A SCREW DISLOCATION DIPOLE INTERACTING WITH A CIRCULAR-ARC INTERFACE CRACK

This paper investigates the problem of the elastic interaction between a screw dislocation dipole and a circular interface crack. Using the complex variable method, the closed form solutions of complex potentials and the stress fields are obtained, which is produced by the screw dislocation dipole locating in one media. The stress intensity factor at the tip of the crack, the image force and the image torque acting on the screw dislocation dipole center are also calculated. The influence of screw dislocation dipole upon stress intensity factor and the equilibrium position of the screw dislocation dipole are examined for various material property combinations and interfacial crack geometries. The results show that: 1) The screw dislocation dipole has significant shielding or anti-shielding effect on the stress intensity factor; 2) Different with the interface crack which attracts the screw dislocation dipole, the hard inhomogeneity always repels it, and the screw dislocation dipole reaches equilibrium in the neighbor of crack under some combination of them; 3) If the length of the crack or the ratio of two shear moduli reaches a critical value, the presence of the crack can change the interaction mechanism between the dipole and the interface. In addition, the influence of the crack length on the equilibrium of the dipole is significant.