Rationale

ASTM E1820-25 calculates crack-tip opening displacement (CTOD) based on the formula: d=J/(ms_Y ) , where s_Y is the effective yield strength, and the factor m depends on yield strength s_YS, tensile strength s_TS, and a_0/W. Therefore, once J-integral is calculated, CTOD can also be determined if required. The current versions of Annexes A14 (Special Requirements for Rapid-Load J-Integral Fracture Toughness Testing), A15 (Normalization Data Reduction Technique), A17 (Fracture Toughness Tests at Impact Loading Rates Using Precracked Charpy-Type Specimens), and A18 (Guidelines for the Use of Direct Current Electric Potential Difference Methods for The Determination of Crack Size) only cover J-integral as fracture parameter, but there is no technical reason why CTOD shouldn’t be covered, since it can be directly derive from J. We propose here to add to the “Scope” or “Applications” sections of those four Annexes sub-sections informing the user that, once J-based fracture parameters have been obtained, CTOD-based fracture parameters also can be derived.