LIGGGHTS® - User Forum

How to create a discrete element library and use it in liggghts, whose particle geometry is totally irregular?
How do I assign percentage, the material being composed of a mix of particles of different geometries?

Hi,

I was trying to calculate the six-component from the global Stress tensor using fix ave/euler command. The dump looks like this for two cells:

SCALARS pressure float 1
LOOKUP_TABLE default
18.087371
14.514210
-0.000000
-0.000000
-0.000000
-0.000000
17.008131
10.089578
-0.000000
-0.000000
-0.000000
-0.000000

But probably ave/euler gives the trace of the stress tensor, how can I calculate all the global six components?

Thanks,
Sounik

Hi all,

I am seeking for an approach to changing the particle density from 2.6e3 kg/m3 to 2.6e6 kg/m3 after using my restart file. Does anyone know which command should I use for realizing this?

We normally set the particle density in command "fix particletemplate/sphere". As I see from the documentation, no fix_modify command can be applied to "fix particletemplate/sphere". So I want to figure out whether there exists a method that we can change the particle density during modelling?

Thank you very much!

Best,
Rachel

Hello,

I am performing some simple powder flowing simulations, and I am interested in seeing the migration of one or more particles through the flow, i.e. tracking it.

I tried defining a group using the following syntax :

region group_test block -0.02 0.02 0 0.02 0 0.04 units box
group group1 region group_test

Hi everyone

I'm trying to run a model that includes the multicontact model by Brodu et. al. (2015), in a cluster of my university.
In clueter it is installed LIGGGHTS 3.8.0 with Singularity.
The problem is that model do not run in cluster, but in my laptop it works. So I want to ask you if the multicontact model is not available to run in clusters, or is necessary to install something additional to run. The problem seams the MPI comunication doesn't work well with this model in cluster.

Any commentary could help me so much

Best regards.

Hi,

Hello LIGGGHTS Experts,

I wonder if can I prepare simple strain of a cylindrical metal sample in the LIGGGHTS program?
I tried to create some sample using multisphere. I'm attaching my file. Do I get one solid from these few points(atoms)? In what other way can I prepare the multisphere input file? Should I provide points manually? Should I fill the whole area of the figure with atoms? How to prepare such a file?

Hi,

I was trying to calculate the six-component from the stress tensor using fix ave/euler command. The dump looks like this for two cells:

SCALARS pressure float 1
LOOKUP_TABLE default
18.087371
14.514210
-0.000000
-0.000000
-0.000000
-0.000000
17.008131
10.089578
-0.000000
-0.000000
-0.000000
-0.000000

As ave/euler gives the trace of the stress tensor, how can I calculate the Stress tensor with six components?

Thanks,
Sounik

Hi all,

I am facing a strange problem. In my simulation, I use:

"group fines id 1942 753 976 1048 3765 5788......" (up to 1000+ particle ids)
"delete_atoms group fines compress no"

Hi all,

In my simulation, I have two particle size, namely small particles and big particles. Now I need to delete 10% of the small particles in my calculation region, does anyone know which command do I need to use?

Best regards,
Rachel