Higher buckling and lateral buckling strength of unrestrained and braced thin-walled beams: Analytical, numerical and design approach applications
Résumé
The present study investigates the flexural-torsional struts buckling and beam lateral buckling analyses. In thehighlight of braced structures, analytical solutions are derived for higher 3D buckling modes of simply supportedstruts with arbitrary cross-sections. Closed-form solutions are also investigated for lateral buckling strength ofbeams with doubly symmetric cross-sections. For more general cases, the finite element approach is adopted.In presence of torsion, warping is of primary importance. For this aim, 3D beams with 7 degrees of freedom(DOFs) per node are adopted in the analysis. The model is able to carry out higher buckling modes of barsunder compression or lateral buckling modes of beams initially in bending. The analytical and the numericalresults of the present model are compared to some available benchmark solutions of the literature and to finiteelement simulations of some commercial codes (Abaqus, Adina). The efficiency of the closed form solutions andthe numerical approach is successfully verified. Applications of higher bucklingmodes in design of braced structuresare considered according to Eurocode 3 code. A particular attention is pointed out to torsion and flexuraltorsionalbuckling modes not considered in bar strength. At the end, some solutions are proposed in order tocover the full strength of columns and beams in presence of instabilities. This proposal makes steel structuresmore performant and attractive when effects of instabilities are limited at a minimum.
Domaines
Structures
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