Modal analysis of the post-buckling behaviour of cylindrical steel panels under compression: Imperfection sensitivity and local2 interaction

This paper presents and discusses numerical results on the (i) elastic post-buckling behaviour and (ii) imperfection sensitivity of simply supported cylindrical steel panels under uniform compression. The results presented are obtained by means of a geometrically non-linear Generalised Beam Theory (GBT) formulation previously reported by the authors, which can include arbitrary member initial geometrical imperfections. The modal decomposition features of GBT enables extending the knowledge on the mechanics underlying these structural elements, which cannot be obtained with standard shell finite element analysis. The work begins by describing the GBT buckling analysis of four curved panels with distinct curvatures. Then, post-buckling results are presented and discussed for each of the four panels geometries, by considering (i) two distinct critical-mode initial geometrical imperfections shapes and (ii) five distinct amplitudes to assess the imperfection sensitivity – if the “sign” of the initial geometrical imperfection is relevant, ten amplitudes are considered. These results provide the evolution, along the equilibrium paths, of relevant modal displacement profiles, modal participation diagrams and deformed configurations. For comparison and validation purposes, shell finite element results are also reported.