Prediction of Cleavage Fracture Probability for Ferritic Steels in the Transition Region

A method is described for modelling the stochastic variability of toughness data for ferritic steels in the brittle to ductile transition regime. The present model is based on two ingredients: a weakest link approach using Weibull statistics with a suitable modification to include the effect of ductile tearing, and an accurate expression of the material J-R curve, determined from fractography. The model provides a rationale for the different fracture behaviour of a material over the whole range of temperature, from fully stable J-R behaviour at high temperature down to brittle fracture under LEFM conditions at low temperature.