LIGGGHTS® - User Forum

Hello, I was wondering if there's any way to group atom types together.

I'm clumping multiple spheres together to act as one particle. Each aggregate particle requires a "fix rigid" on a group, which is works fine. The pain is that the "fix property/global" requires vectors (peratomtype) and matrices (peratomtypepair) of parameters, even if they are all the same material (have the same parameters). For a few particles, it's no big deal. More than a few, and it's very tedious.

In my mind, I'd like the following to work (in pseudo-code):

Hi Chris,

I wonder how to read pre-defined data (x,y,z, radii, density) for atoms input.

For generation of particles with irregualar shapes, provided that I have a individual input file 'particle1.dat', and the content is like this:

// x y z radii density
-2.12 1.32 1.49 0.061 2202.2
-1.32 3.65 1.47 0.043 2044.5
1.65 2.67 1.51 0.023 2051.5
2.76 1.98 1.23 0.034 2107.2
....
// total N spheres

Hi!
I would like to create a BOND between particle and the face of an obstacle at the time of impact. what command I can use on LIGGGHTS?.
And, what are the "bond_type" commands can accept cfdem code?

Thanks~~~~~~~!!!

Hi everybody,
Some one can help me to install ligggths on ubunto v 13.
many thanks,

DEM

Hi all
how can make particales with two different sizes(just 2 sizes: r=1 & r=2)in liggghts?
Thank you

Hi all,

I try run a simulation with small particles, for this I use two distributions of particles with radius 0.0001 and 0.00015.
The simulation run fine, but when the particles in contact with the geometry jumps far away beyond the box.

For example, I modify the example "chute_wear" and just change the radius of particles and the results are like i said (
see attachment).

Any idea for help me in this problem?

Regards,
Felipe

Hi all

I'm running a simulation with cohesion model.
I would like to get the value of normal contact force and cohesion force separately, is there anyway to dump the cohesion force or how can i access the variable Fn_coh in the source code?
Thank you for your help!

Best regards

Duy

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