Output forces on granular walls (2d)

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1

Hello,

I red in the mail-list that it is possible to exert forces on walls by the setforce command (I appended the mails below). Because I simulate a granular particle system (2d) I use the fix gran/walls.
The doc to that fix says, that this kind of wall is a idealized wall - compared to rough walls, which are made out of particles.
Furthermore refers the doc of the setforce command, just to atom forces.

So if the gran/walls are not made out of particles, it seems not possible to output forces here with the setforce command right?

What else can I try to output forces on the walls?

Thanks very much in advance,
kind regards,

Sebastian

The fix setforce command stores the force you are asking and
you can output it with thermodynamics (or use it in other parts
of LAMMPS, like from a variable). See the doc page
for fix setforce and thermo_style.

Steve

2

I don't recall that email exchange. Other fix wall
commands (but not gran) store the forces
acting on the wall from the particles, so you
can output the values form those fixes. It wouldn't
be hard to add that storage to fix wall/gran - I guess
we've never had occasion to do it.

If your "wall" is particles, you can also output the
forces on those wall particles (or sum them and output
that).

Steve