A number of large, historical fracture toughness data sets have been analyzed according to the provisions of ASTM E1921-22a, in order to compare two Master Curve methods for assessing potential macroscopic material inhomogeneity: simplified method and multimodal approach. Analyses conducted on 51 data sets, 20 of which inhomogeneous, demonstrated substantial equivalence between the two approaches, even below the current applicability limit of the multimodal method (20 data points). A revised (lower) limit might be considered for future revisions of the E1921 standard. Overall, the simplified method provides slightly more conservative assessments, while the multimodal approach is more accurate. Freeware tools are currently available for the application of both methodologies, and of ASTM E1921 in general, for the analysis of fracture toughness data obtained in the ductile-to-brittle transition regime.
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