Large post-buckling deformations of cylindrical shells conveying viscous flow

This paper examines the post-buckling deformations of cylindrical shells conveying viscous fluid. The wall deformation is modelled using geometrically nonlinear shell theory, and lubrication theory is used to model the fluid flow. The coupled fluid-solid problem is solved using a parallelized FEM technique. It is found that the fluid-solid interaction leads to a violent collapse of the tube such that immediate opposite-wall contact occurs after the buckling if the volume flux is kept constant during buckling. If the pressure drop through the tube is kept constant during the buckling, the fluid-solid coupling slows down the collapse (compared to buckling under a dead load). The effects of various parameters (upstream pressure, axial pre-stretch and the geometry of the tube) on the post-buckling behaviour are examined and the exact geometrically nonlinear shell theory is compared to Sanders' (1963) moderate rotation theory. Finally, the implications of the results for previous models which described the wall deformation using so called ''tube laws'' are discussed. (C) 1996 Academic Press Limited