Specimen Geometry and Extended Crack Growth Effects on JI-R Curve Characteristics for HY-130 and ASTM A533B Steels

Publisher Website
Google Scholar
Abstract
An evaluation of the ductile fracture toughness and JIR curve properties of HY-130 and ASTM A533B-HSST-03 steels in response to systematic variations of thickness and crack length in the side-grooved compact specimen geometry was carried out. A series of 2T compact specimens was produced to varying thicknesses, and with various fatigue crack lengths. Elastic compliance JI-R curve tests were performed, and analyses ofJIc, the slope of the JIR curve, the accuracy of the Ernst-Paris-Landes approximation for JI and an assessment of the ω criterion for J-controlled crack growth were carried out. Results showed that JIc of both steels was geometry independent when validity criteria were met. Both steels displayed a clear dependence of the slope of the JI-R curve as related to thickness/ligament ratio and degree of crack extension. A limiting thickness/ ligament ratio of 1 is necessary to ensure a conservative JIR curve slope over the full range of crack growth. The Ernst-Paris-Landes expression was shown to accurately describe JI to crack extension values of 0.4 b0 for HY-130 steel. Limited evidence suggests that a minimum value of ω to guarantee J-controlled crack growth with compact specimens in HY-130 steel is 2.