Generalised Beam Theory to Analyse the Buckling Behaviour of Aluminium or Stainless Steel Open and Closed Thin-Walled Members
This paper presents the derivation and illustrates the application of a GBT formulation, intended to analyse the buckling (bifurcation) behaviour of open and closed thin-walled members made of nonlinear elastic-plastic materials, such as stainless steel or aluminium alloys. In particular, the materially non-linear GBT recently formulated by the authors, which is valid for uniformly compressed members (columns) only, is now extended to enable handling members subjected to arbitrary end normal stress distributions not inducing pre-buckling strain reversals. Most of the attention is focused on describing and discussing the specific modifications that must be incorporated in the conventional GBT procedure. In order to illustrate the application and capabilities of the derived non-linear GBT, numerical results concerning the buckling behaviour of rectangular plates and hollow section beams (major axis bending) are presented and discussed. Some of them are also compared with values yielded by FEM analyses. The material uniaxial behaviour is modelled by means of Ramberg-Osgood stress-strain laws and both J2-deformation and J2-flow plasticity theories are implemented.