Hi all,
I am conducting pull-out simulation CNT/PE like polymer (without crosslink) to analyze interfacial shear stress ISS. I want to use fix smd to pull CNT out polymer matrix as follows
units metal
boundary p p f
… fix 1 cnt smd cvel K vel tether NULL NULL 100.0 0.0
…
My CNT/polymer simulation box is 79.6 x 79.6 x 64.4 Angstrom and the CNT SWNT(10,10) lenngth is 63.85
Could you tell me how I should choose the K value and vel value for fix smd.
By the way, I would appreciate if you give me some tips for the following questions
In pull-out process, the CNT will be pulled in z direction (non-periodic). I have used fix npt to relax polymer matrix in x, y direction (periodic), but not for z direction (non-periodic).
Could you tell me how I should choose the K value and vel value for fix smd.
Why not just try it and see how it works. You can adjust those params
to pull slower or faster. They're up to you and your system, so there
is no "right" answer.
Hi all,
I am conducting pull-out simulation CNT/PE like polymer (without crosslink)
to analyze interfacial shear stress ISS. I want to use fix smd to pull CNT
out polymer matrix as follows
units metal
boundary p p f
...
fix 1 cnt smd cvel K vel tether NULL NULL 100.0 0.0
...
My CNT/polymer simulation box is 79.6 x 79.6 x 64.4 Angstrom and the CNT
SWNT(10,10) lenngth is 63.85
Could you tell me how I should choose the K value and vel value for fix smd.
the papers cited in the fix smd documentation discuss
how to choose them and how they affect accuracy and
convergence of the results.
By the way, I would appreciate if you give me some tips for the following
questions
1. In pull-out process, the CNT will be pulled in z direction
(non-periodic). I have used fix npt to relax polymer matrix in x, y
direction (periodic), but not for z direction (non-periodic).
Dear Steve and Axel,
Thanks for your answer.
Regarding to the last question
In pull-out process, the CNT will be pulled in z direction (non-periodic). I have used fix npt to relax polymer matrix in x, y direction (periodic), but not for z direction (non-periodic).
Sorry because of not finished question. If I use fix npt for x, y direction but not z direction. When I pull it CNT but not time integration in z direction for polymer matrix as well as apply restrain as the paper I have quoted, the CNT will move without polymer atoms that are not dragged along with the CNT. I was wondering it is right based on physical model?
Dear Steve and Axel,
Thanks for your answer.
Regarding to the last question
In pull-out process, the CNT will be pulled in z direction (non-periodic). I
have used fix npt to relax polymer matrix in x, y direction (periodic), but
not for z direction (non-periodic).
Sorry because of not finished question. If I use fix npt for x, y direction
but not z direction. When I pull it CNT but not time integration in z
you are not making sense here. you are mixing up whether fix npt
is changing the cell dimensions or moving the atoms.
direction for polymer matrix as well as apply restrain as the paper I have
quoted, the CNT will move without polymer atoms that are not dragged along
with the CNT. I was wondering it is right based on physical model?
again, this doesn't make sense, if npt would not time integrate
in z-direction, fix smd in the same direction would have no effect as well.
Dear Axel,
Some days back, I had questions regarding to pull-out simulations for CNT/polymer. Could you please advise me what I should do in my situation
Suppose that I have CNT/polymer structure (the boundary is p p s) that was relaxed by fix npt in x, y directions under the pressure 1atm, the other z direction is non-periodic, so I didn’t use NPT relax in z direction in equilibration process.
Now I want to use fix smd to pull CNT out from the polymer matrix. If I understand right your explanation, I need to change boundary condition for z direction from shrink-wrap to periodic.
such that I can use fix npt relax (in 3D) for the CNT/polymer system in pull-out process. At this moment, the problem is to pull CNT through polymer matrix (not pull out). Is that right? If so, is there any way (technique) pull CNT out from polymer matrix but still use fix npt to relax the system in x, y, z direction.