A study to estimate crack length using the separability parameter Spb in steels

The separability property with Spb parameter was used in this work to estimate the instantaneous crack length in pre-cracked specimens. A test matrix, pre-cracked ASTM C(T), SE(B) specimens and non-standard A(B) arc-shaped geometry was prepared. Materials were ASTM 387-Gr.22 2.25Cr–1.0Mo steel, an API Gr.N80 and HSLA welded joints. Initial and final crack lengths were measured on the crack surface and instantaneous crack length was determined by the compliance method to compare against the values of crack length estimated using the Spb parameter. The difference between the resulting values was less than 15%Δa suggested as reference in ASTM E1820-96.