Approximate Analysis of the Plastic Limit Pressures of Nozzles in Cylindrical Shells

An estimate of the limit pressure for cylindrical nozzles in cylindrical shells is derived from an upper bound analysis based on an assumed velocity distribution. The analysis is restricted to nozzle/shell diameter ratios of 1/2 or less. Comparisons with other theoretical approaches and the results of a single experiment are shown. Design graphs based on the analysis have been prepared to indicate the amount of nozzle or shell thickening required to make the limit pressure of the nozzle-cylinder structure approximately equal to the yield pressure of the imperforated cylinder.