On the effect of sampling volume on the microscopic cleavage fracture stress

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journal

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Original languageEnglish
Pages (from-to)697-703
Journal / PublicationEngineering Fracture Mechanics
Issue number6
Publication statusPublished - 1988
Externally publishedYes


Reported observations of an experimental variation in the microscopic fracture stress for transgranular cleavage (σ*f) with specimen geometry and size are quantitatively examined in terms of a weakest-link statistical model for brittle fracture, wherein failure coincides with the critical propagation of a particle microcrack into the matrix. By analysing the onset of fracture in the 'sharp-crack' (KIc) specimen, the 'rounded-notch' (Charpy) specimen, and the uniaxial tensile specimen, it is shown that values of σ*f are reduced progressively in the 'sharp-crack', notched and unnotched geometries and with increasing specimen size, consistent with an increase in statistical sampling volume. Quantitative predictions for the magnitude of this variation are given for a low strength steel.