GENERAL INSTABILITY OF SWEDGE-STIFFENED CIRCULAR-CYLINDERS UNDER UNIFORM EXTERNAL-PRESSURE

A theoretical and experimental investigation into the general instability of nine swedge-stiffened circular cylinders under uniform external pressure is described. The investigation found that most of the vessels suffered plastic general instability, and that initial out-of-roundness played a significant role in the magnitude of the elastic knockdown. The theoretical analysis was based on the finite-element method, and a thinness ratio is proposed from which one can determine a plastic reduction factor when more experimental results are available.