Dear all,
Concerning to uniaxial deformation for polymer in non periodic boundary condition system. I will stretch the simulation box following x direction to get stress-strain curve.
Could you please make me clear some questions as follows:
In tensile performance, I will use fix wall using variable along with shrink-warpped boundary condition (s) incorporating with fix nvt. Do I need use fix wall for 6 box’s faces or only need fix wall for x direction?
Alternatively, Can I use change_box for stress-strain curve problems? If it’s is possible do I need fix wall command?
Which command can I use to eliminate residual stress that can take place in system?
Thanks for your consideration. Any suggestion will be helpful
Ha.
Dear all,
Concerning to uniaxial deformation for polymer in non periodic boundary
condition system. I will stretch the simulation box following x direction to
get stress-strain curve.
Could you please make me clear some questions as follows:
1. In tensile performance, I will use fix wall using variable along with
shrink-warpped boundary condition (s) incorporating with fix nvt. Do I need
use fix wall for 6 box's faces or only need fix wall for x direction?
It's up to you how to bound the other dimensions. Using fix nvt may
be problematic b/c you are adding a lot of energy to the system when
you pull on it. The Nose/Hoover thermostat may not be able
to adjust to it quickly, leading to temperature oscillations, etc.
I'd probably try fix langevin first.
Alternatively, Can I use change_box for stress-strain curve problems? If
it's is possible do I need fix wall command?
If you don't have a wall and the system isn't periodic, then
then there is no way to "pull" on the atoms. I assume your
polymer is tethered to the wall or else the wall doesn't pull
on the polymer either.
2. Which command can I use to eliminate residual stress that can take place
in system?
If you pull on the system why shouldn't there be stress?
The system will respond the way it wants to respond.
Dear Steve,
Thanks for you comment. Further to fix langevin, Do you mean I should use that command + fix nve to relax the system in tensile process?
Cheers,
Ha.