Finite-element analysis and design of aluminium alloy CHSs with circular through-holes in bending

Finite-element analysis (FEA) was performed in this study on the flexural behaviour of aluminium alloy circular hollow sections (CHSs) with circular through-holes subjected to gradient and constant bending moments. The non-linear finite-element models (FEMs) were established and verified by the corresponding experimental results. The material and geometrical non-linearities, as well as the initial geometrical imperfections, were taken into account in the FEMs. The validated FEMs were employed in an extensive parametric study on a total of 408 specimens, which have the cross-section slenderness ratio (D/t) and hole size ratio (d/D) ranged from 5 to 150 and from 0.2 to 0.8, respectively. The influences of the cross-section slenderness ratio and hole size ratio of the CHSs, as well as the quantity and location of the circular through-holes on the flexural strengths of aluminium alloy CHSs with circular through-holes, were carefully evaluated. The test and FEA flexural strengths are compared with the design flexural strengths determined by the modified direct strength method (DSM) and the modified continuous strength method (CSM) developed for aluminium alloy flexural members. The comparison indicates that the current design guidelines are conservative for aluminium alloy CHSs with circular through-holes in bending. Therefore, the design equations are proposed on the basis of the modified CSM for the flexural strengths of aluminium alloy CHSs with circular through-holes. A reliability analysis was carried out to evaluate the modified DSM, the modified CSM and the proposed design equations. It is demonstrated that the proposed design equations are of high precision and reliability for aluminium alloy CHSs with circular through-holes in bending.