Abstract
By using a dislocation model for the surface crack and images for the free surface, the interactions between coplanar screw dislocations and a surface crack are analyzed. For the case of one dislocation, the dislocation distributions in the crack, the total Burgers vector, and the stress intensity factor due to the dislocation are compared with two other models involving finite cracks. Although they have the same zero order pertaining to the situation of a semiinfinite crack, the high-order terms are all different. For the case of two or more dislocations, the present model has the capability of separating all the interaction term so that Newton's third law of interaction between dislocations is preserved. © 1985.