LIGGGHTS® - User Forum

Hi everybody,

I am trying to install:

• fftw-2.1.5.tar.gz
• openmpi-1.4.5.tar.gz
• liggghts-2.0.6 from git clone from LIGGGHTS-PUBLIC.git

The results are following:

• The installation of FFTW went smoothly.
• The installation of OPENMPI went smoothly too. A simple “hello_world” test gave results as expected, as well as the “mpirun” command.
• The compilation of Liggghts went through without any major problem, except maybe the three lines at first:

Hello Liggghts Users,

I like to use DEM method for charged particles such that they can interact with external electromagnetic field. So I have following questions :

1) Is it possible to define external force field for example Electrostatic force as an analytical expression ?

2) Is it possible to use external field a numerical solution as calculated from other FEM package i.e. field values over a grid of points and use the interpolated field etc. ?

Sincerely,

Abhishek

hi
I have been looking into this last version of liggghts 2.0.6
it seems that compute coord/gran is removed from this last version, of-course it is possible to do this computation manually, with the help of conmpute_pair/gran/local. but it was such a good tool.
thanks anyhow

I'm hoping I'm encountering a common enough fault that someone will be able to help me without even seeing my code. I'm trying to import an STL file from solidworks into a LIGGGHTS script. Basically, I've substituted the mesh.stl file in the meshGran examples for my own file.

Dear all,

For a CFDEM project I tried to model interacting particles in a converging channel, to predict clogging behavior. To realise this I suspect to need cohesion behavior of the suspended phase.
In a 2d situation, also for a pure DEM calculation I get triangle neighbor list problems, even for very small time steps (1e-12) and particle 'explosion'; particles disappear when colliding.

Is cohesion in 2d unobtainable or is something else wrong? Attached my case and stl files.

Particles are quite large in comparison to channel size, just to check the behavior.

Both fix move and fix nve "count" as integrators, and if an atom is under both it will give us this warning. However, what if motion is only partially fixed? Then we still need an nve/nvt/npt integrator, so the warning must be generated.

Even if all DOF are fixed, it would be just a slight waste of time and not a serious accuracy problem.

Hi,

I am trying to simulate rocks that tend not to roll, is there a way that I can model translating only particles?

I tried using the rolling friction model with a high value of rolling friction;

pair_style gran/hertz/history rolling_friction cdt

with

fix m6 all property/global coefficientRollingFriction peratomtypepair 1 0.5

Hi Christoph,

my student Esperanza stumbled upon an inconsistency. For heat transfer area correction this command must be used:
fix heattransfer all heat/gran initial_temperature 300 area_correction yes
However, the docu suggests to use
area_correction values = on or off

Cheers,
Moritz

Hi,
is there a fix for pouring or inserting particles of complex shapes (like rods or rice grains), defined using the multisphere method or via fix rigid and pair_style hybrid granular molecular?
If not, is there such an utility for LIGGGHTS in preparation which will be made available for public usage in a forthcoming version?
Best
Eric

Hello:

I'm a novel user of LIGGGHTS, first of all I'd like to apologise for my simple question. I'd like to generate ten particles that their position, diameters and densities are different. How could I implement that in Liggghts?

Thank you in advance