The interaction between a screw dislocation and an interfacial cruciform crack and collinear linear cracks

Abstract

The interaction between a screw dislocation and an interfacial cruciform crack and collinear linear cracks under loads at infinity was investigated. General solutions of complex potentials to this problem were derived by using complex potential theory. As illustrative examples, the closed form solution for a screw dislocation interacting with an interfacial cruciform crack and a linear crack is obtained. The stress intensity factor and critical stress intensity factor for dislocation emission are also calculated. The results show that the shielding effect increases with the increase of the shear modulus and the distance between the two cracks, but it decreases with the increase of dislocation azimuth and the distance between the dislocation and the cruciform crack tip. The critical loads at infinity for dislocation emission increase with the increment of the emission angle, the distance the two cracks and the vertical length of the cruciform crack.

Keywords:

• screw dislocation
• interfacial cruciform crack
• dislocation emission criterion

Acknowledgements

The authors would like to thank the support by the National Natural Science Foundation of China under Grant NNSFC 10872065 and 50801025, and Hunan Provincial Innovation Foundation for Postgraduates CX2009B067.