Buckling Of I-beams Research Articles

Elastic lateral-distortional buckling of I-beams and the Meck Plot

Meck Plot is an adapted version of the well-known Southwell method to the case of lateral-torsional buckling, which indeed reflects the physical inter-dependence of lateral flexure (lateral displacement) and torsion (rotation) in the structure. In the recent reported studies, it has been shown experimentally and theoretically that lateral displacement of an I-beam undergoing elastic lateral-distortional mode of buckling is interestingly directly coupled with other various deformation characteristics such as web transverse strain, web longitudinal strain, vertical deflection, and angles of twist of top and bottom flanges, and consequently good results have been obtained as a result of application of the Meck`s method on lateral displacement together with each of the aforementioned deformation variables. In this paper, it is demonstrated that even web transverse and longitudinal strains, vertical deflection, and angles of twist of top and bottom flanges of an I-beam undergoing elastic lateral-distortional buckling are two-by-two directly coupled and the application of the Meck Plot on each pair of these deformation variables may still yield reliable predictions for the critical buckling load.

Discussion of “Experiments on Distortional Buckling of I-Beams” by Tadeh Zirakian and Hossein Showkati

Discussion of “Experiments on Distortional Buckling of I-Beams” by Tadeh Zirakian and Hossein Showkati

Degradation and Buckling of I-Beams under Cyclic Pure Bending

This paper presents experimental and numerical results of the elasticplastic response and buckling of S3 x 5.7 steel and aluminum I-beams subjected to cyclic pure bending. A special 4-point bending device was designed and built for this purpose. The emphasis of the work is on the description of the response and buckling of the beams. The numerical results were obtained using a commercial finite element program that implements the nonlinear kinematic hardening plasticity model. Results indicate that the beams considered, most of which had length-to-height ratio of 5, buckled first in a global mode involving either twisting or lateral deflections of the beams. The prevailing deflection mode seems to be determined by the nature of the initial geometric imperfections. The deformations induced by the global deflections could induce a local buckle at mid-span. The finite element predictions yield results that qualitatively reproduce the development of most of the aspects of the response of the beams, but generally at a slower rate.

Distortional Buckling of I-Beams by Finite Element Method

Distortional buckling, unlike the usual lateral-torsional buckling in which the cross-section remains rigid in its own plane, involves distortion of web in the cross-section. This type of buckling typically occurs in beams with slender web and stocky flanges. Most of the published studies assume the web to deform with a cubic shape function. As this assumption may limit the accuracy of the results, a fifth order polynomial is chosen here for the web displacements. The general line-type finite element model used here has two nodes and a maximum of twelve degrees of freedom per node. The model not only can predict the correct coupled mode but also is capable of handling the local buckling of the web.

Elastic, Lateral‐Torsional Stability of Beams: General Considerations

The paper presents a more accurate solution for the elastic, lateral-torsional buckling of I-beams under unequal end moments which incorporates accurately the effects of moment gradient, lateral end restraint, and beam slenderness. Since lateral-torsional buckling involves warping and torsional modes of deformation, the proposed approach treats the problem as the superposition of two hypothetical cases of beam buckling corresponding to zero warping and zero torsional rigidity. The effects of moment gradient and lateral end restraints are considered independently on each mode and then superimposed to obtain the critical moment of the combined mode. The proposed analytical model is used to derive new parametric expressions for moment modification and effective length factors as design aids.

Inelastic local buckling of fabricated I-beams

Abstract A finite strip method of analysis is presented for the inelastic local buckling of I-beams fabricated by welding. Stiffness and stability matrices for the section are developed at a monotonically increasing load factor, and the critical moment is that for which the buckling determinant vanishes. Critical moments determined in this way are shown to agree well with test results. The limiting depth-to-thickness ratios for the web which correspond to compact and semi-compact sections are investigated, and it is shown that the values given in BS 5950: Part I are unconservative for an extensive range of section geometries. Based on a parametric study, alternative and more accurate formulations for the critical web slendernesses are proposed.

Lateral Buckling of I-Beams Subjected to Unequal End Moments

Experimental investigation into elastic and inelastic lateral buckling of aluminum alloy I-beams subjected to unequal end moments; approximate method for determining inelastic buckling strength of I-beams with this type of loading; suggestions by which nonuniform bending could be handled more accurately in present design specifications.