LIGGGHTS® - User Forum

Hi all
How can I calculate best timestep for my program!?
Thank you

Hallo everybody,

I'm wondering how the contact force between particle and an stl-wall is calculated?

In the pair_gran doc the particle-particle contact force is explained, does it also apply to particle-wall contact?

If yes, what does the parameter m* stands for?

Kind regards
Philipp

Hi all
I have a problem.
When I visualaized my program,I see that 2 particles are stuck together!
and are separated from other particles!
I do not know why!
My program consists of 2800 particles and particles rotate in a ring.
friction=0.7
timstep=0.00001
Please help me
Thank you

Is there a limit to the amount of timesteps that a simulation can be run? Is it possible to run simulations up to, say, 100 billion timesteps?

Hi all
I have a ring that rotates around the Z axis . Is there any other way (except to change period) to determine the rotation rate?
*********
fix movecad1 all move/mesh mesh cad1 rotate origin 0. 0. 0. axis 0. 0.0 5.0 period 3
*********
THANK YOU

Hi everyone,

I tried to model a conical wall with the "fix wall/gran/" command. However, the result shows an error as "unknown primitive wall style". Does anyone know how to model a conical wall or how to modify this? Thank you.

I try to fill a region with insert/pack using four diferent particle radii from the same template. However, if I try to use more processor cores e.g. 24 instead of 10 then there are empty regions where no particles are inserted. This seems to be associated with using more than one particle, since if only one particle size is used then all regions are filled normally without regard of the number of processors.
I attach two screenshots showing the difference. The first using 24 cores and the second using only 10 cores but the same script.

Hello all
I have a problem.
This is part of my input:
fix boxwalls_z1 all wall/gran/hertz/history primitive type 1 zplane -0.025
fix boxwalls_z2 all wall/gran/hertz/history primitive type 1 zplane +0.025
I want to particles have friction together but do not have friction with the
zplans!
How can i ?
Please help me
Thank you

Hello,

I'm interested in exploring the capabilities of LIGGGHTS for generation of multi-spheres and simulation of non-spherical particles (using multi-spheres). Where can I find more documentation on LIGGGHTS capabilities for these subjects?

Thanks,
Andy

Dear all,

Does anyone know how to find the porosity in a packing simulation?
The only way I found is to calculate the total volume of the atoms knowing the number of atoms and their radius, but I can't know which volume of the entire container they fill because they don't fill the entire volume of the simulation box.

Thank you in advance