LIGGGHTS® - User Forum

Hi everyone,

I am trying to implement my own heat transfer model but it request a neigh list including non-contacting particles. I managed to do that by using cohesion model together with contact model, which built pair_gran list including non-contacting particles.
however, is it possible to modify some codes to directly use the neigh list before building pair_gran list? I have looked at the pair_gran_base.h, but not understanding clearly. could someone give some hints?
Thanks
Weijing

Hi everyone,

I'm using the following compute for accessing particle-wall contact information:

compute fc all wall/gran/local pos vel id force contactPoint

and the following dump command for writing that information to an output file:

dump walldmp4 all local 1000 post1000/fc*.dump c_fc[1] c_fc[2] c_fc[3] c_fc[4] c_fc[5] c_fc[6] c_fc[7] c_fc[8] c_fc[9] c_fc[10] c_fc[11] c_fc[12] c_fc[13] c_fc[14] c_fc[15] c_fc[16] c_fc[17] c_fc[18] c_fc[19] c_fc[20] c_fc[21]

Hi,

When I am restarting the simulation, I found that the particles are not moving (kinetic energy constant in output file), attached the image.
I tried uploading dump.stl (corresponding to restart file number) file using fix command and fixed wall but unable to solve the issue.
Can someone let me know if I missed any commands and how to fix this issue.
I am attaching input and outfiles and an image of this simulation.

Regards,
Shiva.

Hello, I am a beginner at using LIGGGHTS.

One quick question!

Is there any way to compute the force acting on the mesh ?
For example, if the mesh wall is enforced to move toward a pile of particles, then how can I calculate the entire force acting on the mesh?

Thanks,
Hakun

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.