LIGGGHTS® - User Forum

Hi all,

I have a simulation comprising 250k particles of ~100 µm diameter packed loosely between two concentric cylinders. The packing is read from a file with read_data, and I simply want to let the packing settle under gravity for now (gravity is along the axis of the cylinder). I have two mesh walls defining the inner and outer cylinders, and as in the attached images no particles are in contact with the walls.

hi
I've got an experimental data-file containing coordinates of spherical grains, however there are some wrong overlaps between these spherical grains, i have tried to import this data file into the liggghts and let the package relax, so the overlaps are gone,
I have used fix_nve/sphere but the overlaps make the grains going on an exploding manner, even if i reduce the time-step, the same thing happens but in a longer time,
I have used fix_nve_limit and everything looks fine: after a little displacement the grains settle down,

I haven't seen much mention of this on the forums yet, but if anyone hasn't noticed LIGGGHTS 2.0 includes the ability to script LIGGGHTS from python, which can be very useful for building more complex run-time analyses, graph ongoing simulations, build a GUI to control certain aspects etc. etc.

I am trying to perform an analysis with particles moving along a hot conveyor. My script works fine if I leave out the temperature in fix mesh/surface. But when I add in the temperature, the analysis crashes after 25000 timesteps. Could someone help me understand what I need to change in my input script?!?!

Here is the script;

#Conveyor (600C) and Chute
atom_style granular
atom_modify map array
boundary f f f
newton off

communicate single vel yes

units si

region reg block 0.0 3.3 -0.3 0.8 -0.5 3.0 units box
create_box 1 reg

neighbor 0.01 bin
neigh_modify delay 0

Hi all:
Can some one tell me what's the mesh wall method used in LIGGGHTS?
I saw a topic contains about two thesis before. But I can't find it now.
Appreciate any help in advance!

Hi Christoph,

May I know when LIGGGHTS will support GPU?

Cheers,
Chuncheng

Hi,
I am having trouble finding instructions on how to install LIGGGHTS on Ubuntu 10.4.

I seem to have the source code, but do not know how to compile it.

Any help would be appreciated.

Kind Regards, Robert

Hi,

I want to build particles of complex shapes through using the multisphere approach with LIGGGHTS. I use:

atom_style hybrid granular molecular
(...)
neigh_modify delay 0 exclude molecule all
(...)
fix freezing all rigid molecule.

So far I did simulations where the beads composing a particle of complex shape have the same size. Everything works nice! Now the beads composing the complex particle can have different sizes and here I face a problem.

I want to dump a velocity profile, averaged over pre-defined layers. To my surprise, there's a LIGGGHTS fix that does exactly this (ave/spatial).

I'm a little confused regarding the options: Nevery, Nrepeat & Nfreq. I've been experimenting with it but I'm still not 100% confident of what I'm doing.

What I think each option does:

Nevery: fetches new values every N steps
Nrepeat: not really sure.
Nfreq: compute average every N steps.

Hi,
I install colloid package by typing
make yes-colloid
make fedora_fpic

and I get no errors, ending with :

text data bss dec hex filename
2472063 93744 24 2565831 2726c7 ../lmp_fedora_fpic
make[1]: Leaving directory `/home/vajiheh/LIGGGHTS/liggghts_GIT/src/Obj_fedora_fpic'
vajiheh@vajiheh-desktop:~/LIGGGHTS/liggghts_GIT/src$