LIGGGHTS® - User Forum

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

Hi,
Is there a way to turn off the interaction between a frictional wall (imported using "fix mesh/surface") and a selected group of atoms in a simulation? I want the wall to act as boundary only for some atoms in the simulation and not for others based on the atom type. I tried using the "neigh_modify exclude" command but it does not seem to work for walls.

Any suggestions would be appreciated.

Thanks,
Tapan

Hi,

I just pulled the latest version (2.0.6), the particles are now changing temperature due to the hot conveyor. I have attached a little mpeg for anyone that is interested. Happy to have this working now!

Thank you,

Kirk

I just noticed that coord/gran doesn't appear in LIGGGHTS 2.0 - is this a feature that will be re-integrated, or was it removed deliberately?

Thanks! Mark

Hello,

I believe there is an error in shear modulus formula in the manual for pair_gran. Instead of

1/G*=2(2+nu1)(1-nu1)/Y1+2(2+nu2)(1-nu2)/Y2

there should be

1/G*=2(2-nu1)(1+nu1)/Y1+2(2-nu2)(1+nu2)/Y2

If we take two equal materials so nu1=nu2=nu and Y1=Y2=Y then accordind to your formula G*=Y/[4(2+nu)(1-nu)] and k_t=8G*=2Y/[(2+nu)(1-nu)], however according to the literature, k_t=2Y/[(2-nu)(1+nu)].

Hi,

I ran my case again with the latest version of liggghts (2.0.5), the analysis runs to completion without any errros.

When I postprosess the results, there does not appear to be a change in temperature due to the particles contact with the hot conveyor. Is there something that I need to change in my input script to have heat transfered from the hot conveyor to the particles?

Thank you,

Kirk

Dear all,
I would like to simulate a macroscopic object in contact with a granular system,
sort of a rotating ratchet.
I have the mesh and can insert it in my simulated granular system, but I would
like to have it "fixed" in space, and rotating around one (fixed) axis.
Basically I would need a mesh/gran/1dof fix :-)
I have solved translations by applying a strong spring that does not allow
my mesh to move away. However, it does still rotate with 3 dof, and I would
like to have just one.
Any suggestion/ideas/comments?

Hi everyone,
I am trying to install LIGGGHTS on Ubuntu 10.04. I notice that there is a folder named lmp_fedora which is important, however, I could find it in LIGGGHTS/LIGGGHTS-PUBLIC/src. In LIGGGHTS/LIGGGHTS-PUBLIC/src, there is just a file named lmp_fedora, and a folder named Obj_fedora.

I want to ask whether the folder of lmp_fedora is created by the step of make fedora? And if not, how should I do to create this folder?