LIGGGHTS® - User Forum

Hi,
Is there a way to erase all previously forces on CAD mesh before dumping new forces on it due to granular particles?
Thanks,
Ram

I am running LIGGGHTS with approximately 34,000 particles in a confined STL geometry with mixing paddles rotating to agitate the particles. I've noticed in my output (as .vtk files) that the order in which the particle positions are written change every 1000 time steps (regardless of how often I dump data). The "Lookup Table" for atom types at the end of the .vtk file changes correspondingly. Thus, if I have two atom types, visually the simulation runs smoothly.

Hi all,

I have identified a bug with LIGGGHTS, which is causing problems every time a run command is encountered in the input script. What I have seen is that the run command deletes all the forces and recalculates them, and I think that something is not done properly in the way the shear force gets calculated (ie in the way the last value of shear gets passed on to the pairs at the initial step after run Nsteps is found).

Hello, Christoph, i simulated a compression test, after compression, i want to remove the top plane. As i understand, it could be done by using unfix wall and i used unfix wall/gran/hertz/history, but i got 'Segmentation fault', could you help me? By the way, i used the latest version of LIGGGHTS.

P.S. I have read few similar discussions in the forums. Based on these discussions, the bug should be fixed, so i don't know if something i did wrong.

thanks,

Ada

Hi,
How can I define material properties of 3 types of particles? As, I want to use different friction between particle-particle(0.1), particle-bottom wall(0.0) and particle-side walls(0.7). Is this correct way of defining:

fix id all property/global coefficientFriction peratomtypepair 3 0.1 0.0 0.7 0.7 0.7 0.0 0.0 0.7

thanks,
Ram

Hi,

I'm a new comer to use LIGGGHTS. I can see that the characteristic velocity is a parameter used in the contact model of LIGGGHTS. What's its physical meaning and how to set it?

Thanks!

Jerry

Hi, Christoph, i simulated a compression test, but i found the particles crossed the top wall after compression. Hete is the simulation procedure. First particles are poured into a 0.5 m high cylinder without topwall, result is saved for restart; then in the restart file, the topwall is imported and moved to compress the particles. I couldn't find the reason for particle crossing wall. Can you help me? by the way the version i used is 1.2.6 beta.
Thanks,
Ada

Hello everybody,
I am having troubles with compiling the LIGGGHTS project. Everytime I call make makelist I receive the error "grep: cfd_regionmodel_*.h: No such file or directory". I am able to compile the project with g++ from terminal, but I need to fix this error because I want to compile the project with Codeblocks so I can debug it. I had the similar error with the atom_*.h and dihedral_*.h but I fixed it by installing the package CLASS2. I am using the serial_debug makefile.
I would greatly appreciate any help.
Thanks Tomas

Hi LIGGGHTS Users!

I have run into this problem where LIGGGHTS fails to restart in some cases (I guess when the particle-tri contacts are high) and exits with the following error:


Reading restart file ...
orthogonal box = (-0.00065 -0.00072 0) to (0.00065 0.00072 0.002)
1 by 1 by 1 processor grid
2198 atoms
Resetting global state of Fix zwallbottom Style wall/gran/hertz/history from restart file info
Resetting per-atom state of Fix zwallbottom Style wall/gran/hertz/history from restart file info

Importing STL file 'WireAssembly.stl'

Hi all,

I use the version 1.2.5 and I have this warning when spheres are in contact with triangular facets:

WARNING: Dangerous build in triangle neighbor list.

Please, can you give more information about this error message ?

Moreover, please can you indicate me the function where the neighbor list between spheres and facets is built. I use the function fix_wall_gran_hertz_history

Regards
JF