LIGGGHTS® - User Forum

Dear LIGGGHTS users,

Hi,

I am very new to multisphere model. I would like to know,

1) Is their a way to model two or more different "types" of particles in a single clump?
2) How can I model in different shapess?

Thank you.

Hey,
is it possible to set a variable to atoms in a group? So that for example all atoms in group 1 have have a atom variable that is 1 and for group 2 the same variable has the value 2 for each atom?
What I'm trying to do is subdivide the simulation region in many groups and calculate the density in these groups. But now for post process i want to set an atom variable which defines the density of each groups and all atoms in one group shall have the same density value.
Is this possible?
kind regards
joshua

Hi All,

I want to use cohesion model washino/capillary/viscous for the simulation.

I have four different types of particles in the simulation. And, I want to apply cohesion to only two types of particles. For the remaining two types of particles, I want to apply only gran model hertz (without cohesion).

Can someone please help me, how to implement this?

Any help will be much appreciated.

Thanks,
Narendra

Hallo everyone,

since few days we try to install the current version of Liggghts on our Linux cluster (Ubuntu 14.04). The first steps were no problem, but we always get an error during the compiling process:

hey,
is it possible to do the immediate evaluation of variables for an atom-vector? For a scalar its simply
variable v equal vol
variable v0 equal $v
But for atom vectors it is not possible to use $
variable x atom x
variable x0 atom $x
this would fail.
Is there a way to safe the initial state of an atom vector and use it in further atom vector calculations?

kind regards
Joshua

Hi all!

I was looking into literature to find out more about coarse-graining in granular simulations. I have found the paper "Three-dimensional discrete element models for the granular statics and dynamics of powders in cavity filling - C. Bierwisch Ã, T. Kraft, H. Riedel, M. Moseler (2009)" where the dimensional analysis is explained.

My question is: do I have to adjust the material properties used by the gran model hertz (Youngs modulus, Poisson ratio, coeff of restitution, coeff of friction) if I scale the particles by a certain factor?

In the newly released LIGGGHTS,serial multisphere method is included.

Hi all,

Could you please tell me how can I use hybrid mpi/openmp parallelization in LIGGGHTS ?

thanks in advance,

Reza,

Greetings,

I've been having the same error for some time when meshing with GID and then executing a LIGGGHT's program.
After displaying information about elements that have 6 neighs, instead of the expected 5 neighs, it shows this:

ERROR on proc 0: Fix mesh: Bad mesh, cannot continue. Possibly corrupt elements with too many neighbors.
If you know what you're doing, you can try to change the definition of SurfaceMeshBase in tri_mesh.h and recompile (../surface_mesh_I.h:504)