Experimental investigation and numerical analysis of pin-ended extruded aluminium alloy unequal angle columns

The structural performance of aluminium alloy unequal angle columns was investigated in this study. Fourteen columns made of two extruded aluminium alloy unequal angle cross-sections were tested. Complementary material property tests and geometric imperfection measurements were also carried out. The test setup, procedure and results were fully reported. After the tests, numerical models were developed to replicate the tested pin-ended extruded aluminium alloy unequal angle column behaviour. The validated finite element models were then adopted to analyse the effect of the configuration of initial geometric imperfections, which proved to be pivotal in mode interaction of the column buckling performance. Parametric studies were carried out with specific initial imperfection configuration to generate further numerical data. The ultimate resistances derived from the experiments and finite element analyses were employed to evaluate the applicability of the current codified standards. The result comparison shows that current design provisions yield unsafe predictions for pin-ended unequal angle columns since the buckling mode interaction is not considered. The development of applicable design proposals and further investigation into buckling modal participation for pin-ended extruded aluminium alloy unequal angle columns are required.