042 Brittle Failure of Inclined Key-hole Notches in Isostatic Graphite under in-Plane Mixed Mode Loading

Brittle fracture of isostatic graphite is studied experimentally and theoretically using plates containing key-hole notches subjected to different degrees of loading mixity. The main purpose of this paper is twofold. First, to provide a new set of experimental results on fracture of notched graphite samples, with different values of loading mixity and notch radii, which may be helpful for researchers because enlarges the very scarce available data; and second, to provide a fracture criterion for polycrystalline graphite under the above mentioned conditions. The averaged value of the strain energy density over a well-defined volume is used to predict the static strength of the considered specimens. Good agreement is found between the experimental data for the critical loads to failure and the theoretical predictions based on the constancy of the mean strain energy density over the material volume.