LIGGGHTS® - User Forum

Hi all,

I am going to insert particles in a box as follows, but this take too much time ( about 10 days with 120 cores)!
I would be pleased if anyone knows why!

--------------------------------------------------------------------------my input----------------------------------------------------------------
# insert granular particles into channel

echo both

atom_style granular
atom_modify map array
communicate single vel yes

boundary f f f
newton off
units si

Hi,

I cannot manage to give different properties to walls. in my simulations walls and particles are of two different materials.
I tried to assign different group ID to boundaries and particles but I get a command error which I don't find it.

Thanks
Mohammad

Hello! everyone. I have just started looking into LIGGGHTS for DEM simulation for my project.
Can anyone please help me with some resources to start with? I am kind of stuck. I'm not sure whether the software is installed or not. This is my first experience with a linux operating system. I was looking at the tutorials. But I could not understand how to run them. Where to write the code? How to begin with?

Any kind of help would be greatly appreciated.

Hi,

I was thinking about the packing due to gravity drop in an annular region. I used the pour command and got the particles in to a cylindrical region. But Iam not able to delete atoms in a new small cylindrical region inside the first cylindrical region to create annular region. The input command is like this

### Initialization
# Preliminaries
units si
atom_style sphere
atom_modify map array
boundary f f f
newton off
communicate single vel yes

# Declare domain

Dear all

Could you please let me know, where we can find stl files to run the benchmark examples given in the website (LIGGGHTS_Benchamrking)

There are several input files for batch processes and some continuous processes.

It would be good help for the beginners to run those becnhamraking problems and understand LIGGGHTS better

Thank you
Best Regards
Anki

Hi everyone,

dump dumpstress all mesh/gran/VTK 50 post/dump*.vtk id surfaceNorm stress wear cad

Gives me the mesh id and surfacenormal of all the mesh elements.
I wish to know the surfaceNorm of particular mesh id only at the point of contact (wall-particle) and not all of them.
Is there a way to call surfaceNorm in the source code? How can I modify the code?

Please help.
Thank you.

Compared with gedit for LIGGGHTS syntax highlighting, a better environment can be easily modified via geany, just adding new user file without any root permission for all Linux system. Moreover, it can be used as Integrated Development Environment(IDE).
Following images are the results, if you think it is useful ,please contact me by email--hwu13@mails.tsinghua .edu.cn. I don't know why I cannot upload my pictures .

Hi all,

I am trying to create groups of particles with specfic radius. When I create particles I use:

Hi,
i want to calculate local void ratio inside a sample. And i have tried two methods
For the first method, i have try to use "variable...mass"function to calculate the mass of particles in a given region i have set in advance . Then i can derive the local void ratio.but this method always overestimate or underestimate the void ratio because of the existing of particles intersecting with the region boundary.

Hi
maybe the request is not relevant to liggghts but I am using liggghts and have some difficulties in calculating volumetric strain in a specific volume such as a measurement sphere. I was wondering if anybody has developed a matlab code for strain tensor based on the ligggths results.
I will be so gratefull if you help me in this regard.
thank you in advance
ma