Numerical schemes for defining reference stress in components containing defects

In R6 and R5, the standards of integrity assessments of components containi ng defects established by the former Central Electricity Generating Board ( CEGB) in the UK, the basic procedure in calculating the crack driving force parameters, J-integration and C*-integration is to define the reference st ress, sigma(ref), on the defective section. Three methods of directly defin ing the reference stress, sigma(ref) [multiple steady-state creep analysis (MSCA) method, creep module-modified iteration (CMMI) method and elastic mo dule-modified iteration (EMMI) method], are suggested in this paper, differ ing from the common methods in which the limit loads of the components are first calculated and then the sigma(ref) is convertibly determined. The bas ic conceptions and calculational steps of these methods are discussed and c ompared in the context, and the validity is demonstrated by several example s. (C) 1999 Elsevier Science Ltd. All rights reserved.