Abstract
Based on the result of Juang and Lee [J. Appl. Phys. 59, 3421 (1986)], we investigated the elastic interaction between a screw dislocation dipole and a surface crack. In addition to the image force, the image torque on the dipole is also significant. Under the action of an applied stress, the dipole is mechanically polarized with an orientation that depends on its location. The flipping energy of the dipole is also discussed. The mechanical equilibrium positions of the dipole are examined, and the regions containing these points can form a plastic zone by collecting other dipoles. The criterion of the stress intensity factor for generating dipoles is identified. In addition, a comparison between monopole and dipole interactions with a surface crack has been accomplished. Finally, this solution can be reduced to three special cases.