Estimation of $$J{-}R$$ J - R Curves for Small-Sized COEC Specimens and Its Application Considering Crack-Tip Constraints

The normalization method has been employed to estimate the J–resistance (\(J{-}R\)) curves for C-shaped outside edge-notched compression (COEC) specimens of SA-508 steel. The COEC specimens present the lowest \(J{-}R\) curves in comparison with other three types of specimens. Based on the \(J{-}Q{-}M\) method, the constraint parameter Q determined at the mid-plane in the through-thickness direction of the specimen is used to approximately quantify the three-dimensional crack-tip constraint for COEC specimens. Combining with the previous experiments on \(J{-}R\) curves, the constraint-corrected \(J{-}R\) curves for SA-508 steel specimens are given, which may be used to predict the fracture toughness of actual cracked components in structural integrity assessment.