LIGGGHTS® - User Forum

Hello,
I am trying to calculate the local void fraction in a bed having motion. Can anyone help me to understand how can I calculate the voidage in a selected region? Is it possible to calculate void fraction during post processing in paraview, if the simulation has been already done without dumping the mass or volume of the particles in the selected region? (I am using only DEM not CFDEM coupling).

Thanks and Regards,
Aks

Hi everyone,

I am trying to simulate an assembly of bonded particles and using the software LIGGGHTS_Flexible_Fibers by mshramm. The script of my simple insertion simulation is:

# Constant settings
atom_style hybrid granular bond/gran n_bondtypes 1 bonds_per_atom 6
atom_modify map array
boundary f f f # will change to f f f boundary to save time
newton off
#echo both
communicate single vel yes
units si

region reg block -0.05 0.05 -0.035 0.035 0.0 0.025 units box
create_box 2 reg

Hello,

I am running a simulation about granular flow with around 20,000 particles, among which there is one special particle (called "intruder"). Right now, I would like to change the shape of the "intruder" from sphere to cylinder (superquadric), while keeping the shape of other particles as spheres. So how could I do it?

My current "intruder" particle creating code are like:

create_atoms 2 single ${xintr} ${yintr} ${zintr}
group intruder type 2
set group intruder diameter ${dl} density ${rho}

Thanks!

I am trying to create a simulation where particle will take some specific position.

Primary job terminated normally, but 1 process returned
a non-zero exit code. Per user-direction, the job has been aborted.
--------------------------------------------------------------------------

SIGINT/SIGTERM caught - Writing restart on next occasion and quitting after that.
--------------------------------------------------------------------------
mpirun noticed that process rank 0 with PID 0 on node user exited on signal 9 (Killed).

While I was running a script, the system crashed with the above message.

ERROR: Invalid atom style (/build/liggghts-YO7u74/liggghts-3.8.0+repack1/src/atom.cpp:459)
I an trying to use Superquadric particles but I am unable to use even though I enabled it in make file and recompiled the code. Can anyone please tell why does the error pops up?

Hello all,
I am Tarun from India. I wanted to install Aspherix basic in my system. But, while purchasing, I noticed that there is no option for "India" in the "Region" drop-down. Thus, I could not buy it. Can anyone please help me with this???

I really appreciate any help you can provide.

Regards,
Tarun

Hello Community,

I have a question regarding the implementation of the contact models. Like I understand and has been discussed allready in the forum Liggghts follows the integral implementation of the spring force according Di Renzo and Di Margio. Thats fine. I am more unsure about the implementation of the damping force and the coulomb criterion.

Like i understood from literature there are 2 ways:

1) First check tangential spring forces for coloumb considering the normal spring force and than add the damper afterwards in both cases if necessary:

Hello,

Does LIGGGHTS have the linear spring-dashpot contact model? If not, how can it be implemented?