This paper presents the results of an investigation concerning the influence of corners with standard radii in the local buckling behaviour of thin-walled rectangular hollow section (RHS) members subjected to combinations of axial force and biaxial bending. The calculation of the half-wave length leading to the minimum critical bifurcation load is performed by means of a Generalized Beam Theory (GBT) specialization, developed taking advantage of the assumption that the stress resultants are uniform along the member length. This assumption makes it possible to obtain semi-analytical solutions, adopting half-wave sinusoidal amplitude functions for the GBT cross-section deformation modes, and leads to a numerical implementation that (i) is able to quickly solve a large number of problems and (ii) provides physical insight into the critical buckling mode mechanics, through a shell-like stress resultant-based energy criterion, as well as the modal decomposition features of the GBT semi-analytical solutions. Members with cross-sections belonging to the EN10219-2 database are analysed and their critical buckling coefficients are compared with those provided by available analytical expressions and/or currently included in steel design codes, namely Eurocode 3 and the North American Specification for Cold-Formed Steel Members. Analytical expressions are developed to take into account the (usually) beneficial influence of the rounded corners to the RHS member critical buckling stress.
- Axial force and biaxial bending combinations
- Generalized beam theory (GBT)
- Influence of rounded corners
- Local buckling
- Rectangular hollow sections (RHS)