LIGGGHTS® - User Forum

Dear LIGGGHTS users and its creators,
I have just started using LIGGGHTS for DEM Simulations. I have been using LAMMPS for around 2 years now for the same. I have seen that LIGGGHTS takes constant coefficient of restitution as input even while we use Hertzian model. I don't see the point of providing the coefficient of restitution as input when I am providing the Young's modulus and Poisson's ratio. Moreover, the coefficient of restitution along with collision time is a function of velocity and making coefficient of restitution doesn't make much sense.

I have issues concerning setting youngs modulus to a realistic value like 10 GPa. This requires insanely small timesteps.

In the documentatiom and in every thread on this question people say that it should not be bigger that 5e6 for si units or 5e5 for cgs.

But how would I go about modeling a simulation of a material that has a youngs modulus with magnitudes several times higher than 5e6 for the simulation?

Hello

I'm trying to perform the simulation of a chute, and I've been experiencing difficulties ... some I can solve by analyzing the forum, others I can not. My in.conveyor that I am using:

https://paste.ubuntu.com/25019462/

My problem is in section "PARTICLE INSERTION"; When I try to run with 'insert/stream' the Liggghts show me the erro:

Hi,

I am trying to run a simulation in Liggghts... when I run it by mpirun (with 6 threads) each processor use about much memory. The memory that have been used increased by time.

How could I reduce memory usage?

Any can help me with this: ''ERROR on proc 0: assertion failed''
_____________________________________________________________________________________________________________________
boundary m m m
units si

region domain block -3.7 2.6 -4.2 3.9 -4.5 1.95 units box
create_box 3 domain

neighbor 0.003 bin
neigh_modify delay 0 check no

Dear All
does anyone have reference for calculation of directional heat flux in the DEM?
The LIGGGHTS calculates heat flux based on distance of two particles in contact. I checked a code but I hesitate about the LIGGGHTS calculations.
Regards

Hi,

I need the properties of ROM ore (iron Ore), could anyone make it available?

Thanks.

Hi,

I was going trough the LIGGGHTS examples and had a problem after simulations 'cohesion' and 'insert stream'. I tried opening the post-files with ParaView 5.4.0-RC2 but the programm couldn't find the right reader for the post-dump files.
Apparently the dump-files are saved as dump_xxxx.cohesion and dump_xxxx.stream. (xxxx as a number like 8000)

What should i do to be able to view the results on ParaVew?

Thanks

Hello friends,

I am trying to use the mesh/tet command and so far I had no success.

I used 2 meshes in the study. The first mesh is a STL mesh. The second is a VTK mesh. Both meshes are in the same scale (mm). I scaled the meshes by 1e-3, because the unit system of the study is SI. If I run a test without the VTK mesh, everthing run ok. But if I run the study with the VTK mesh, liggghts return this error:

ERROR: VTK mesh file is incompatible with simulation box: One or more vertices outside simulation box (input_mesh_tet.cpp:298)

Hi

I'm trying to do a simulation with materials of different diameters (two materials). But I'm facing the following error:

"ERROR: Fix property/global (id m3): per-atomtype property matrix must be symmetric, i.e. N atom types require you to define N columns and N rows with N*N total values (../fix_property_global.cpp:158)"

In my settings are:

fix m3 all property/global coefficientRestitution peratomtypepair 2 0.8 0.8 0.8 0.8
fix m4 all property/global coefficientFriction peratomtypepair 2 0.15 0.15 0.15 0.15