Problems with particle assignment and wall

Submitted by Maximilian Schwarze on Tue, 07/16/2019 - 10:39

Hello Community,

I'm working with liggghts for a job at my university. This work examines the contact surface between particles and the wall.

I have created a particledistribution with 4 different atom types and would now like to determine the tensions between the wall and the individual atom types.

For this I tried to combine a dump-stress command with a group assignment, but unfortunately this doesn't work.

dump dmpAllMesht1 t1 mesh/vtk 10000 post_hertz_ver/t1/t1_stress*.vtk stress window

Did I formulate the order incorrectly or is this possibility not possible at all?

Thank you very much for your help.

Max

mschramm | Tue, 07/16/2019 - 19:46

Hello,
Is your mesh part of the group?

I believe you are trying to output forces on the mesh caused only by a specific group of atoms.
I do not believe this is possible to do as mesh/vtk ignores the group_id. (https://www.cfdem.com/media/DEM/docu/dump.html)

You could make separate dump files for each group of particles and do post processing to get the answer you are looking for.
dump T1 t1 custom 100 t1_dump.* id type x y z vx vy vz fx fy fz
dump T2 t2 custom 100 t2_dump.* id type x y z vx vy vz fx fy fz
dump T3 t3 custom 100 t3_dump.* id type x y z vx vy vz fx fy fz

Then use post processing to isolate the particles next to the mesh and sum forces.