Acoustic emission during fracture toughness tests of SA333 Gr.6 steel

A new approach for determining initiation fracture toughness Ji has been developed based on acoustic emission (AE) and has been tested and validated on a SA333 Gr.6 steel. The Ji values thus determined are in close agreement with those obtained from both ASTM A-15 prescription and stress zone height (SZH) measurements using a constraint factor M = 4. This confirms the use of higher values of M (>2) in the blunting line equation J = MσyΔa where M is the slope of the blunting line, σy is the effective yield strength, and Δa is the crack extension.