LIGGGHTS® - User Forum

Hi all,

This is an issue I have had before & thought I had solved it, but have encountered similar problems with another model.

Hello,

I have been working with LIGGGHTS for a while now with the goal of setting up a cosimulation interface between LIGGGHTS and another simulation engine (geared more towards multi-physics) . I need to be able to represent complex geometries in the LIGGGHTS simulation with meshes and to get information about forces on that mesh. Does anyone know if there is a good way to get the forces on the vertices of a mesh (either via input script or using the source code)?

Nic

We have a scenario where our python application runs both Lammps and LIGGGHTS in the same process. However, we have a couple of problems doing so. We are trying to patch and fix the LIGGGHTS interface and therefore your help would be appreciated.

Dear liggghts community,

I am studying the granular flow in a hopper like geometry where particles enter the domain at the top and leave it at the bottom at a defined outlet. I would like to be able to control the mass flow rate at the outlet in order to study the flow behaviour at different discharge rates.

My questions therefore are: Is there a way to control the mass flow at the outlet other than changing outlet size? Maybe by deleting particles from a specific area at a certain rate?

Hello,

I am trying to read atoms stored in a dat file by using the command "read_data" but I get the following error:

ERROR on proc 1: Invalid atom type in Atoms section of data file (../atom_vec_sphere.cpp:1066)

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My input file is as follow:

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,