Buckling Under External Pressure of Cylindrical Shells Evenly Stiffened by Rings Only

Calculations are given for determining the critical pressure for panel buckling as well as general instability of shells evenly stiffened by rings with equal spacings. The panel buckling stress is calculated by determining the length of the equivalent simply supported shell, taking account of the rotational restraints offered by the rings. The limited applicability of small deflection theory is accounted for by partially neglecting the curvature of short shells. Rotational spring constants are calculated for rings with plate and box sections. Critical pressures from general instability are calculated by the method of split rigidities. Reduction factors for plasticity and eccentricity are discussed. An example of the calculation is given and is compared with the experimental result.