Comparison of elastic interaction of a dislocation and a crack for four bonding conditions of the crack plane

A comparison of elastic interaction of a dislocation and a crack for four b onding conditions of the crack plane was made. Four cases of single crystal line material, sliding grain boundary, perfectly bonded interface, and slid ing interface were considered. The stress intensity factors arising from ed ge and screw dislocations and their image forces for the above four cases w ere compared. The stress intensity factor at a crack tip along the perfectl y bonded interface arising from screw dislocation can be obtained from that in a single crystalline material if the shear modulus in the single crysta lline material is replaced by the harmonic mean of both shear moduli in the bimaterial. The stress intensity factor at a crack tip along the sliding i nterface arising from edge dislocation in the bimaterial can be obtained fr om that along the sliding grain boundary in the single material if the mu/( 1 - v) in the single material is substituted by the harmonic mean of mu/(1 - v) in the bimaterial where mu and v are the shear modulus and Poisson's r atio, respectively. The solutions of screw dislocation near a crack along t he sliding grain boundary and sliding interface are the same as that of scr ew dislocation and its mirror image. Generally, the effect of edge dislocat ion for perfectly bonded interface on the crack propagation is mon pronounc ed than that for the sliding interface. The effect of edge dislocation on t he crack propagation is mixed mode for the cases of perfectly bonded interf ace and single crystalline material, but mode I fracture for the cases of s liding interface and sliding grain boundary. All curves of F-x versus dista nce u from the dislocation at interface to the right-hand crack tip are sim ilar to one another regardless of dislocation source for both sliding inter face and perfectly bonded interface. The level of F-x for m = 0 is larger t han that for m = -1.