Abstract：Abstract: The interaction between a screw dislocation and a semi-infinite wedge crack penetrating a circular inhomogeneity is investigated. Using Riemann-Schwartz's symmetry principle integrated with the analysis of singularity of complex functions, the closed form solutions of the complex potentials in both the semi-infinite matrix and the semi-circular inhomogeneity are obtained when screw dislocation located in the semi-circular inhomogeneity. The expressions of stress fields in the inhomogeneity and the force acting on dislocation are derived by using the conformal mapping technique. The shielding effect and the emission criterion of the screw dislocation are discussed in detail. The results show that positive dislocation can reduce the stress intensity factor of the wedge crack and shield the crack growth. The shielding effect decreases with the increment of dislocation azimuth angle. The critical load at infinity for dislocation emission increases with the increment of emission angle, and the most probable angle for screw dislocation emission is zero. Comparing with the case for a straight-line crack, the emission of the dislocation from a wedge crack becomes more difficult. In addition, the hard matrix can enhance the critical load for the dislocation emission.
2013, Vol. 34 
