Design-by-analysis of a chemical reactor's head under sustained and thermal loads

The Direct Route approach of Design-by-Analysis of the proposed European st andard for unfired pressure vessels prEN 13445-3 is applied to a dished hea d with a concentric nozzle under the action of internal pressure and varyin g sustained and thermally induced nozzle loads. Via application of the new method, the admissibility of actions (loads) outside the shakedown range is shown. One procedure used is elastoplastic cycling and assessment of the s tructure's behaviour via the plastic strains, the other is based on Konig's theorem for progressive plastic deformation (ratcheting), using generalise d stresses and Ilyushin's approximate yield function. (C) 2000 Elsevier Sci ence Ltd. All rights reserved.