Abstract
The elastic interaction between screw dislocation and collinear internal and surface cracks has been investigated by the dislocation modelling method. The dislocation distribution function to simulate the cracks, the stress field and the stress intensity factor at the crack tip are obtained. From the stress field, we have derived the force on the dislocation, the zero-force position and the critical stress intensity factor for dislocation emitted from the crack tip. The critical stress intensity factor for dislocation emitted from the crack tip is affected by the other crack. The dislocations inside the crack also play an important role in fracture. Finally, four special cases can be obtained from our results: 1. (1) the interaction between a dislocation and a surface crack; 2. (2) the interaction between a dislocation and an internal crack; 3. (3) the interaction between two dislocations with a surface crack; 4. (4) the interaction between a dislocation and an internal crack near a free surface. © 1991.