Investigation of the Stresses and Interaction Effects of Nozzle-Cylinder Intersections When Subject to Multiple External Loads

Analyzing and solving the problem of practical cylinder-cylinder pressure vessel intersections is challenging when using a finite element approach. Although numerous theoretical and finite element solutions have been developed for the cylinder-cylinder intersection problem, there remains the requirement for an updated, innovative model which takes account of all practical as-fabricated features including fillets and crotch corner ground radii. This study presents the development of a suitable model, based on the results of a parametric macro study, which is able to compare all of these operations on a single, high fidelity model. This study considers a cylindrical pressure vessel with a single nozzle connection without reinforcement plate and examines the maximum stress values in the nozzle-shell intersection area (crotch corner) under the various loads applied to the nozzle. Additionally, internal pressure and external load actions on the nozzle, including effects of circumferential, torsional, and longitudinal moments are compared using a suitable finite element approach. Furthermore, equations and solutions for external loads in spherical and cylindrical shells are given in WRC Bulletins 107 and 537. Therefore, comparisons with the results obtained from these are made for validation purposes and the overall impact of the new as-built approach is presented.