GBT-based buckling analysis of steel cylindrical shells under combinations of compression and external pressure

This paper reports the results of an investigation on the use of Generalised Beam Theory (GBT) to assess the buckling behaviour of steel cylindrical shells (pipes, tubes and pressure vessels) acted by combinations of axial compression and external lateral pressure. Initially, the derivation of an adequate GBT formulation is addressed  −  it (i) incorporates all the effects stemming from the presence of longitudinal and/or hoop stresses (the latter act in the circumferential direction), and (ii) takes into account the destabilising influence associated with the follower nature of the external pressure, which remains normal to the shell wall along the deformation process. Then, after numerically implementing the above formulation, by means of GBT-based beam finite elements, its application and capabilities are illustrated through the presentation and discussion of numerical results concerning the buckling behaviour of (i) pressure vessels and pipes acted by external pressure and (ii) tubes subjected to combinations of compression and external pressure. For validation purposes, most GBT results are compared with values either available in the literature or yielded by Ansys shell finite element analyses.