Elastic Flexural-Torsional Buckling of Beam-Column with Equal-Leg Angle Cross-Section

2013 ◽  
Vol 353-356 ◽  
pp. 3151-3154
Author(s):  
Jian Qin ◽  
Yong Jun Xia ◽  
Jin Miao Zhang ◽  
Chun Hua Hu
Keyword(s):  
Numerical Methods ◽  
Engineering Design ◽  
Cross Section ◽  
Computational Efficiency ◽  
Slenderness Ratio ◽  
Governing Equations ◽  
Torsional Buckling ◽  
Buckling Loads ◽  
Beam Columns ◽  
Flexural Torsional Buckling

The flexural-torsional buckling of equal-leg angle member under compression is analyzed and calculated. Based on General bending theory and the section properties of angle, the governing equations of the spatial buckling are presented and the formula of Wagner effect coefficient is deduced. The method can also be used for beam-columns with any type section, and the computational efficiency is much higher than numerical methods. The critical buckling loads of equal-leg angle members with different sizes are calculated and the column curves of critical load and slenderness ratio are plotted which will guide efficiently the actual engineering design.

Flexural-Torsional Buckling of Pultruded Fiber-Reinforced Polymer Angle Beams under Eccentric Loading

2020 ◽  
Vol 982 ◽  
pp. 201-206
Author(s):  
Jaksada Thumrongvut ◽  
Natthawat Pakwan ◽  
Samaporn Krathumklang
Keyword(s):  
Buckling Load ◽  
Fiber Reinforced Polymer ◽  
Width Ratio ◽  
Fiber Reinforced ◽  
Torsional Buckling ◽  
Eccentric Load ◽  
Buckling Loads ◽  
Reinforced Polymer ◽  
Cross Sectional Dimension ◽  
Flexural Torsional Buckling

In this paper, the experimental study on the pultruded fiber-reinforced polymer (pultruded FRP) angle beams subjected to transversely eccentric load are presented. A summary of critical buckling load and buckling behavior for full-scale flexure tests with various span-to-width ratios (L/b) and eccentricities are investigated, and typical failure mode are identified. Three-point flexure tests of 50 pultruded FRP angle beams are performed. The E-glass fibre/polyester resin angle specimens are tested to examine the effect of span-to-width ratio of the beams on the buckling responses and critical buckling loads. The angle specimens have the cross-sectional dimension of 76x6.4 mm with span-to-width ratios, ranging from 20 to 40. Also, four different eccentricities are investigated, ranging from 0 to ±2e. Eccentric loads are applied below the horizontal flange in increments until beam buckling occurred. Based upon the results of this study, it is found that the load and mid-span vertical deflection relationships of the angle beams are linear up to the failure. In contrast, the load and mid-span lateral deflection relationships are geometrically nonlinear. The general mode of failure is the flexural-torsional buckling. The eccentrically loaded specimens are failed at critical buckling loads lower than their concentric counterparts. Also, the quantity of eccentricity increases as buckling load decreases. In addition, it is noticed that span-to-width ratio increases, the buckling load is decreased. The eccentric location proved to have considerable influence over the buckling load of the pultruded FRP angle beams.

Effects of Changing Double Angles Configuration Used as Braces in Seismic Resisting Systems

2018 ◽  
Vol 763 ◽  
pp. 279-286
Author(s):  
Carlos Bermudez ◽  
Oscar Gutierrez
Keyword(s):  
Compressive Strength ◽  
Slenderness Ratio ◽  
Limit State ◽  
Experimental Results ◽  
Limit States ◽  
Torsional Buckling ◽  
Critical Limit ◽  
Flexural Buckling ◽  
Flexural Torsional Buckling ◽  
Buckling Length

Seismic resisting systems consisting of double angles are used in many parts of the world. Generally, these double angles are arranged in the shape of a T, with a very small distance between them. However, sometimes these angles are distanced and faced in order to improve their mechanical characteristics about the axis of symmetry. In the past, their design was made in the same way as the double angles arranged in a T shape, that is, considering the limit states of flexural buckling and buckling by flexural-torsional, but ignoring the properties of the connectors and their effect on the modified slenderness ratio, as well as the fact that in this case the warping constant is not negligible. These parameters are taken into account in this research in order to study the effects of increasing the distance between the connectors and their possible use as braces in seismic resisting systems. The theoretical results were compared with the experimental results of fifty-seven specimens tested in the laboratory of structures of the Universidad Nacional de Colombia – Sede Manizales. The models were classified according to the main angles, the connectors, the total lengths, and the width of separation. All of them were subjected to axial compressive stress, with free rotation at both ends. Three identical specimens of each model were constructed. The flexural buckling length about x-axis was limited to two meters in all specimens tested whereas the flexural bucking length about y-axis and flexural-torsional buckling length were not limited, i.e. these lengths are equivalent to the total length of each specimen tested. This in order that the critical limit state was to be the flexural-torsional buckling as a function of the torsional buckling term in Z, except in the models of class 2 in which this induced condition was not reached. This was proposed to better evaluate the torsional buckling term in Z. The experimental results show that the nominal compressive strength for the flexural-torsional buckling limit state, when it is governed by torsion, is undervalued. A new methodology is proposed for the calculation of the nominal compressive strength for the flexural-torsional buckling limit state, when it is governed by torsion.

Torsional Buckling of the Hubble Space Telescope Solar Arrays

1998 ◽  
Vol 13 (2) ◽  
pp. 65-74
Author(s):  
Earl A. Thornton ◽  
David L Eby ◽  
Peter W. Chung
Keyword(s):  
Cross Section ◽  
Hubble Space Telescope ◽  
Solar Array ◽  
Torsional Buckling ◽  
Buckling Loads ◽  
Space Telescope ◽  
Linear Elastic ◽  
Solar Arrays ◽  
Buckling Behavior ◽  
Open Cross Section

The buckling behavior of a flexible rolled-up solar array used on the Hubble Space Telescope (HST) is investigated analytically and experimentally. Analytically, the solar array is modeled assuming the booms are linear, elastic beams of open cross-section, and the solar blanket is represented as an inextensible membrane. The analyses determine critical buckling loads for flexure and torsion. The behavior of the solar array is also investigated by experiments conducted using a model solar array with (1) closed cross-section booms, and (2) tubular booms like those used on the HST. The analyses and experiments show that the Hubble's solar arrays were deployed with a preload that caused them to buckle in torsion. Based on the study, an hypothesis is suggested for the failure of the solar array's booms that was discovered by the astronauts in 1993.

Thin-Walled Cold-Formed Steel Beams with Holes in Lateral Flexural-Torsional Buckling

2013 ◽  
Vol 743 ◽  
pp. 170-175 ◽  
Author(s):  
Marcela Karmazínová ◽  
Jindrich Melcher ◽  
Martin Horáček
Keyword(s):  
Cross Section ◽  
Stability Problem ◽  
Design Procedure ◽  
Steel Structures ◽  
Torsional Stiffness ◽  
Steel Beams ◽  
Torsional Buckling ◽  
Cold Formed Steel ◽  
Thin Walled ◽  
Flexural Torsional Buckling

In this paper the study on lateral flexural-torsional buckling of steel sigma-cross-section beams with web holes will be presented. The analysis of corresponding stability problem is based on general approach derived for a group of beams including at least mono-symmetric sections loaded transversally to their plane of symmetry. The effective flexural and torsional stiffness of steel beams with holes has been verified by tests. The results of theoretical analysis were compared with specification design procedure and also with actual behaviour of set of beams investigated by experiments. The study conclusions aim to become the background of the supplements to specified provisions for the design of steel structures.

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