LIGGGHTS® - User Forum

Hello everyone
I turn to you to understand the wear model used in Liggghts. I know it is qualitative, but anyway I would like to have a numerical approximation to the wear that occurs.

Hi,
I'm trying to modify the bin flow tutorial example so that a fixed number of particles will be loaded from a data file like the "in.hydrogel_default" example in folder hydrogel_multicontact.
So, I deleted

region domain block -0.138 0.138 -0.138 0.138 -0.0045 0.43 units box
create_box 2 domain

and inserted
read_data data/input_06.data

Hello,
I am wanting to get familiar with the new atom style and thought it would be fun to try and
simulate flipping coins. This is what I have so far.

Dimensions of a quarter (approx)
variable r1 equal 0.5*${coin_diam}
variable r2 equal 0.5*${coin_thik}
fix pts1 all particletemplate/superquadric 86028157 density constant 2500 shape constant ${r1} ${r1} ${r2} blockiness constant 10. 2.

I believe this creates a "coin" that is "face up" with a diameter of coin_diam and a thickness of coin_thik

Hi,

In the output file, we find:

Pair time (%) = 0.00112569 (0.237618)
Neigh time (%) = 0.00865573 (1.8271)
Comm time (%) = 0.00514528 (1.08609)
Outpt time (%) = 0.000437766 (0.0924061)
Other time (%) = 0.458377 (96.7568)

Dear all,

I want to use the values of per-atom vectors at each time step in "compute property/atom" and check them in an if loop afterwards. I have written this part of the script for this regard:

compute ff all property/atom update_on_run_end yes fx fy fz
variable fmag atom sqrt(c_ff[1]^2+c_ff[2]^2+c_ff[3]^2)

How can I access the vector fmag at each time step in the if loop?

Thanks in advance,
Nazanin

Hello everybody,

I have the strange behavior that my simulation suddenly stalls and does not proceed. There is no error message. With one case, this behavior appears always around the same timestep. When I slightly modify the case, for example move the mesh a little bit or set particle heat sources a little different, the case either finishes or stalls at a different timestep. The problem is that I don't know how to tackle the problem.

Hi,

I was wondering if we can convert the vtk files of granular particles to stl file or directly export the particle as stl (using dump). I only found that we can convert wall vtk to stl but would like to know if this is possible for particles as well.

Thank you.

Dear All,

I would like to compare the output of compute contact/atom for the contacts count of each particle/atom (to calculate the number of contacts for each atom in a group) and compute pair/gran/local for the number of pairwise interactions or particle-wall interactions in the system.

compute contact/atom
compute atomtrack all contact/atom
dump collide all custom 100 CSVs/dump*.doll.csv c_atomtrack

This question comes often. I wanted to answer it with a picture but pictures in replies are not allowed.

In short, use the calculator filter and calculate the magnitude of the force with its components.
THEN use the tube filter. You can scale the chains using the newly-calculated value

Hello everyone, I have made a small tutorial especially for Spanish speakers, any errors you find please let me know since I have been using liggghts for a short time.

Hola a todos, he realizado un pequeño tutorial en especial para las personas de habla hispana, cualquier error que encuentren porfavor haganmelo saber ya que llevo poco tiempo utilizando liggghts