Bz. Margolin et al., PROBABILISTIC MODEL FOR FRACTURE-TOUGHNESS PREDICTION BASED ON THE NEW LOCAL FRACTURE CRITERIA, International journal of pressure vessels and piping, 75(4), 1998, pp. 307-320
The stochastic nature of various critical parameters controlling cleav
age fracture of nuclear pressure vessel steels has been analysed. On t
he basis of the performed analysis the local criterion for cleavage fr
acture proposed by authors [1,2] has been modified into a probabilisti
c statement. The probabilistic model for fracture toughness prediction
has been elaborated on the basis of the modified local criterion for
cleavage fracture, the ductile fracture criterion proposed by authors
earlier and the approximated solution for problems relating to the str
ess-strain state near the crack tip. This probabilistic model allows o
ne to predict the dependence of K-IC on temperature for any given prob
ability of brittle fracture; to describe the effect of the specimen th
ickness on K-IC; and to determine the scatter band for the brittle to
ductile transition temperature. The connection of parameters determini
ng the scatter of K-IC with material properties has been analysed. Com
parison of experimental and calculated results has been performed as a
pplied to a 2.5Cr-Mo-V nuclear pressure vessel steel. The proposed pro
babilistic model has been shown to describe the lower and upper envelo
pes for a large number of experimental data. (C) 1998 Elsevier Science
Ltd. All rights reserved.