An engineering methodology for constraint corrections of elastic–plastic fracture toughness – Part I: A review on probabilistic models and exploration of plastic strain effects

•Extensive survey of the considerable work in statistical modeling of cleavage fracture.•Development of limiting distributions for fracture stress including plastic strain effects.•Introduction of a modified Weibull stress incorporating plastic strain effects.•Fracture resistance depends on the adopted plastic strain model.•Inclusion of plastic strain effects reduces constraint corrections in toughness predictions.

This work describes a micromechanics methodology based upon a local criterion incorporating the effects of plastic strain on cleavage fracture coupled with statistics of microcracks. A parameter analysis is conducted under well-contained plasticity, where near-tip fields with varying constraint levels are generated through a modified boundary layer formulation. These analyses are extended to assess the effects of plastic strain on fracture toughness correlations for conventional SE(B) specimens with varying a/Wa/W-ratios. Fracture toughness predictions for a pressure vessel steel tested in the DBT transition region based on the proposed methodology are considered in Part II of this article.