LIGGGHTS® - User Forum

Hello,

How to use this command please:
element_exclusion_list write

Problem is: 12 elements have high aspect ratio....
Mesh contains highly skewed element....
9 mesh elements have a really unreasonably high aspect ratio....

Hi all. I am currently adapting an old script of mine, replacing spherical particles being released down a ramp with multisphere particles. This has worked for the most part, but when I try to delete some particles from the simulation when the slide mass has settled and is ready to be released from the shutter, more and more particles keep disappearing between timesteps and some particles become fixed in place. The delete_atoms command successfully deletes the particles outside the region I'm interested in (and any spheres connected to those particles in their respective multisphere).

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)