Axial compression behaviour of 7A04-T6 high-strength aluminium alloy SHS and RHS stub columns

Abstract

The axial compression behaviour of extruded 7A04-T6 high-strength aluminium alloy square and rectangular hollow section (SHS/RHS) stub columns were presented in this paper. Seven SHS and seven RHS stub columns, including Class 2, 3 and 4 cross-sections, were tested under axial compression. The material properties, failure modes, axial load-end shortening curves and ultimate resistances were analysed. The finite element (FE) models were then developed and verified against the experimental results, and followed by parametric studies with 312 cross-sections to generate a broad numerical data. The obtained test and FE results were utilised to assess the current design provisions as set out in European, Chinese, American and Australian/New Zealand standards. The results revealed that the four standards generally yielded unsafe predictions for the local buckling resistances and conservative results for cross-section yielding resistances of 7A04-T6 high-strength aluminium alloy SHS and RHS stub columns. Modifications to the Chinese standard and the revised direct strength method (DSM) were respectively proposed which were shown to provide more accurate and consistent predictions. The reliability analysis was performed to confirm that both of the suggested design methods met the reliability requirements.