The shielding effect and emission criterion of a screw dislocation near to an interfacial blunt crack were considered. Utilizing the conformal mapping technique, closed-form solutions were derived for complex potentials and stress fields due to a screw dislocation located near to the interfacial blunt crack. The stress intensity factor on the crack tips, and the critical stress intensity factor for dislocation emission, were also calculated. The influence of the dislocation orientation and the morphology of the blunt crack, as well as the effect of the material elastic dissimilarity upon the shielding effect and the emission criterion, were analyzed in detail. The results showed that positive screw dislocations could reduce the stress intensity factor of the interfacial blunt crack tip (shielding effect). The shielding effect increased with an increase in the shear modulus of the lower half-plane, but it decreased with an increase in the dislocation azimuth angle. The critical loads at infinity, for dislocation emission, increased with an increase in the emission angle and curvature radius of the blunt crack tip. The most probable angle for screw dislocation emission was zero. The present solutions subsumed previous results as special cases.

Shielding Effect and Emission Criterion of a Screw Dislocation near an Interfacial Blunt Crack. H.P.Song, Q.H.Fang, L.W.Liu: Chinese Physics B, 2009, 18, 1564-9