Investigation of Test Method for Fracture Toughness of Borated Stainless Steel under High Strain Rate

Abstract

Image processing is used for evaluating fracture toughness of borated stainless steel (B-SUS304P-1). Displacement field around a crack tip is obtained by digital image correlation method (DIC). J-integral and crack growth increment are determined from the DIC and fracture resistance curve is derived. This method is unable to evaluate the plain strain fracture toughness, however, it is possible to investigate the influence of the strain rate on the fracture toughness. It is suggested that the influence of the strain rate on the fracture toughness of B-SUS304P-1 is small by comparing fracture resistance curves obtained by this method under various strain rate conditions.