Stress analysis on a Zener crack nucleation from an eccentric wedge disclination in a cylinder

• Published in: International journal of engineering science 2009-09, Vol.47 (9), p.811-820
• Main Authors: Luo, J., Xiao, Z.M., Zhou, K.
• Format: Article
• Language: English
• Subjects: Condensed matter: structure, mechanical and thermal properties; Crack nucleation; Critical disclination power; Defects and impurities in crystals; microstructure; Disclination; Equilibrium crack length; Exact sciences and technology; Fracture mechanics (crack, fatigue, damage...); Fundamental areas of phenomenology (including applications); Linear defects: dislocations, disclinations; Physics; Solid mechanics; Stress relaxation; Structural and continuum mechanics; Structure of solids and liquids; crystallography; Zener crack
• ISSN: 0020-7225; 1879-2197
• DOI: 10.1016/j.ijengsci.2009.05.006

The stress relaxation of an eccentric (off-center) negative wedge disclination in an isotropic homogeneous cylinder by nucleation of a Zener crack has been investigated with a continuum model. The nucleated Zener crack is simulated with distributed edge dislocations. The stress intensity factor (SIF) at the sharp tip of the Zener crack is computed through solving the singular integral equations formulated. By enforcing the fracture criterion at the sharp tip, the critical disclination power to nucleate a Zener crack is determined. The equilibrium crack lengths of the crack are then calculated when the disclination power is above the critical value. It is found that there is a special position at which the critical disclination power reaches the minimum value. As the disclination deviates from this position, the critical disclination power increases. Two or four equilibrium crack lengths could be found for the Zener crack, dependent upon the power and off-center position of the disclination. The influence of the off-center distance on the equilibrium crack lengths and the dependence of the critical disclination power and stable equilibrium crack lengths on cylinder radius are also discussed.