GBT formulation to analyse the first-order and buckling behaviour of thin-walled members with arbitrary cross-sections

This paper presents the derivation, validation and illustration of a generalised beam theory (GBT) formulation intended to perform first-order and buckling analyses of arbitrary thin-walled members, namely members with cross-sections that combine closed cells with open branches. Following a brief overview of the so-called “conventional GBT formulation”, as well as of the available extensions for different specific cross-section types, the paper addresses in detail the modifications that must be incorporated into the GBT cross-section analysis procedure to handle the simultaneous presence of closed cells and open branches. The proposed formulation is then employed to analyse the first-order and buckling behaviours of thin-walled members (mostly beams) with complex cross-sections. For validation purposes, the GBT-based numerical results are compared with values yielded by shell finite element and finite strip analyses.