THE STEREOPHOTOGRAMMETRIC DETERMINATION OF THE PLASTIC WORK FOR DUCTILE FRACTURE

摘要

By analyzing stereoscopic scanning electron micrographs with a system for automatic image processing the topography of fracture surfaces is reconstructed. The misfit between two opposite fracture surfaces after failure can be measured. After the reconstruction procedure several fractographic quantities like the critical crack tip opening displacement (CODi) and angle (CTOA) can be determined. With the knowledge of COD, CTOA and the surface misfit the amount of plastic energy necessary for crack initiation and shaping the fracture surface can be estimated. These calculated values are compared with experimentally obtained global crack growth resistance curves in terms of the J-integral and the energy dissipation rate.