GBT‐based Stability Analysis of Thin‐walled Members with Circular Axis

Abstract

This paper presents a newly developed extension of the linear Generalised Beam Theory (GBT) formulation for members with circular axis, previously developed by the authors, to the linear stability analysis case. This extension incorporates the classic GBT kinematic assumptions, which ensure efficiency without sacrificing its accuracy. The finite element implementation of the proposed formulation makes it possible to calculate bifurcation loads and associated buckling mode shapes of members with circular axis and arbitrary flat‐walled cross‐sections, undergoing global‐distortional‐local deformation, with great accuracy and computational savings (with respect to refined shell finite element models). Moreover, it is shown that the remarkable GBT modal decomposition features, stemming from the fact that the kinematic description of the beam is based on a superposition of structurally meaningful cross‐section deformation modes, enable an in‐depth insight into the nature of the buckling modes in curved members.