Measurement of ductile crack extension in single edge notch tensile specimens

The determination of ductile tearing resistance has since long been focused on high constraint single edge notch bend and compact tension specimens. However, several structures, such as pipelines, have a significantly lower constraint level. To minimize the conservatism involved in the assessment of defects in these structures, nowadays focus is put on the evaluation of tearing resistance using low constraint, single edge notched tension (SENT), specimens. This work compares two measurement techniques for the evaluation of ductile crack extension in such specimens. It is observed that both the unloading compliance and the direct current potential drop technique allow an accurate measurement. However, the calibration of the potential drop technique is more straightforward as it relies on the use of an analytical expression instead of advanced 3D elastic-plastic finite element simulations, as is the case for the unloading compliance technique