LIGGGHTS® - User Forum

Hi there,

I want to achieve a certain packing factor within a given region in my granular bulk material.

I tried to achieve a packing factor of 0.6 (Volume of solid material within the refered region / volume of refered region) within the region reg_ins by using this fix:

fix ins all insert/pack seed 100001 distributiontemplate pdd1 insert_every 1000 overlapcheck yes all_in yes volumefraction_region 0.6 region reg_ins ntry_mc 1000

What happens in the simulation is:

Hi all,

I'm working on a simulation where I just want to investigate the behavior of non-spherical particles during filling and emptying of a small container. I want to clump multiple spheres together to form elongated particles. For a few individual particles, I have done it already with fix rigid. This is quite expensive for several 1000 particles. What I want is to fill the domain with a continuous stream as in the example on this website (node/20).

Hello all!

I am trying to add a brand new stl file for use as a granular wall in a restarted simulation with mesh/gran/stressanalysis etc.. When the simulation runs, the KE is as expected but the all the stress values in the vtk dump file are 'nan' even though the imported gran wall is nowhere near the very few particles in the system. What to do? I suppose I could start a new sim using old particle position data instead of restart, but I would much rather restart

Hi all LIGGGHTS uesrs and developers

Does LIGGGHTS 1.5.2 support non-spherical granular simulation?
And if does, how to do a simulation with non-spherical granular?
May someone provide a simple example with input files?

Appreciate any help in advance!

If I have a cylindrical container created like this:
fix zwalls all wall/gran/hertz/history 1 0 zplane 0 0.3 1
fix cylinder_wall all wall/gran/hertz/history 1 0 zcylinder 0.052 1

should I expect the same effect on the particles if I wiggle the "region" than If I wiggling the two fixes written above with the same amplitude and period?

Hello,

I was watching the non-spherical pouring movie in the 'features' section. I was wondering where I could find an input file example for that. I don't seem to see it in my examples folder...

Thanks!
Zamir

Hi everybody,

to do a "quasi-2D" simulation set the forces in y-dimension to zero (fix setforce all setforce NULL 0 NULL) and use a very narrow box in the y-dimension where I insert my particles.
Now, all the particles have "nearly" the same y-position, but I'd like them to have EXACTLY the same y-position.
Is there a possibility to move the particles manually so that every particles has the y-position =0? How else could I handle this?

Thanks in advance,
kind regards

Sebastian

Has anyone developed a simple way to dump per-contact parameters such as maximum normal force per contact? For example, I would like a file that stored time of contact, location of contact, and max normal force.

I had this implemented in an old version of LAMMPS by creating a new pair style pair_gran__hertz_history_stats and by expanding LSHEAR and shearpartner in fix_shear_history.cpp, but these changes generated some interesting segmentation faults.

cheers,
Scott

Hi all,

After a long period without playing with LIGGGHTS, I come back and I want to re-install the code.

I follow the nice explanations to install the code from Git. I built the code and I obtained an executable lmp_fedora in the src file.

I try to run an example:
~/myliggghts/examples/LIGGGHTS/conveyor$ ../../../src/lmp_fedora < in.conveyor
LIGGGHTS 1.5 based on lammps-10Mar10

And nothing in the post folder !!!!

Please anyone, can tell me what I am doing wrong.

Thank you for your help.

Hi Somnath,
Here is dumpfile.
Thanks,
Ram