Constraint dependence of the fracture toughness of reduced activation ferritic–martensitic Eurofer steel plates

The fracture behavior of a Eurofer steel plate submitted to different constraint conditions was investigated in this study. The room temperature R-curves of Eurofer plates were determined using single edge notch bend specimens and the unloading compliance method. The constraint effect was evaluated by means of specimens with different initial crack lengths and the T-stress constraint parameter was used to derive constraint modified R-curves. The comparison between experimental and predicted R-curves shows that T-stress can be effectively used to obtain constraint-modified R-curves of this type of steel, that could be used for toughness prediction under low-constraint conditions.

► The effect of the presence of shallow cracks on the J–R curves of a Eurofer plate was experimentally evaluated.
► This effect has been taken into account using the T-stress concept.
► We have used a new method proposed by Zhou to determine the T-stress based constraint-modified J–R curves.
► The results of this work have a significant practical importance in structural engineering.