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Geometric theory of defects in solids

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y<br />

Wedge dislocation <strong>in</strong> elasticity <strong>theory</strong><br />

R<br />

z<br />

−2πθ<br />

x<br />

r, ϕ,<br />

z<br />

ui<br />

- cyl<strong>in</strong>drical coord<strong>in</strong>ates<br />

{ u(),() r v r ϕ,0}<br />

= - displacement vector<br />

Boundary conditions:<br />

u | = 0, u | = 0, u | =−2 r, ∂ u | = 0<br />

r r= 0 ϕ ϕ= 0 ϕ ϕ= 2π πθ r r r=<br />

R<br />

vr ()<br />

u<br />

∂r( r∂ru)<br />

− = D - elasticity equations<br />

r<br />

1−<br />

2σ D =− θ , σ - Poisson ratio<br />

1 − σ<br />

D<br />

c2<br />

u = rln r+ cr 1 + , c1,2<br />

= const - a general solution<br />

2<br />

r<br />

2 ⎛ 1−2σ<br />

r ⎞ 2 2⎛ 1−2σ<br />

r 1 ⎞ 2<br />

dl = ⎜1+ θ ln ⎟dr + r ⎜1+ θ ln + θ ⎟dϕ<br />

⎝ 1−σ R⎠ ⎝ 1−σ R 1−σ<br />

⎠<br />

<strong>in</strong>duced metric θ 1, r ∼ R<br />

= −θ r<br />

θ - deficit angle<br />

11

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