Optimizations of parameters of a stiffened cylindrical shell

Buckling under external pressure is considered of a cylindrical shell stiffened by identical circular beams (rings) with rectangular cross section, and of an unstiffened shell with the same size of the middle surface and made of the same material. It is suggested that stiffened and unstiffened shells lose stability at the same critical pressure. Asymptotic formulas are used to obtain the critical pressure. Explicit formulas are derived for calculating approximate values of optimal parameters of a stiffened shell, which correspond to the minimum value of the ratio of the mass of a stiffened shell to the mass of an unstiffened shell. It is shown that, as the ratio of the ring width to its thickness increases, the mass ratio decreases. Optimal parameters are calculated. The results of the study can be used in the design of thin-walled structures.