LIGGGHTS® - User Forum

Hello all,

I was trying to install liggghts source code following the steps provided on the web. The first steps run as in the tutorial but I had problem with "Set symbolic link for LIGGGHTS" command.

Here is some commands I used and their outcomes :

which mpirun
/usr/bin/mpirun

which mpic++
/usr/bin/mpic++

mpic++ -v
gcc version 4.8.2 (Ubuntu 4.8.2-19ubuntu1)

cd /home/"user"/LIGGGHTS-PUBLIC/src
sudo make clean-all
sudo make make fedora

Hi LIGGGTHS USER, Hi Chris,

as a commercial DEM code user, I have done realistic particle simulation several years ago. However, it's difficult to modify or add new contact model for commercial software. So I want to implement this job with LIGGGHTS. I have few question concerning the proper "atom_style" for rigid body:

Test example: three non-spherical particles drop under gravity. Their initial positions are (0 0 1), (0 0 1.5), (0 0 2.0) receptively.

1) Method 1: only "atom_style sphere" is used.

Hello, So I am running simulations of a simple agitator in a bucket (see agitator pic). I am interested in calculating the torque of a spinning agitator but my results seem odd when I use tangential history on the gran/wall and pair_style fix. When I plot the f_agitator_post[6] (from everything I read, it seems that this would be the torque acting on the agitator body in the z-direction), the values jump between positive and negative 2 N-m (see tangent_history_chart). This result seems rather odd because the blade is only spinning in one direction.

Hello all,

attached to this post there are scripts I made internal heat transfer in multispherical particles the changes involve:

Hi,

I'm trying to compute the forces in one axis that acts on a mesh, while the mesh moves through particles.
My attempt was the following:
###########################################
compute forcez all wall/gran/local force
compute actforce all reduce sum c_forcez[3]

thermo_style custom c_actforce
thermo 1000
thermo_modify lost ignore norm no
compute_modify thermo temp dynamic yes
###########################################

Hello ,

I am new user for LIGGGHTS. I'd like to simulate an oscillating box which has granular material in it.

I can create my particles,but I can not oscillate my box. The only useful command which I find is :

fix ID group-ID wall/gran model_keyword model_values wallstyle wallstyleargs general_keywords general

Here I can move the wall with using shear which is not useful for me.

Hope that you can help me.

Best regards,
Mohammad Farahani

Dear all,

I read all the references for the Hertz contact force model in the LIGGGHTS documentation 3.X, but I can not find the reference for the model constants gamma_n and gamma_t. In the papers I read there is no sqrt(5/6) in the gamma_n.

I want to know where the model constants come from. Is there anybody who can help me out?

Thanks.

Hi everyone! I'm very new to LIGGGHTS, and i'm trying to start example from the Tutorial (Example 2 - Continous Blending Mixer). When i want to start simulation i got this strange "Abort trap: 6" error. Is this happening because of errors in my input file? I'm using Mac, OSX 10.9.4 and latest version of Publicly releasers LIGGGHTS. I also attached my input file.
Thanks for any help!

Is there any way to produce a large number of rigid bodies with the grains in each rigid body arranged in a tetrahedral positions?
I have managed to produce small number of such rigid bodies by manually creating data-file and then "fix rigid group" atoms in each tetrahedron.
Now I can not think of a way to produce say 4000 rigid bodies like this.

Thanks

Hi all,

I recently installed ligghts/lammps with parallel support. When I try to execute one of the example scripts or load the module in a python console, the following is output:

>>> from lammps import lammps
>>> lmp = lammps()
Traceback (most recent call last):
File "", line 1, in
File "lammps.py", line 37, in __init__
raise OSError,"Could not load LAMMPS dynamic library"
OSError: Could not load LAMMPS dynamic library

What is the problem?

Thanks,
-Nabil