Final results of an analytical round robin exercise to support constraint effects

Scibetta, M.*; Altstadt, E.*; Callejas, R.*; Lee, B.*; Miura, Naoki*; Onizawa, Kunio ; Paffumi, E.*; Serrano, M.*; Tatar, L.*; Yin, S.*

IAEA has developed a coordinated research project (CRP) to evaluate various issues associated with the fracture toughness Master Curve for application to light-water RPVs. Topic Area 1 of the CRP is focused on the issue of test specimen geometry effects, with emphasis on determination of reference temperature T0 with the pre-cracked Charpy specimen and the bias effect. Within the analytical part, elastic plastic finite element methods are used in order to access local stress and strain information. This analytical round robin exercise has been performed by ten laboratories from nine different countries focusing on the modeling of realistic three dimensional geometries containing shallow and deep crack. Independently of the used code and of relatively small user effect differences, it is found that shallow crack specimens are more sensitive to loss of constraint than deep crack specimens for a given specimen size. The difference in terms of reference temperature between the two geometries is evaluated to be about 40C.