LIGGGHTS® - User Forum

I am using lj units to simulate sheared granular flows involving cohesive particles. According to 'LIGGGHTS Documentation', in lj units mass , sigma and epsilon of particle are set to one. In case of chemical bonds, epsilon is depth of the potential well. In case of granular matter what exactly is epsilon ? How do you define this quantity for granular matter ? Can somebody please help me ?? I am stuck here for a long time....

Dear community,
I used LIGGGHTS version 3.7.0 and want to run simple case (free fall by gravity of a single particle) without damping (gamma_n =0 and gamma_t = 0) , but my inputscript below doesn't work (any changes of gamma_n and gamma_t don't affect to movement) .
Can somebody help me with correct writing to change this parameters?

Best , regards Furkhat

#Contact model example

atom_style granular
atom_modify map array
boundary m m m
newton off
communicate single vel yes
units si

Hi everyone,

I have been working on a script for quite a while now and I am unable to print data to a text file.

I am working with two different multi-sphere bodies. I need to know the position, velocity, forces.... on the Centre of Mass and have this data printed in a text file (csv, txt, dat...). For this I am using the next work flow:

1.- Compute command:

#-------Define Compute to Calculate the Properties of Individual Multi-sphere Bodies (clumps)------#

We have downloaded the LIGGGHTS in our Linux server and getting the following error when we run
liggghts < binflow

I'm new to LIGGGHTS and enjoying DEM simulation. I have the following questions.

1. Can I use a cohesion model such as sjkr2 with hertz/stiffness? namely,

fix boxwall all wall/gran model hertz/stiffness tangential history cohesion sjkr2 primitive type 1 xplane 1

is possible?

2. If I use stiffness model with kn, kt, gamman, gammat specified, the values of youngsModulus, poissonsRatio and damping coefficient defined by

fix d1 damp viscous ...

Hello,

I'm running simulation on both LIGGGHTS 3.3.1 and LIGGGHTS 3.8.
When I run a simulation which includes a mesh rotation about 2 axis I get a different rotations.

The command's I'm using are:

fix movemesh1 all move/mesh mesh cad1 rotate origin 0.0 0.0 0.0 axis 0. 0. 1. period 8
fix movemesh2 all move/mesh mesh cad1 rotate origin 0.0 0.0 0.0 axis 0. 1. 0. period 2

Hi Liggghts Forum,

I have a compressed box of particles. The top layer of the particles needs to be moved horizontally in one direction(+y), while the bottom layer in the opposite direction(-y).

I created two groups (edge & edge1) for the particles in the top and the bottom layer respectively. My command for moving the particles are:

fix edge all move linear 0.0 0.08 0.0 units box
fix edge1 all move linear 0.0 -0.08 0.0 units box

Hello,

I am currently running simulations on 2 computers and have found a clash in the output of the same the dump command.

The dump command i'm using is "dump dumpstress all mesh/gran/VTK 1000 dump/dump*.vtk stress cad1"
However, the vtk dump files are formatted differently for each computer I use (and this is affecting my post processing work).

When I want to build my LIGGGHTS to be a shared library, I always got this problem. And I have install MPICH as the tutorials, but the problem is still exist. I am a new learner of liggghts, I will very appreciate if you can help me

I am trying to setup a simple one particle simulation with periodic boundary conditions (PBC) in LIGGGHTS and LAMMPS. I am finding that the atoms are lost in LIGGGHTS-PUBLIC (v3.8.0 ), whereas the same simulation except for a minor change in the communicate command seems to work fine in LAMMPS (17 Nov 2016). Please let me know if I have to include additional commands when I try to set up PBC in LIGGGHTS. I have attached the minimal examples for your reference.