LIGGGHTS® - User Forum

Is it possible to use a separate contact law (force vs displacement) on unloading versus what is used during loading? Thanks in advance!

Hi,

We often have the problem to restart a simulation after a specific timestep.
You can make reload-files every N-time, but I think this will cost a lot of time (in fact you are writing down the same information twice in dump- and reload file).

Thats why I coded a tool to transfer a .liggghts file (which was dumped with dump*.liggghts and inherits every data of a single dumpstep) to a reload.pour file.

I attached the code and a 64bit precompiled executable.
The ussage is: d2r INFILE OUTFILE DENSITY (because density is currently not dumped to liggghts-file)

Hi

I would like to impress a force on each atom depending on his mass, velocity an position. While searching through the manual i have found the fix command addforce. I have read "the vector is the total force on the group of atoms". So thats not what I need. But I couldn't find any other fix command that would enable my additional force. In the forum I've read that in a coming version of liggghts variables could be used in fix addforce. Is this in the newest version 1.5 possible? Would that help?
How would you impress an additional force to each atom?

I am trying to simulate mixing of granular particles in a rotary drum mixer. How can give different values to young modulus, coef of restitution, etc for particle particle interaction and particle vessel interaction cause.

Hello everyone!

I am new to this site and forum.
Therefore I want shortly introduce myself:

I am a student from Düsseldorf, Germany
working on my master thesis now.

My job is to simulate a ball mill for grinding processes.
It is similar to the one you have on this site.
A rotating cylinder with steel balls in it should be simulated.

I am new to LAMMPS and LIGGGHTS.
Moreover, I never used Linux, nor have I used or programmed in C++.

What is a best/efficient way to start?

Should I at first get familiar with LAMMPS/LAMMPS manual
or something else?

Hey all, I just wanted to share this. I'm working on a tool-soil interaction problem in which both the displacement of the soil and the deformation of the tool is important. I will be coupling LIGGGHTS and Code Aster to perform the simulation. I have started a blog to document my progress (and to keep me motivated!!!)

It can be found at http://coolsimulations.wordpress.com

Hello all, hi Moritz!

Because of the forum threat SPH and walls you find attached my input script.

@Moritz: Two mistakes were in your input script:

• Regions may not overlap in areas, which should be treated as walls.
• In your case the union-command creates additional convex corners, which are not calculated accurately.

I inserted also comments to my modifications.

I modified your script only for bug fixing. I did not check any physical properties (viscosity,...), time step, ...

Hello! Does anyone have any good ideas if I'm trying to create a follower force. In other words, I want a force that changes direction as a particle rotates. I cannot find any commands to create mobile coordinate systems on particles, is there another way?

Thanks,
Zamir

Hello dear liggghts community members !

I'm interested to simulate using the SPH pairstyle cooling and subsequent solidification of a mixture of 2 liquid phases.
I know there's a heat conduction fix in liggghts , but i'm not sure if the sph particle parameters actually depend on temperature\pressure so the material properties could change appropriately to liquid->solid phase transition.

Is liggghts capabale of simulating solidification ? What would be a good start towards this direction ?

Hi Christoph,

I was wondering, how do you generate non-spherical particles in LIGGGHTS according to the mesh scanned from Laser Scanner?

1) Simply fill in single particle inside the mesh manually with minimum number of particles?

2) or fill in automatically by means of certain algorithm according to the points or surfaces?