 좌굴강도를 구하기 위한 근사식의 개발)

  • J. H. Jung;S. J. Yoon;S. K. You
    • Composites Research
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    • v.16 no.5
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    • pp.28-38
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    • 2003
  • In this study, the analytical investigation of orthotropic rectangular plate is presented. The loaded edges are assumed to be simply supported and the unloaded edges could have elastically restrained boundary conditions including the extreme boundary condition such as simple, fixed, and free. Using the closed-form solutions, the buckling analyses of orthotropic plate with arbitrary boundary conditions are performed. Based on the data obtained by conducting numerical analysis, the simplified form of equation for finding the buckling coefficient of plate with elastically restrained boundary conditions at the unloaded edges is suggested as a function of aspect ratio, elastic restraint. and material properties of the plate. The results of buckling analyses by closed-form solution and simplified form of solution are compared for various orthotropic material properties. It is confirmed that the difference of results is less than 1.5%.

Nonlinear numerical analysis and proposed equation for axial loading capacity of concrete filled steel tube column with initial imperfection

  • Ahmad, Haseeb;Fahad, Muhammad;Aslam, Muhammad
    • Structural Monitoring and Maintenance
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    • v.9 no.1
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    • pp.81-105
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    • 2022
  • The use of concrete filled steel tube (CFST) column is widely accepted due to its property of high axial load carrying capacity, more ductility and more resistant to earthquake specially using in bridges and high-rise buildings. The initial imperfection (δ) that produces during casting or fixing causes the reduction in load carrying capacity, this is the reason, experimental capacity is always less then theoretical one. In this research, the effect of δ on load carrying capacity and behavior of concrete filled steel tube (CFST) column have been investigated by numerically simulation of large number of models with different δ and other geometric parameters that include length (L), width (B), steel tube thickness (t), f'c and fy. Finite element analysis software ANSYS v18 is used to develop model of SCFST column to evaluate strength capacity, buckling and failure pattern of member which is applied during experimental study under cyclic axial loading. After validation of results, 42 models with different parameters are evaluated to develop empirical equation predicting axial load carrying capacity for different value of δ. Results indicate that empirical equation shows the 0 to 9% error for finite element analysis Forty-two models in comparison with ANSYS results, respectively. Empirical equation can be used for predicting the axial capacity of early estimating the axial capacity of SCFT column including 𝛿.

Optimal Lamination Design of Composite Cylinders using an Empirical Ultimate Pressure Load Formula (최종강도 경험식을 이용한 복합재 원통구조의 최적적층 설계)

  • Cho, Yoon Sik;Paik, Jeom Kee
    • Journal of the Society of Naval Architects of Korea
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    • v.56 no.4
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    • pp.316-326
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    • 2019
  • In this paper, a methodology is presented for determining the optimal lamination of composite cylindrical structures subject to hydrostatic pressure. The strength criterion in association with the process of optimal design is the buckling collapse of composite cylinders under hydrostatic pressure loads. An empirical formula expressed in the form of the Merchant-Rankine equation is used to calculate the ultimate strength of filament-wound composite cylinders where genetic algorithm is applied for determining the optimized stacking sequences. It is shown that the optimized lamination provides improved collapse pressure loads. It is concluded that the developed method would be useful for the optimal lamination design of composite cylindrical structures.

Simplified Estimation of the Ultimate Strength of Ship Panels using Statistical Data of Actual Ships (건조선 통계자료를 이용한 선박 판부재의 최종강도 간이추정)

  • Oi-H. Kim;Juh-H. Ham;Ul-N. Kim
    • Journal of the Society of Naval Architects of Korea
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    • v.30 no.4
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    • pp.127-135
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    • 1993
  • The ultimate strength formulas of ship panels are suggested in a simple and suitable form. Firstly, these formulas are derived from a full description of the variables that govern plate strength by using statistical data of actual ships. Secondly, under the assumption of plate mid-edge collapse using the Von-Mises' yield criterion and the new buckling formula, a general equation for the ultimate strength estimation is also derived. The existing test data are compared with these new formulas and a good correlation is shown.

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