NONLINEAR LOWER BOUNDS FOR SHELL BUCKLING DESIGN

Based on rigorous parametric non-linear elastic buckling analyses, the present work underlines the developments towards theoretical lower bounds of existing experimental buckling loads for some of the most practical shell geometries and loading cases, namely circular cylindrical shells under external pressure and/or axial loads and spherical caps under external pressure. Simple equations and formulae are presented and their predictions for buckling loads are compared with available test results and values prescribed by some of the existing design codes. These explicit lower bounds are close and non-conservative estimates of buckling lends of imperfect shells and as such are proposed as a consistent and rational basis for design of these shell structures.