A Methodology for Ductile Fracture Analysis Based on Damage Mechanics: An Illustration of a Local Approach of Fracture

Abstract

Major solutions needed in fracture analysis are (a) simple and accurate material characterization and (b) easy transferring of material data to cracked structures. In the proposed methodology, constitutive relationships, including cavity growth and coalescence, are used. Material characterization is based on the simple notched tension test. Several structural steels have been characterized, especially A508 steel, and the direct transferring of material data has been demonstrated with tests on circumferentially cracked tension specimens. In addition, the extrapolation of material data to different inclusion contents and temperatures was attempted, with favorable results for the first factor through a specific parameter of the model. The temperature dependence of A508 steel ductility is related to an inverse strain rate effect on the flow curve; the modeling of this effect gives encouraging results, but it must be refined to produce an effective prediction.