LIGGGHTS® - User Forum

Hello, everyone,

I am trying to add the Van der Waals forces in LIGGGHTS 3.2.1. The easiest way should be using the L-J potential. However, the L-j model is not available in the new Version of LIGGGHTS 3.2.1 any more. Could somebody tell me, how can I implement such contact loss forces in LIGGGHTS 3.2.1 without the potential, or is it possible to compile the solver with L-J potential model?

Many thanks!

Zhen

Hi all !

I have trouble with the potential energy computation. I always get a zero value for potential energy, whatever the conditions (sollicitation type, contact law, number of particles) and the compute used (pe, atom/pe).

I linked a small test case with an input script (two particles in periodic box, compressed at constant strain rate) and the thermo result I get in the log file. The particles indent in one another, but the potential energy remains zero. It seems that there is no pe computation in LIGGGHTS-PUBLIC/examples/LIGGGHTS/Tutorials_public.

I need to make a Triaxial Test but am pretty lost on how to fix all the errors I'm getting using LIGGGHTS. I'm running LIGGGHTS through cygwin, and was wondering if someone had already made a triaxial test that I could use. I found one online that I'm getting invalid pair errors for. Thank you very much for help.

Hi everyone
I was running my input script, but I got the following error:
'' Neighbor list overflow, boost neigh_modify one ''
and after that the simulation aborted at the first step.
Can you help me please within this problem?

I am inserting 10000 small particle in a spherical region and dragging them toward the center point to make a large agglomerate using the following script:

# initialization
units cgs
newton off
boundary f f f
atom_style granular
communicate single vel yes

Hello,
I'm trying to understand how LIGGGHTS calculates the heattransfer.
On the page:
http://nf.nci.org.au/facilities/software/LIGGGHTS/doc/fix_heat_gran.html
you can see, which formulars are used. But I don't get the the one in the middle.
I can't see how it is composed of.
Can some one give me hint or a Link to the paper?

Thanks for your help.

Best regards
RobertG

Hey

I followed the installation on: http://www.cfdem.com/media/CFDEM/docu/githubAccess_public.html step by step.

I use the following:

Ubuntu-Version: 14.04 LTS
Openfoam-Version: 2.3.0 and the additional libary "waves2foam" to generate and absorb free surface water waves.

If i use "cfdemSysTest" he gives back the following:

Hello,
currently, I'm working with rigid body and spherical particle.
I tried several methods to restart the simulation properly. With out any success.
Can someone pleas give me a hint?

Best regards
RobertG

How could I generate a bidisperse packing with 2 kind of spheres differing, for example, in diameter and density?

Hi to all,

for gran/hooke there is only one friction coefficient necessary. But in reality are 2 friction states possible: Sliding (or dynamic) friction and static friction. Is there any difference in Liggghts, or is this always the same?

Thx
Orangensaft

Hi everybody,
I had started out with LIGGGHTS a while ago, and know a few basic commands. I would like to know if it is possible to add mass (or) density for that matter, to any of our imported geometries. eg I am importing a box (.stl geometry) and pouring particles inside it , but i also require the box to be of a particular mass. Is there a way to do it ? , or are there any other alternate solutions ? Kindly help.

thanks
anand