Abstract Shielding effect and emission criterion of a screw dislocation near an interfacial blunt crack are dealt with in this paper. Utilizing the conformal mapping technique, the closed-form solutions are derived for complex potentials and stress fields due to a screw dislocation located near the interfacial blunt crack. The stress intensity factor on the crack tips and the critical stress intensity factor for dislocation emission are also calculated. The influence of the orientation of the dislocation and the morphology of the blunt crack as well as the material elastic dissimilarity on the shielding effect and the emission criterion is discussed in detail. The results show that positive screw dislocations can reduce the stress intensity factor of the interfacial blunt crack tip (shielding effect). The shielding effect increases with the increase of the shear modulus of the lower half-plane, but it decreases with the increase of the dislocation azimuth angle. The critical loads at infinity for dislocation emission increases with the increase of emission angle and curvature radius of blunt crack tip, and the most probable angle for screw dislocation emission is zero. The present solutions contain previous results as special cases.
Received: 13 July 2008
Revised: 20 October 2008
Accepted manuscript online:
PACS:
61.72.Hh
(Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.))
Fund: Project supported by the National
Natural Science Foundation of China (Grant Nos 10872065 and
50801025).
Cite this article:
Song Hao-Peng(宋豪鹏), Fang Qi-Hong(方棋洪), and Liu You-Wen(刘又文) Shielding effect and emission criterion of a screw dislocation near an interfacial blunt crack 2009 Chin. Phys. B 18 1564
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