[lammps-users] How to realize unloading?

Hi everyone, I am doing the tensile test. I want to first enforce
tensile force on the nanowire, then unload it.

I have tried to use fix deform erate command. However, when I set the
erate <0, the following error occurred.

ERROR: Final box dimension due to fix deform is < 0.0
What is the meaning of this error?

So what is the correct way to unload after tension? Many thanks for any advice?

Best wishes,


Here is the code that triggers it:

    } else if (set[i].style == ERATE) {
      set[i].lo_stop = set[i].lo_start -
  0.5*delt*set[i].rate * (set[i].hi_start-set[i].lo_start);
      set[i].hi_stop = set[i].hi_start +
  0.5*delt*set[i].rate * (set[i].hi_start-set[i].lo_start);
      if (set[i].hi_stop <= set[i].lo_stop)
  error->all("Final box dimension due to fix deform is < 0.0");

You can see that you are running long enough at a high enough rate
that your box size will shrink past 0.0. Not good.