<i>R</i> Curve and Fracture Toughness of Thin Sheet Materials

Abstract

Abstract Crack growth resistance R curve tests were done on center-cracked panels of three aluminum alloys. Two methods for the measurement of crack length were compared: the compliance method and the potential method. The latter gives more consistent results. It was found that the stress intensity serves as a correlation parameter for crack growth up to a limiting value of the net section stress that is equal to 0.9 times the yield strength. The fracture stress can be accurately predicted by the R curve concept.