Experimental study and finite element analysis on the local buckling behavior of aluminium alloy beams under concentrated loads

Abstract

This paper presents an experimental investigation on local buckling behavior of extruded 6000 series alloy I-shaped aluminium alloy beams. A total of 10 specimens with a wide range of width-to-thickness ratios (4.4–15.0 of flange, 42.9–73.1 of web) of component plates were divided into two types: one with stiffeners at mid-span, and the other without intermediate stiffeners. Failure modes, ultimate loading capacities, load-deformation responses and load-strain curves of the specimens were studied. Local buckling occurred in the top flange and web of six specimens without intermediate stiffeners, and shear local buckling occurred in the other four specimens with intermediate stiffeners though which developed a tension field. A finite element model was developed and validated against the test results, which was used for parametric analysis of 24 specimens. The investigation focused on the effects of the intermediate stiffeners and width-to-thickness ratio on the buckling strength of the aluminium alloy beams. It was found that component plates with small width-to-thickness ratios could make material function to its fullest potential; And there was a significant increase in the post-buckling strength; Eurocode 9 underestimated the loading capacity of the specimens to be safe. For the specimens with thin (width-to-thickness ratio more than 40) web, the standards should be especially enhanced. Calculation results of the finite element model consist well with the experimental results.