• Journal of Auto-vehicle Safety Association
• /
• v.11 no.1
• /
• pp.40-47
• /
• 2019

First, three point bending analysis for the inclined press door impact beam was carried out to investigate inclination angle effect on the maximum strength with varying support distance. Next, for the system model with spring elements representing body stiffness at door mounting area, the bending structural behavior of impact beam mounted on vehicle was estimated. The mounting distance and inclination angle were changed and the beam bending buckling strength was presumed at the head displacement below which spring stiffness change has little effect on the load. Finally strength ratio to predict the bending buckling strength of impact beam mounted on vehicle from three point bending maximum strength of fixed support distance was suggested.

• Steel and Composite Structures
• /
• v.16 no.3
• /
• pp.325-337
• /
• 2014

The strength and buckling problem of a five layer sandwich beam under axial compression or bending is presented. Two faces of the beam are thin aluminium sheets and the core is made of aluminium foam. Between the faces and the core there are two thin binding glue layers. In the paper a mathematical model of the field of displacements, which includes a share effect and a bending moment, is presented. The system of partial differential equations of equilibrium for the five layer sandwich beam is derived on the basis of the principle of stationary total potential energy. The equations are analytically solved and the critical load is obtained. For comparison reasons a finite element model of the beam is formulated. For the case of bended beam the static analysis has been performed to obtain the stress distribution across the height of the beam. For the axially compressed beam the buckling analysis was carried out to determine the buckling load and buckling shape. Moreover, experimental investigations are carried out for two beams. The comparison of the results obtained in the analytical and numerical (FEM) analysis is shown in graphs and figures. The main aim of the paper is to present an analytical model of the five layer beam and to compare the results of the theoretical, numerical and experimental analyses.

• Journal of Korean Association for Spatial Structures
• /
• v.7 no.3 s.25
• /
• pp.119-124
• /
• 2007

Due to the deficit of section of web, the buckling strength of cellular beam become smaller than that of H-beam. In this thesis, we evaluate the buckling strength of web-post through non-linear F.E.M with opening distance-diameter ratio and opening diameter - web thickness ratio as essential variables. And also analyzes this comparing with the standard indicated in BS5950 Part 1.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.4 no.3
• /
• pp.145-152
• /
• 2000

In simply supported composite beams, the neutral axis of the composite cross section is usually located near the top flange of the steel H-shape, so that the top flange does not impart much strength to the member. This suggests that omitting the top flange entirely could be a means to lower the cost of the beam without greatly reducing the strength. However, It is not easy for inverted T-shaped composite beam to construct and to apply continuous beam which has negative bending moment. As a result, it would get more workability and decrease capability of lateral buckling and local buckling, if the bottom flange of inverted T-shaped steel used as a form. Therefore. the objectives of this study are to investigate strength and behaviors of inverted T-shaped composite beam which web is encased by concrete and to grasp bending capacity and efficiency of composite by comparing and analyzing in test piece.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.10 no.8
• /
• pp.2038-2043
• /
• 2009

This study investigates elastic lateral-torsional buckling(LTB) of T-beams subjected to pure bending using finite element analysis(FEA). The results from the FEA are compared with those from the current American Institute of Steel Council(AISC) Load and Resistance Factor Design(LRFD) Specifications. The comparison indicates that AISC-LRFD provide unsafe values for T-beam subjected to pure bending. Therefore, a new design equation are presented using results from the FEA. The new equation could be easily used to calculate the elastic lateral-torsional buckling moment resistance of T-beam for beam design and to expand the new equation for developing LTB equations of T-beam subjected to general loading conditions such as a concentrated load, distributed load, or a seres of concentrated load.

• Steel and Composite Structures
• /
• v.4 no.5
• /
• pp.367-384
• /
• 2004

A numerical model based on the finite element technique is adopted to investigate the behavior and strength of thin-walled I-section beam-columns. The model considers both the material and geometric nonlinearities. The model results were first verified against some of the currently available experimental results. A parametric study was then performed using the numerical model and interaction diagrams for the investigated beam-columns have been presented. The effects of the web depth-to-thickness ratio, flange outstand-to-thickness ratio and bending moment-to-normal force ratio on the ultimate strength of thin-walled I-section beam-columns were scrutinized. The interaction equations adopted for beam columns design by the NAS (North American Specifications for the design of cold formed steel structural members) have been critically reviewed. An equation for the buckling coefficient which considers the interaction between local buckling of the flange and the web of a thin-walled I-section beam-column has been proposed.

• Journal of Industrial Technology
• /
• v.4
• /
• pp.29-35
• /
• 1984

Buckling is a significant behavior to be considered whenever we design steel structures. In the case of H-shape beams, the lateral buckling occured by bending moment must be considered. Because of the lateral buckling of H-shape beams, the bending strength of the beams are determined by the lateral buckling stress instead of the allowable bending stress. Lateral buckling stress equation, consisting of two terms, i. e. ${\sigma}_{cr}({\nu},{\omega})={\sqrt{[{\sigma}_{cr}({\nu})]^2+[{\sigma}_{cr}({\omega})]^2}}$ has been using, but for the practical purpose of use the following equations are using two, i. e. ${\sigma}_{cr}({\nu})={\frac{0.65E}{{\ell}_h/A_f}}$, ${\sigma}_{cr}({\omega})={\frac{{\pi}^2E}{({\ell}_b/i_b)^2}}$. When we use the above equations, the results are different according to the shape of beam section, and they a re rather complex. In this study lateral buckling stress equation is derived, and the proposed formula$({\sigma}_{cr}(t))$ is compared with above mentioned two basic and practical equations. To verify the proposed formula experimentaly, 16H-shape beams which have different slender ratios arc tested by applying pure bending momet. Through the experiments the buckling behavior of H-shape beams is clarified, and the results shows that the proposed formula$({\sigma}_{cr}(t))$ is accurate enough for practical purpose.

• Structural Engineering and Mechanics
• /
• v.15 no.5
• /
• pp.495-511
• /
• 2003

New material applications and transparency are desired by contemporary architects. Its superb transparency and high strength make glass a very suitable building material -in spite of its brittleness- even for primary load bearing structures. Currently we will focus on load bearing glass beams, subjected to different loading types. Since glass beams have a very slender, rectangular cross section, they are sensitive to lateral torsional buckling. Glass beams fail under a critical buckling load at stresses that lie far below the theoretical simple bending strength, due to the complex combination of torsion and out-of-plane bending, which characterises the instability phenomenon. The critical load can be increased considerably by preventing the upper rim from moving out of the beam's plane. Different boundary conditions are examined for different loading types. The load carrying capacity of glass beams can be increased three times and more using relatively simple, cheap lateral restraints.

• Structural Engineering and Mechanics
• /
• v.48 no.2
• /
• pp.275-289
• /
• 2013

The cross sections of multi-span beams are sometimes suddenly increased at the interior support of continuous beams to resist high negative moment. An earlier study on elastic lateral torsional buckling of stepped beams was conducted to propose new design equations. This research aims to continue the earlier study by considering the effect of inelastic buckling of stepped beams subjected to pure bending and general loading condition. A three-dimensional finite element-program ABAQUS and a statistical program MINITAB were used in the development of new design equations. The inelastic lateral torsional buckling strengths of 36 and 27 models for singly and doubly stepped beams, respectively, were investigated. The general loading condition consists of 15 loading cases based on the number of inflection point within the unbraced length of the stepped beams. The combined effects of residual stresses and geometrical imperfection were also considered to evaluate the inelastic buckling strengths. The proposed equations in this study will definitely improve current design methods for the inelastic lateral-torsional buckling of stepped beams and will increase efficiency in building and bridge design.

• Proceedings of the KSR Conference
• /
• 2000.05a
• /
• pp.439-446
• /
• 2000

In this study, 7 dof (Including warping) beam element was developed to estimate the effects of wagner effects and load height effects on the lateral buckling strength of mono-symmetric I beam. Finite element buckling analysis of mono-symmetric I-shaped girders subjected to transverse loading applied at different heights on the cross-section were conducted. Linear moment gradient were considered, too. In these cases, girders are subjected to both single-curvature and Reverse-curvature bending. An applicability of current LRFD C$\sub$b/ on the mono-symmetric I beam was studied from the finite element results. The problems of current LRFD C$\sub$b/ occurring from load height effects and reverse curvature bending in unbraced length when applied on the mono-symmetric I beam were studied. Solutions to these problems are also presented.