LIGGGHTS® - User Forum

What is the best way to start learning liggghts as there are a lot of commands in the input script, so can you give some tips as to how to begin learning?

Hello everyone,

I am wondering why my simulation is showing spheres that are "floating". Does this happen due to the property of materials? In the screen shot, particles floating in "air" for multiple time steps and not moving much after particle collision. It didn't happen with my other practice scripts.

I have attached my script, could someone critique it please? This is my first time really exploring liggghts so my script is messy and I would really appreciate someone pointing out errors and tips.

I have attached a screenshot of what paraview is showing.

Hello!

I am trying to simulate about 7 million particles with size ranging from 0.0003175 m to 0.0031 m. During the simulation I have received the following error:

Memory usage per processor = 356.933 Mbytes
Step Atoms KinEng CPU
66000 1860696 980.5158 0
INFO: Particle insertion ins: inserted 1019560 particle templates (mass 6.060482e+01) at step 66667
- a total of 2880256 particle templates (mass 1.712086e+02) inserted so far.

SOLVED!

I wonder is there any limitation to the .stl-file sizes used for a simulation in Liggghts? I have two stls with around 80 MB each and my simulation crashes when i try to load them..

EDIT: I attached a picture. It just crashes and does not give any hint on what the reason is.. So is there a limit to files sizes maybe?

Hi All,

I am running cfdemSolverIB with a cyclic boundary but particle doesn't reappear after passing one cyclic side. Is there any suggestion to solve this problem?

best,
Arghavn

Hi,
I have been trying to solve for ellipsoidal and line type particles. I searched in many forums and available tutorials, but I could not find the syntax for the atom_style parameters for these types of particles. The only particle type I was able to find was a sphere and granular with a sphere template. Is there any place where I could find the fix parameters for particle insertion like this for other types of particles:

fix pts1 all particletemplate/sphere 15485863 atom_type 1 density constant 2500 radius constant 0.015

I'm using fix adapt to fill a volume to the correct packing fraction after an insert/pack operation:


compute rad all property/atom radius
variable diam atom c_rad*2
variable size atom ramp(1,4)*v_diam
fix grow all adapt 1 atom diameter v_size scale no


I'm trying to insert two populations of particles in the same region using:

fix insS all insert/pack seed 179426369 distributiontemplate pddS &
insert_every once overlapcheck yes all_in yes volumefraction_region $(v_fillIniS) region &
reg
fix insL all insert/pack seed 32453423 distributiontemplate pddL &
insert_every once overlapcheck yes all_in yes volumefraction_region $(v_fillIniL) region &
reg

Just confirming that the units for Young's Modulus are in the relevant simulation units.
ie.
for micro units, pg/(um*us^2)
The documentation does not specify whether it gets scaled or not.

Thanks,
Thomas