PLASTIC COLLAPSE OF THIN-WALLED RING-STIFFENED CONICAL SHELLS UNDER UNIFORM EXTERNAL-PRESSURE

Experimental tests were carried out on three thin-walled ring-stiffene d circular conical shells under uniform external pressure. Each of the se vessels suffered from two separate modes of failure: plastic, axisy mmetric collapse in the first bay, and plastic shell instability in th e middle bay. A linear finite-element analysis was carded out to compa re theoretical and experimental results in the elastic range. A thinne ss ratio was presented to determine the plastic reduction factor for t he plastic shell instability of these vessels, and this looked as if i t could be useful for design purposes.