Numerical investigation and design of aluminum alloy circular hollow section columns

This paper presents a numerical investigation of aluminum alloy circular hollow section non-welded and welded columns using finite element analysis. A non-linear finite element model was developed and verified against fixed-ended column tests. The column specimens were extruded from heat-treated aluminum alloys of 6063-T5 and 6061-T6, and the ends of the columns were transversely welded to aluminum end plates for the welded columns. The non-welded columns without welding of end plates were also investigated. The welded columns were modeled by dividing the column into different portions along the column length, so that the heat-affected zone softening at both ends of the welded columns was included in the simulation. The initial local geometric imperfections of the columns were measured in this study. Geometric and material non-linearities were incorporated in the finite element model. The verified finite element model was used for a parametric study of fixed-ended aluminum alloy circular hollow section columns. A comparison of the column strengths predicted by the finite element analysis and the design strengths calculated using the current American, Australian/New Zealand and European specifications for aluminum structures was presented. The column strengths were also compared with the design strengths predicted by the direct strength method, which was developed for cold-formed carbon steel members. Design rules were proposed for aluminum alloy circular hollow section columns with transverse welds at the ends of the columns. Reliability analysis was performed to evaluate the reliability of the design rules.