中国物理B ›› 2009, Vol. 18 ›› Issue (4): 1564-1569.doi: 10.1088/1674-1056/18/4/045

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Shielding effect and emission criterion of a screw dislocation near an interfacial blunt crack

宋豪鹏, 方棋洪, 刘又文   

  1. College of Mechanics and Aerospace, Hunan University, Changsha 410082, China
  • 收稿日期:2008-07-13 修回日期:2008-10-20 出版日期:2009-04-20 发布日期:2009-04-20
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10872065 and 50801025).

Shielding effect and emission criterion of a screw dislocation near an interfacial blunt crack

Song Hao-Peng(宋豪鹏), Fang Qi-Hong(方棋洪), and Liu You-Wen(刘又文)†   

  1. College of Mechanics and Aerospace, Hunan University, Changsha 410082, China
  • Received:2008-07-13 Revised:2008-10-20 Online:2009-04-20 Published:2009-04-20
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant Nos 10872065 and 50801025).

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摘要： 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.

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.

Key words: screw dislocation, interfacial blunt crack, shielding effect, emission criterion

中图分类号:  (Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, EPR, NMR, etc.))

  • 61.72.Hh
68.35.Dv (Composition, segregation; defects and impurities) 68.35.Gy (Mechanical properties; surface strains)