Design of Aluminum Alloy H-Sections under Minor-Axis Bending

Much research has been reported on the global response of aluminum alloy H-sections members, while studies on the local buckling behavior of H-sections under pure bending remain relatively limited. The purpose of the research is to investigate the response of aluminum alloy H-sections subjected to minor axis bending. Using a finite element model, this study analyzed the stress distribution and failure mechanism of aluminum alloy H-sections under minor-axis bending and obtained the ultimate capacities of cross-sections covering a wide range of plate slenderness. The results were compared with the strength predictions based on EN1999-1-1 and the effective width method in AS/NZS 4600. The flange slenderness was found to play the most significant role in determining the normalized capacity. The sections are shown to exhibit an elastic-plastic stress distribution in the tensile flanges. The comparisons given in this study indicate that EN1999-1-1 underestimates the predicted bending strengths. The predictions based on the effective width method are shown to be more accurate than EN1999-1-1. An alternative design method is proposed for treating aluminum H-sections in minor axis bending. This method considers plastic stress distributions in the tensile flanges after the compressed flanges have locally buckled.