The application of fracture mechanics to the notch sensitivity of graphite

A theoretical model of a doubly-notched plate of a brittle porous solid is used to investigate the effect of specimen geometry on the notch sensitivity of the material. Conformal mapping techniques are used to analyse the stress distribution in the model, which is assumed to be loaded in longitudinal shear and to fracture from a critically placed defect in the root of the notch. Results obtained from the model are compared with observed notch sensitivities of an AGL moulded graphite, both before and after irradiation, and demonstrate that, under stress conditions of this type, fracture mechanics can be used to formulate an entirely adequate failure criterion for the material. (author)