Stable Postbuckling Equilibria of Axially Compressed, Elastic Circular Cylindrical Shells: A Finite-Element Analysis and Comparison With Experiments

Abstract

Postbuckling behavior of clamped circular cylindrical shells of finite length under uniform axial compression is analyzed using a potential-energy-based, displacement finite-element method. Contour maps of equal radial deflection computed from this analysis for one-tier and two-tier postbuckled, stable equilibrium patterns show very good agreement with experimentally measured contour maps for a polyester shell with L/R = 0.7 and R/h = 405. Developed for these computations, and essential for them, are: (a) A 48 DOF shell element; (b) A method to calculate accurately for the perfect shell the nonlinear fundamental path and its bifurcation points. The lowest such bifurcation point does not correspond to the first observed postbuckle pattern, which is reproduced by calculating the continuous equilibrium path from the sixth bifurcation point. Patterns of successive postbuckling shapes that are formed under additional end-shortening are determined by using a special technique to calculate equilibrium paths extending continuously from still higher bifurcation points on the fundamental path.