A comparison of brittle and ductile behaviour of cracks inside a circular inclusion

The brittle and ductile behaviour of a shear crack situated at the centre or at the interface inside a circular inclusion is analyzed. The shear crack in antiplane strain mode is treated as a double pile-up of screw dislocations. The plastic relaxation of the shear crack is analyzed by representing the plastic zone by giant screw dislocations. A critical RDC criterion is used to determine the tendency of the shear crack to extend in a brittle manner across the inclusion. Comparison is made on the behaviour of the plastic zone at the tip of both the cracks. Conclusions are made on the fracture behaviour of a circular inclusion situated in an infinite matrix. © 1975.