Elastic shakedown in pressure vessel components under proportional and non-proportional loading

Abstract

This paper presents methods, based on inelastic finite element analyses, to estimate the elastic shakedown load for a structure subjected to proportional or non-proportional loading. One of the methods (for proportional loading) is based on Melan's elastic shakedown theorem while the other (for non-proportional loading) is based on Polizzotto's extended shakedown theorem. The methods, called non-linear superposition methods, are used to investigate the shakedown behaviour of thick cylinders with cross bores and that of a nozzle/cylinder intersection. The methods are well suited to be used as a shakedown calculation tool in the new European oode BS EN 13445-3 'Unfired pressure vessels' Annex B to demonstrate elastic shakedown.