Experimental and numerical study of aluminium alloy angle-section stub columns

This paper reports experimental and numerical studies on the behaviour and compression resistances of aluminium alloy angle-section stub columns. A testing programme was firstly carried out, including material coupon tests and stub column tests. Both equal-leg and unequal-leg angle-sections were considered in the testing programme. The member lengths of the angle-section stub column specimens were selected based on a preliminary elastic buckling analysis prior to testing, in which their predominant failure buckling mode was analytically found to be torsional buckling. The torsional buckling failure mode was also clearly observed in the testing programme, indicating that angle-section stub columns exhibit different failure mode from their hollow-section and T-section counterparts that are susceptible to local buckling. Upon completion of the testing programme, a numerical modelling programme was conducted, where finite-element models were developed and validated against the test results. The validated models were then adopted to conduct parametric studies to generate more numerical data. The obtained test and numerical data were used to perform a design analysis, where the relevant design rules in the European, American, Australian/New Zealand and Chinese standards were evaluated. The analysis results indicate that both the European and Australian/New Zealand standards result in conservative resistance predictions for angle-section stub columns with low and high torsional slendernesses. Meanwhile, they offer unsafe resistance predictions for some angle-section stub columns with intermediate torsional slendernesses. In contrast, the American and Chinese standards yield a high level of design conservatism over the full range of torsional slendernesses.