Elastic behavior of dislocation dipoles near a blunt crack

Using the conformal mapping method, the elastic interaction between a screw dislocation dipole and an interfacial crack emanating from a semi-elliptic hole is investigated. We have derived the complex potential and stress field. Form the stress field, the stress intensity factor, crack extension force, strain energy, image force and image torque on the dipole are obtained. Besides the translation of the dipole caused by the image force on the dipole center, an image torque acting upon the dipole center is also crucial. Both the translation and rotation must be considered in the static equilibrium. The stress intensity factor at the crack tip is strongly influenced by both the dipole orientation and the angle of the dipole center. In addition, when the crack is blunt, the stress intensity factor at the crack tip is reduced.