Study on the stability behavior of 7A04-T6 aluminum alloy square and rectangular hollow section columns under axial compression

To understand the stability behavior of 7A04-T6 ultra-hard aluminum alloy rectangular hollow section tubes under axial compression, 39 specimens with square and rectangular hollow sections (SHSs and RHSs, respectively) and eight to ten relative slenderness ratios were experimentally analyzed. The initial geometric imperfections were measured prior to compression tests to investigate their impact on stability capacities. The experimental results were then used to validate a finite element (FE) model, which was then used to determine the influence of relative slenderness ratio, initial imperfections, sectional height-to-width ratio, and material properties. The test and FE results were used to assess six current design standards and methods including the Chinese National Standard (GB 50429-2007), European code (EN 1999-1-1:2007), American Aluminum Design Manual (AA-2015), the Australian/New Zealand Standard (AS/NZS-1997), the Continuous Strength Method (CSM), and the Direct Strength Method (DSM). A modified design method based on AA-2015 was proposed for predicting the buckling resistance of 7A04-T6 aluminum alloy rectangular hollow tubes under axial compression and it proved to predict the results well.