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2006 Research Reports
Click on the title of the research report to get the abstract, keywords and the download link for the PDF version of the report (if it is available)
Bambach M.R., Local Buckling and Post-Local Buckling Redistribution of Stresses in Slender Plates and Sections, Research Report No RR1, November 2006
Bambach M.R., Inclined Yield Lines in Flange Outstands, Research Report No RR2, November 2006
Bambach M.R.
Local Buckling and Post-Local Buckling Redistribution of Stresses in Slender Plates and Sections
Research Report No RR1, November 2006
Abstract:
Cold-formed open steel sections are comprised of component plates termed stiffened elements (webs) and unstiffened elements (flanges). The local buckling and post-local buckling behaviour of sections may be determined from the behaviour of the component plates. Much research effort has documented the theoretical elastic local buckling of plates and sections, however until recently few experimental studies have been reported on the local buckling and post-local buckling behaviour of unstiffened plates. This paper presents experimental and numerical studies of unstiffened plates and sections that contain them in both compression and bending, and in particular analyses the mechanism that provides post-buckling strength. It is shown that as with stiffened elements, the mechanism is the post-local buckling redistribution of stress, however unlike stiffened elements this redistribution can occur to such an extent that tensile stresses commonly form in axially compressed slender elements. The stress distributions at ultimate are compared with current international cold-formed steel specifications.
Keywords:
Unstiffened plates, elastic local buckling, post-local buckling, slender sections, stress redistribution
Full Research Report (pdf 554kB)
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Bambach M.R.
Inclined Yield Lines in Flange Outstands
Research Report No RR2, November 2006
Abstract:
While spatial plastic mechanism analysis has been widely and successfully applied to thin-walled steel structures to analyse the post-failure behaviour of sections and connections, there remains some contention in the literature as to the basic capacity of an inclined yield line. The simple inclined hinge commonly forms as part of the more complex spatial mechanism, which may involve a number of hinges perpendicular or inclined to the direction of thrust. In this paper some of the existing theories are compared with single inclined yield lines that form in flange outstands, by comparing the theories with plate tests of plates simply supported on three sides with the remaining (longitudinal) edge free. The existing theories do not account for different in-plane displacement gradients of the loaded edge, nor the slenderness of the plates. A modified theory is presented whereby uniform and non-uniform in-plane displacements of the loaded edge of the flange, and the slenderness of the flange, are accounted for. The modified theory is shown to compare well with the plate test data, and its application to flanges that are components of sections in compression and/or bending is presented.
Keywords:
Inclined yield lines, spatial plastic mechanisms, post-failure behaviour, plastic hinge capacity, unstiffened plates, flange outstands
Full Research Report (pdf 863kB)
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