shear strain at 0K

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1

Dear All,

I want to simulate the dislocations movement at 0K, so I need to apply strain to push the dislocation forward. I want to apply strain which develop gradually, and compute the stress add on the silp plane.
the dislocation was set in the middle of a film ( Only normal direction of silp plane isn’t periodic).
Can any one suggest me how to do this in lammps.

2

There are multiple commands in LAMMPS that can do this: fix move, velocity set, fix deform, etc. Please search the mailing list archive and you will find plenty of discussions.

Ray

3

Thanks for your reply.
I did search the mailing list , it seems that " fix deform " is a reasonable choice.

But the first sectence in " fix deform " description, it said “Change the volume and/or shape of the simulation box during a dynamics run” . my simulation is for statics case (0K)

4

If your simulation is static, then it has zero steps and is not a dynamic run - meaning you can use fix deform.

You can of course obtain stress-strain curve without dynamics, but the dislocation will not move with it.

Ray

5

I meant, “You can of course obtain stress-strain curve without dynamics, but the dislocation will not move without it.”

6

If your simulation is static, then it has zero steps and is not a dynamic
run - meaning you can use fix deform.

there also is the change_box command...

7

I’m a little confuse , how can i use fix_deform without run any step, since the command change the box every ‘N’ step ?

8

Why don’t you just try it? Also re-read the doc page, particularly these commands.

parameter = *x* or *y* or *z* or *xy* or *xz* or *yz*
  *x*, *y*, *z* args = style value(s)
    style = *final* or *delta* or *scale* or *vel* or *erate* or *trate* or *volume* or *wiggle* or *variable*
      *final* values = lo hi
        lo hi = box boundaries at end of run (distance units)