[lammps-users] (no subject)

Dear all,

I want to simulate a nanowire which is subjected to the application of stress. This stress is supposed to be applied via velocity to the both ends of the nanowire. The command I use is “fix 1 bondary1 move linear -1 0 0 units box” in which the bondary1 is a group within a region of atoms in the left side of the nanowire.“group bondary1 region left_side”( the region is defined). (The same commands are used for the right side).
After doing all these, the program is run and the result is separation of this group of atoms from the left (and right) side. It sounds like atoms are not linked with each other.
Does anybody knows about the reason of this phenomenon?
Any help would be appreciated.
Thank you in advance.

Yours faithfully.
S.Yousefi.

separate.png

Dear all,

I want to simulate a nanowire which is subjected to the application of
stress. This stress is supposed to be applied via velocity to the both ends
of the nanowire. The command I use is "fix 1 bondary1 move
linear -1 0 0 units box" in which the bondary1 is a group within a
region of atoms in the left side of the nanowire."group bondary1
region left_side"( the region is defined). (The same commands are used
for the right side).
After doing all these, the program is run and the result is separation of
this group of atoms from the left (and right) side. It sounds like atoms are
not linked with each other.

the simulation code does what you tell it to do.

it does not check whether this is meaningful or correct.
if you move atoms forcibly in opposing directions, they
will come apart at some point, regardless of the interactions
between them.

Does anybody knows about the reason of this phenomenon?

yes. PEBCAC.

axel.

You may want to decrease the applied velocity and see when the problem starts. Also it is a good idea to fix one boundary and apply velocity on the other with a ramp velocity on the group of atoms between the two boundaries to avoid the sudden jump.

Regards,
niaz