Charpy impact and slow-bend tests for substandard V-notched and side-grooved specimens

Abstract

Energy correlations between standard and substandard specimens on USE and energy correlations in different stress states due to the effects of side grooving were performed with substandard Charpy specimens. In addition to impact tests slow-bend tests were conducted to study the side grooving effects on stable crack growth at the front notch tip and on triaxiality at the side notch tip by fractographs. To extract some useful engineering parameters nonlinear V-notch fracture toughness tests were also carried out for the substandard notched and side grooved specimens. Both area and volume normalizations provided good agreements on USE correlation and the geometrical correction factor (B/$B_N$) reduced the stress state effects due to the side grooving on energy correlations. Side grooves reduced the stable crack growth region and enhanced the triaxiality near the side notch tip to a brittle fracture. The values of nonlinear V-notch fracture toughness $(G_c^v)$ with 30\% side grooving had uniform values through specimen thickness from 10 mm to 5 mm for 10 mm width.