Search

Seven complex shaped thin-walled aluminum alloy members were tested under axial compression to investigate the local buckling and the interaction of local and global buckling behaviors. The member lengths studied were 350 mm and 190 mm, respectively. The directions of initial imperfection were in the symmetric and un-symmetric axis of the cross-section with the magnitude of 1/500 and 1/70 of the column height, respectively. Measured results included the failure modes, buckling strengths and load-axial displacement curves. A nonlinear finite element (FE) model was developed. The accuracy and reliability of the FE model was verified by experimental results. Parametric studies including 615 models consisted of different plate thickness and column heights were carried out using the validated FE model. Buckling strengths predicted by the FE model were compared with those calculated by the current design methods, including the American aluminum (AA) design manual, the European code (EC9), Chinese design specification for aluminum structures (GB 50429) and the direct strength method (DSM). Comparison results show that the cuiTent design methods underestimate the buckling strengths of complex shaped aluminum alloy members under axial compression. The buckling strengths obtained by the design codes are less than 85% of those predicted by FE model. The DSM can accurately predict the buckling strength of aluminum alloy members with complex shaped cross section under axial compression forces. Ratio between the buckling strength obtained from DSM and FE model is about 0.90. [ABSTRACT FROM AUTHOR]

Six 6063-T5 aluminum alloy tensile coupon tests were carried out and stress-strain curves obtained from tests were compared with the Ramberg-Osgood model. Comparison results show that the Ramberg-Osgood model can precisely describe mechanical properties of 6063-T5 aluminium alloy. Behaviors of ten axial compression tests on stiffened closed-section thin-walled aluminum alloy members were studied experimentally and numerically. The axial displacement, bearing capacity, lateral deflection, strain development and the failure modes of the tested specimens were recorded. All specimens failed by the interaction of local buckling and section yielding. A finite element model was presented to simulate behaviors of the tested component under axial load. The buckling strength and failure modes obtained from numerical simulation agree very well with test results. Current design codes for aluminium alloy structures, such as the American aluminum design manual (AA), the European code (BS EN1999-1-1), Chinese design specifications for aluminum structures ( GB 50429-2007), the North American specification for the design of cold-formed steel structural members (AISI) and the direct strength method (DSM), were used to calculate the buckling strength of the tested components. Comparison results show that current design codes could be applied to the design of the local buckling for stiffened closed-section thin-walled aluminum alloy columns under axial compression loads. The ratio of buckling strength predicted by DSM to the measured buckling strength is about 1.20 which indicates that the current DSM overestimates the local buckling strength for stiffened closed-section thin-walled aluminum alloy columns under axial compression loads. And a modification to the current DSM is required for the design of stiffened closed-section thin-walled aluminum alloy columns failed by local buckling. [ABSTRACT FROM AUTHOR]