An idealization concept for the stability analysis of ring-reinforced cylindrical shells under external pressure

A nomograph is introduced, which is based on the stability equations for an orthotropic cylindrical shell. The equations are derived from the assumption of the exact displacement versus strain relationship and of linear-elastic material behaviour. The displacement versus strain relationship is the same as Flugge indicated for the isotropic cylindrical shell. The nomograph can be used to determine in a fast and direct way the ideal local and global buckling pressure and the critical buckling form of a ring-stiffened circular cylindrical shell under external pressure. The determining values are useful for the preliminary design. They can serve as input values for an idealization concept that describes the method for obtaining a representative substructure for a finite element calculation. The subsequent geometrically and physically non-linear stability analysis of the subsystem is performed using two ring-reinforced cylinders as an example, and then compared with experimental results. (C) 2002 Elsevier Science Ltd. All rights reserved.