Abstract：The shielding effect and emission criterion of a screw dislocation near an interfacial blunt crack in piezoelectric bi-materials is dealt with. Utilizing the conformal mapping technique, the closed form solutions are derived for electric displacement fields and stress fields due to a screw dislocation located near the interfacial blunt crack. The stress intensity factor and critical conditions for dislocation emission are also calculated. The influences of the position of the dislocation and morphology of the blunt crack as well as the electric-elastic properties on the shielding effect and emission criterion are discussed in detail. The results show that positive screw dislocations can reduce the stress intensity factor of the interfacial blunt crack tip (shielding effect). The shielding effect decreases with the increase of dislocation azimuth angle and the distance between the dislocation and the crack tip. The critical loads at infinity and critical remote electric displacement for dislocation emission increases with the increment of the emission angle and the curvature radius of the blunt crack tip, and the most probable angle for screw dislocation emission is zero. The present solutions contain previous results as the special cases.
2011, Vol. 32 
