PARADISCYL:Cylinder-Remove surface debris

Remove surface debris

ill Ryu and Wei Cai

There is remaining issue realted to the time step due to the small dislocation segments.This tutorial describes how to remove tiny dislocation segment in cylinder code.

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Algorithm

1. Searching for the surface node(node in Figure 2.(a))

2. Find the neighbor node(nbr1 in Figure 2.(a))

3. Check if the character of surface segment is similar to screw

  $1.0-\mathbf {b} \cdot \mathbf {\xi } <=\epsilon$ 

, where $\epsilon$ is a tolerance.

4. Given burgers vector, there are three possible slip planes. For example, if $\mathbf {b} =a[111]$, then possible slip planes are $\mathbf {n} _{1}=[1{\bar {1}}1],\mathbf {n} _{2}=[0{\bar {1}}1],\mathbf {n} _{3}=[{\bar {1}}01]$(See figure 2(b))

5. Compute projected forces on each plane. $\mathbf {F} _{i}=\mathbf {F} _{total}-(\mathbf {F} _{total}\cdot \mathbf {n} _{i})\mathbf {n} _{i}$

6. Based on the magnitudes of $\mathbf {F} _{i}$, choose slip plane of the surface dislocation segment.

(a)	(b)
Fig.2 (a)Schematic (b) Slip system $\mathbf {b} =a[111],\mathbf {n} _{1}=[1{\bar {1}}1],\mathbf {n} _{2}=[0{\bar {1}}1],\mathbf {n} _{3}=[{\bar {1}}01]$.