LIGGGHTS® - User Forum

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

Dear all,

I was looking at the documentation of the hertz model and have a question about the following equation.
K_n = 4/3 Y*(R*delta)^(1/2)

I derived this equation from the hertz model and find the equation should be
K_n = 4/3 Y*R*^(1/2)delta^(3/2)

This result is also given by the wikipedia and some other papers.

Could anyone tell me which one is the correct one? This may have a great influence when the large cohesion is added.

Thanks,
Brian

Hello, everyone!

I have installed LIGGGHTS on our university cluster (CentOS 7.4) with VTK turned off. The compilation was complete and lmp_auto file was created.
I have copied the lmp_auto file to the folder with chute_wear example to check how it is working. However, when I tried
mpirun -np 4 lmp_auto < in.chute_wear
the following error appeared:

Dear all,

Hi, everyone
when I use the rolling_friction epsd3 for my simulation, I got the following error:

ERROR: Could not locate a fix/property storing value(s) for rollingStiffness as requested by rolling_model epsd3. (../modify_liggghts.cpp:411)

The epsd3 model request the definiton of rollingStiffness, but it is calculated as k_r = coeffRollingStiffness*k_n*rmu*rmu*reff*reff in the liggghts doc.

Any suggestion what I missed in my script.

# Material properties required for granular pair styles