A GBT-based finite element for the buckling analysis of thin-walled members with circular axis

This paper presents a GBT-based (beam) finite element for performing buckling (bifurcation) analyses of thin-walled members with circular axis. The bifurcation eigenvalue problem is obtained from the non-linear equilibrium equations, using the linear stability analysis concept, while incorporating the classic GBT kinematic assumptions, which are essential to obtain significant computational savings with respect to shell finite element models. The accuracy and efficiency of the proposed finite element is assessed in several numerical examples involving complex global-distortional-local buckling. It is shown that (i) the proposed element leads to results that match accurately those obtained with refined shell finite element models, but with much less DOFs, and (ii) the GBT modal decomposition features provide an in-depth insight into the nature of the buckling modes in curved members.