LIGGGHTS® - User Forum

Hi!
Does anybody know, how I can make particles exiting a domain in LIGGGHTS-PUBLIC? I have defined the walls of the system as the STL-surface, and as the particles pass certain xy-plane, I want them to exit from domain. In the older version of liggghts in defined z-boundary (i.e. the xy-plane from where I want the particles to exit) inside the stl-surface and defined it as 'f'. Now I'm getting an following error:
ERROR: Mesh elements have been lost (multi_node_mesh_parallel_I.h:508)
Any ideas how to fix this?

- Timo

Hi,
For the calculation of stress/atom it seems only the neighboring particles are accounted for but not the contact forces that occur between a particle and a wall. Is this by design or something that might have been overlooked.

Thanks,
Tapan

Hello,

I'm running into a problem where my code exits early without giving me any obvious error messages. I'm simply trying to pour particles into my hopper. I'm submitting jobs batch style to a shared computer network.

I have the fix/insert set to use massrate. If I set the mass rate too low, obviously all the particles won't be generated before I run out of timesteps. However, if I set the massrate too high, for some reason the job will stop in the middle of execution. In this case, it stops after the second attempt to insert particles - step 1001.

Hi,
Can anyone who has used the cohesive model provide some references to realistic values of the cohesive energy density (J/m^3) parameter for some common materials like say wet glass beads or wet sand ?? I know that the value can vary quite a bit based on the amount of wetting and other parameters but it would help to atleast know some ballpark figures.

Thanks,
Tapan

Hello Liggghts Users,

I am new to liggghts and lammps too. I am trying to make changes in the example files (LIGGGHTS) by assigning external electric field using Fix. But I am unable to set charges to the particles using SET command.

The error says : Set command with no atoms existing.

Can somebody explain what I am doing wrong ? or how to assign charges in example file "in.conveyor". (*Sorry for such a stupid question*)

Thanks,

Best Regards,

abhishek

Hi,
Is there a repository from where I can download the previous version of LIGGGHTS (2.0.6) ? I installed version 2.0.7 and I am getting some peculiar results that I was not getting earlier. However before I blame it on the new version I wanted to rerun my code with the older version (2.0.6) to make sure.

Thanks,
Tapan

Hi everybody,

I am trying to install:

• fftw-2.1.5.tar.gz
• openmpi-1.4.5.tar.gz
• liggghts-2.0.6 from git clone from LIGGGHTS-PUBLIC.git

The results are following:

• The installation of FFTW went smoothly.
• The installation of OPENMPI went smoothly too. A simple “hello_world” test gave results as expected, as well as the “mpirun” command.
• The compilation of Liggghts went through without any major problem, except maybe the three lines at first:

Hello Liggghts Users,

I like to use DEM method for charged particles such that they can interact with external electromagnetic field. So I have following questions :

1) Is it possible to define external force field for example Electrostatic force as an analytical expression ?

2) Is it possible to use external field a numerical solution as calculated from other FEM package i.e. field values over a grid of points and use the interpolated field etc. ?

Sincerely,

Abhishek

hi
I have been looking into this last version of liggghts 2.0.6
it seems that compute coord/gran is removed from this last version, of-course it is possible to do this computation manually, with the help of conmpute_pair/gran/local. but it was such a good tool.
thanks anyhow

I'm hoping I'm encountering a common enough fault that someone will be able to help me without even seeing my code. I'm trying to import an STL file from solidworks into a LIGGGHTS script. Basically, I've substituted the mesh.stl file in the meshGran examples for my own file.