Interaction between a cycloid wavy surface and a screw dislocation in a piezoelectric material

2021 ◽  
Author(s):  
Xu Wang ◽  
Peter Schiavone
Keyword(s):  
Screw Dislocation ◽  
Piezoelectric Material ◽  
Wavy Surface

Interaction Between a Semi-Infinite Crack and a Screw Dislocation in a Piezoelectric Material

1999 ◽  
Vol 67 (1) ◽  
pp. 165-170 ◽  
Author(s):  
Kang Yong Lee ◽  
Won Gyu Lee ◽  
Y. Eugene Pak
Keyword(s):  
Screw Dislocation ◽  
Piezoelectric Material ◽  
Electric Displacement ◽  
Crack Tip ◽  
Linear Elasticity Theory ◽  
The Core ◽  
Line Charge ◽  
Extension Force ◽  
Line Force ◽  
Field Intensity Factors

The interaction between a semi-infinite crack and a screw dislocation under antiplane mechanical and in-plane electrical loading in a linear piezoelectric material is studied in the framework of linear elasticity theory. A straight dislocation with the Burgers vector normal to the isotropic basal plane near a semi-infinite crack tip is considered. In addition to having a discontinuous electric potential across the slip plane, the dislocation is subjected to a line-force and a line-charge at the core. The explicit solution for the model is derived by means of complex variable and conformal mapping methods. The classical 1/r singularity is observed for the stress, electric displacement, and electric field at the crack tip. The force on a screw dislocation due to the existence of a semi-infinite crack subjected to external electromechanical loads is calculated. Also, the effect of the screw dislocation with the line-force and line-charge at the core on the crack-tip fields is observed through the field intensity factors and the crack extension force. [S0021-8936(00)01501-4]

Screw Dislocations Emitted from a Blunt Crack in a Piezoelectric Material

2014 ◽  
Vol 891-892 ◽  
pp. 1742-1748
Author(s):  
Hao Peng Song ◽  
Cun Fa Gao
Keyword(s):  
Dielectric Constant ◽  
Screw Dislocation ◽  
Piezoelectric Material ◽  
Arbitrary Distribution ◽  
Dislocation Emission ◽  
Screw Dislocations ◽  
Blunt Crack ◽  
Series Form ◽  
Piezoelectric Screw Dislocation

The problem of a piezoelectric screw dislocation emitted from a blunt crack is dealt with in this paper. For an arbitrary distribution of the residual dislocation, the series-form solutions are derived. The results show that the force acting on the dislocation decreases with the value of the dielectric constant within the crack increasing. And the increase of the dielectric constant within the crack helps dislocation emission effectively.

A New Defect in Polyethylene Single Crystals

1973 ◽  
Vol 31 ◽  
pp. 70-71
Author(s):  
E. L. Thomas ◽  
S. L. Sass
Keyword(s):  
Single Crystals ◽  
Screw Dislocation ◽  
Small Distance ◽  
Dipole Model ◽  
Dislocation Dipole ◽  
Chain Folding ◽  
Black And White ◽  
Polymer Crystal ◽  
Different Types

In polyethylene single crystals pairs of black and white lines spaced 700-3,000Å apart, parallel to the [100] and [010] directions, have been identified as microsector boundaries. A microsector is formed when the plane of chain folding changes over a small distance within a polymer crystal. In order for the different types of folds to accommodate at the boundary between the 2 fold domains, a staggering along the chain direction and a rotation of the chains in the plane of the boundary occurs. The black-white contrast from a microsector boundary can be explained in terms of these chain rotations. We demonstrate that microsectors can terminate within the crystal and interpret the observed terminal strain contrast in terms of a screw dislocation dipole model.

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