Application of Elastic-Plastic Finite Element Analysis to Determine the Ultimate Load of Components

An assessment of pressure retaining components based on ultimate load (or plastic instability load) is used in Section VIII Div. 2 and Section III Appendix F of the ASME Boiler and Pressure Vessel Code, as well as in various fitness-for-service standards and guidelines. The ultimate load analysis strives for a realistic prediction of the plastic behavior of a component up to the highest load or load combination that the component can support. The high level of applied load may cause significant deformations in the component, and for an accurate assessment the analysis must consider the effect of these deformations on the material as well as on equilibrium and the state of stress. This paper discusses briefly the basis of ultimate load analysis and considerations in performing such analysis with finite element analysis. The main focus is to validate the analysis approach by demonstrating close agreement between finite element analysis and analytical solutions and the results of component tests.Copyright © 2015 by ASME