Read Journals 1689 – Vol 68 No 1 – Optimal design of aluminium axial compression member with square hollow sections through a practical method

Aluminium columns are generally designed with hollow cross-sectional and thin-walled shapes to resist overall buckling under axial compression. Moreover, internal stiffeners are often added to column walls to improve local buckling resistance. However, only a few studies have been conducted to determine the optimal number of internal stiffeners. This study proposes a simple and practical formulation to optimally design aluminium axial compression members with internal stiffeners and assess the influence of the number of stiffeners. The objective was to minimise the weight of members to prevent the four main failure modes: yielding, overall flexural buckling, local buckling of member walls, and local buckling of internal stiffeners. The method was verified through existing experimental results from the literature. The results showed that when the number of internal stiffeners increased, the minimum weight decreased or increased by more than 20% compared to that of the columns without internal stiffeners. This indicates that there is no universal monotonicity on the number of stiffeners, and it is difficult to predict the optimal number of stiffeners using simple parameters, such as the slenderness ratio of columns and width-to-thickness ratios. Thus, the proposed optimisation method is recommended for design of aluminium compression members with internal stiffeners.