LIGGGHTS® - User Forum

Hi,

I have been dealing with a problem for several days now and I can't seem to be able to fix it.

I need to feed a transfer chute with 278 kg/s. I wrote fix insert/stream 278kg 278kg/s (mass mass rate) and simulate for 1 second. I was expecting to see 278 kg inserted throught my simulation but instead I only got 160 kgs approximately. No matter which values I used I kept getting the same result (WARNING LESS PARTICLES INSERTION THAN EXPECTED). I wanted to know if there is a reason why the sistem only seems to be able to feed a maximum number of particles.

I have been trying to fill a rotating mill volume by the insert/stream command. The commands looks like something below:
fix ins_balls all insert/stream seed 5330 distributiontemplate pdd_feed_balls maxattempt 1000 mass ${mass_of_balls} massrate ${feed_rate_balls} overlapcheck yes vel constant 0. 0. ${downward_velocity} insertion_face ins_face01 extrude_length 0.5


Hello,
I am viewing the LIGGGHTS results in paraview, but I am not understanding how to see the velocity, force, stress changes with time and how to draw the graphs in paraview.

Dear mates,

Dears,

I try to understand fix massflow/mesh command, but it doesn't work with a simple simulation :(
When I run it, the output file (massflow_mesh.dat) doesn't show the correct data, comparing with that I see in Paraview.

I use:
timestep 1e-6
E 5e6
fix mass_u all massflow/mesh mesh cad_base vec_side 0. -1. 0. count once file massflow_mesh.dat screen no writeTime

I attach the data123.tar_.gz with the complete input file (in.liggghts) and the corresponding meshes (stl files).

Regards,

Dear all,
i guess i found a wrong information in the documentation regarding the fix insert/rate/region command.
The corresponding list of general_keywords and their parameters contains the following line:
"once = value to signalise that isertion takes place only once (the step after the fix is issued)"

The value "once", however, is not allowed with this command, as my bash output was:
"'insert_every' = once not allowed"

Hello,
for a simulation, which uses spherical and non spherical particles,
I want to use a singelesphere and a multisphere approach at the same time.
But it does not work.
Every time, when "fix multisphere" starts, all of the existing singlespheres are deleted.
When the multisphere starts first, the simulation crushes shortly after the singlespheres are inserted,
saying
ERROR on proc 0: Too many neighbor bins (../neighbor.cpp:1778)
In both cases, the singlespheres and multispheres are seperated in two different groups and

hy friends....!

Hello, I would like to change the random position of particles before starting a simulation (I want to do different simulations only changing the starting distribution, just to compare average quantities).
Anyway I am changing the seed number in:
- particletemplate/sphere
- particledistribution/discrete
- insert/pack
in all these 3 commands and anything change! Impossible, there is surely a bug. What I see is that seed is not working.

Thank you,
rob1

Hi,

I was wondering if it is possible to apply/modify the gravitational field to particles after they cross a certain spatial coordinate. Based on what i have seen this could be done by creating groups of particles after they enter a certain region, but i can't seem to make it work.

Any thoughts on this?

Thanks,
Nicolas