LIGGGHTS® - User Forum

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

hi, everyone
I have a puzzle in the using of periodic boundary condition in the setting of particle flow.
the simulation box is cubic ( x:0~0.1, y:0~0.04, z:0~0.1).
I want to take a periodic boundary condition in the y direction, I dealed with it with the following steps:
firstly pour the particles and the related settings is:

boundary f f f
fix xwalls all wall/gran/hertz/history 1 0 xplane 0. 0.1 1
fix ywalls all wall/gran/hertz/history 1 0 yplane 0. 0.04 1
fix zwalls all wall/gran/hertz/history 1 0 zplane 0.0 0.1 1

Hi Christoph,
I have seen discussion in the forum about reading and outputting the contact forces between particles using compute pair/gran/local and the dump local command,
but I notice the compute pair/gran/local command can only output f_x, f_y and f_z respectively,
can I possibly output the normal contact force? If yes, how?
Also, I know that the current pizza can't convert the dump file of this compute to .vtk file, is there any method to do the conversion?

Thanks in advance.

Hi Christoph,
Following your reply in a post "how to speed up DEM"
I have taken a look at my timing statistics, and it seems the "other time" takes up the most of the time consumed.
Pair time (%) = 312.239 (32.578)
Neigh time (%) = 9.10633 (0.950124)
Comm time (%) = 16.8501 (1.75809)
Outpt time (%) = 0.128907 (0.0134498)
Other time (%) = 620.111 (64.7004)
Do you have any idea what is the "other time", How do I reduce it?