LIGGGHTS® - User Forum

Hi,
I'm trying to superpose two move/mesh rotate commands. The application is like a robot arm with two parts and the rotation axis of the second part changes with the movement of the first part.
The manual says, that for style rotate, the origin of the rotation axis would be in local reference, if there is a move command before. I think, however, that the vector of the rotation axis always remains in the same direction. Is this correct or is there a way to change the vector of rotation axis, according to a move / mesh command before it?

hi,
i m using a cylindrical mixer. i want to extract my data along a line probe. when i select plot over line it gives me results of two points not all particles on that line or probe. basically i want to extract a data w.r.t to x-coordinates. can anyone help me how to get a data of points along a line

When I run the provided examples, I can successfully output dump files, but I would like to visualize the simulation in Paraview. When I use custom/vtk to output vtk files, I get the above error message. I recently installed VTK and turned USE_VTK to "ON" in the Makefile.User. Has anyone else had this problem/how did you resolve it?

Thanks,

Jackson

Hey there,
I used the following commands and received the output files but i dont know how to post-process them.

compute CON all contact/atom
dump cn all custom/vtk 100 post/coornumber*.vtk id x y z c_CON

Should i use Paraview, MATLAB or sth else?

Hi, everyone,

I am working on mixing of granular particles in a cylindrical bladed mixer. I want to create force chain network as like given in the attached picture.
would you help me to create the contact force chain structure like that? how to get output from liggghts to built this structure.
thanks in advance

Hello,

I am trying to simulate the angle of repose of alumina. A picture of the simulation I am performing can be seen in the Figure attached. It is a funnel unloading alumina directly in the floor, and after a certain amount it should stabilize and one could get the angle of repose.

However, I am facing a weird behavior. After stop inserting particles, the pile of alumina (which until this point seems to have a correct angle of repose) suffers some instability and collapses a little bit, affecting the angle of repose.

Hi,

I'm new to LIGGGHTS and was trying to run the in.movingMeshGran example on the terminal. The input was "mpirun -np 4 lmp_auto -echo both< in.movingMeshGran" which produced the following output: "in.movingMeshGran: No such file or directory"

What may I be doing wrong? I'm certain the file exists and can open it using TextEdit on Mac to view it.

Thanks
C CH

Hi all,

I am currently trying to use Fix external pf/array command.

I am using a Python interface to LIGGGHTS-Public as the external driver. The Python Interface is build and wrapped according to the official documentation:
https://www.cfdem.com/media/DEM/docu/Section_python.html

Hi All,

I want to know id of an atom during computation for that I am using property/atom command like this

compute ID impactor property/atom id
variable aID equal c_ID[1]

here impactor group only has one atom. And I access this with v_aID. But it throws an error :

ERROR: Compute used in variable between runs is not current. Use the update_on_run_end option for computes to avoid this.

After following this error message I change the compute command

compute ID impactor property/atom update_on_run_end yes id

Hi Christoph,

Can you please tell me what this error is?

WARNING: New thermo_style command, previous thermo_modify settings will be lost (../output.cpp:725)
ERROR: Invalid keyword in thermo_style custom command (../thermo.cpp:819)