The behaviour of locally-supported cylindrical shells: unstiffened shells

Many metal silos and tanks are locally supported on columns or other discre te supports to permit easy access beneath the vessel. The discrete supports introduce local forces into the cylindrical shell, which in turn produces zones of local high axial compression. The strength of compressed cylindric al shells has long been known to be governed by buckling considerations, bu t the buckling strength of discretely supported cylinders has only been inv estigated in recent years. Design rules which pre-date this study were empi rical in nature and not based on rigorous buckling calculations or tests. I n the present study, the theoretical buckling behaviour in the elastic-plas tic range has been found to be so complicated that much work is needed to d efine the buckling strength for the purposes of structural design. This pap er presents a description of the linear and nonlinear behaviour of isotropi c unstiffened cylinders which are discretely supported at the lower edge. M uch of the information given here is vital to the development of a more rel iable design rule for shells under these loading conditions. (C) 2000 Elsev ier Science Ltd. All rights reserved.