JIc Determination Using the Proposed Standard C-Shaped Specimen

Abstract

The proposed standard C-shaped Specimen for KIc determinations according to ASTM E399 is readily adaptable to load line deflection measurement, and thus to J-integral assessment, using procedures currently being developed for other geometries. Tests have been conducted on quenched and tempered steels to provide comparisons of JIc and KIc using both C-shaped and compact tension specimens. The effect of specimen thickness on the crack growth resistance curve and JIc has also been examined and analyzed in relation to the allowed thickness range for the proposed test method. The Merkle and Corten corrections for the C-shaped Specimen have been calculated and compared to those for other specimen geometries. J estimates based on total displacement measurements have been found to be acceptable even at short relative crack depths.