Recent Developments to Improve Crack Opening Areas for R6 Leak-Before-Break Procedures

Autor: R. Charles, D. G. Hooton, P. J. Budden, H. Dodia, John Sharples
Rok vydání: 2008
Předmět:
Zdroj: Volume 6: Materials and Fabrication, Parts A and B.
DOI: 10.1115/pvp2008-61064
Popis: This paper provides an overview of developments that have been undertaken in recent years in order to extend the Crack Opening Area (COA) solutions for Leak-Before-Break (LBB) within the R6 Flaw Evaluation Procedures. For high temperature operations, the effect of creep strains on COA has been studied using finite element (FE) models of a centre-cracked plate with combined primary and secondary stresses. Primary creep, as well as secondary creep, has been included in the studies. The ultimate aim of this work is to further develop and validate by FE analysis, simplified expressions for the prediction of COA under realistic loading conditions for high temperature operations. For COA evaluations in general, work has been undertaken by FE modelling of the following aspects: • Straight-fronted cracks under combined loading. • Converging/diverging cracks whereby the length on one surface is different to that on the other surface (i.e. cases where there is a through-wall variation in crack length). • Weld strength mis-match effects. • Component features effects.Copyright © 2008 by ASME
Databáze: OpenAIRE