LIGGGHTS® - User Forum

UPDATE 7/14 - I've attached a file containing the CAD files for the tutorial cases.

*******************************************************************

I've recently worked up something of a tutorial for running some basic LIGGGHTS simulations that I hope others may find of some use. The attached document contains some sample input decks with some comments as to why certain commands are included. There is also a section at the end of 'best practices' compiled from some user experiences.

Comments, additions, or suggestions for improvement are welcome!

Is there a way to combine a rotary and linear motion so that the axis of rotation moves with the mesh?

When I apply more than one fix move/mesh/gran I do not get the motion I am expecting. I think I need a way to update the rotation point so that after the linear motion the rotation axis origin is updated. Can this be done with a variable that is updated in a for loop with inputs from the linear motion parameters?

Any ideas about how I can set something like this up?

Hi,

new versions are avaibale and some things changed.

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