LIGGGHTS® - User Forum

How can define a vector variable in Liggghts?

regards

Hi there,

I could just knew that FLUENT-DEM cannot be possible with the "dynamic mesh" problems so may be I have to shift to LIGGGHTS software for the DEM analysis.
I was trying to find some user guide for LIGGGHTS but I couldnt find any wherein I can learn from the core.
Can anyone help me, like how should I start learning LIGGGHTS, I might be having short time to learn though.
Actually I am working on the topic TRIBO-ELECTROSTATIC SEPARATOR for my thesis.

Thank you

I'm carrying out a simple indenter simulation, in which a cylinder is slowly pushed vertically into a box of particles.

Currently, I use the following to get the forces on the indenter:

...
compute fc all wall/gran/local id pos force
...
dump forcedump all local $e post/dump*.forcedata c_fc[1] c_fc[2] c_fc[3] c_fc[4] c_fc[5] c_fc[6] c_fc[7] c_fc[8] c_fc[9] c_fc[10] c_fc[11] c_fc[12]

When I visualise the forces (having created paraview compatible vtk from the above), it seems to be in the right place, and behave correctly.

Hello Everybody,

I have just download the pre-installed LIGGGHTS (Ubuntu 14.04 package) recently, I wanted to familiarize myself with it before installing it from source code.

I was looking at post-processing for a few days now, I installed paraview 4.0.1, but I still couldn't figure out how set the environment and create an alias correctly.

Hi,

I would like to consider in my simulation, that the material properties (coefficient of friction, Young's modulus ...) of the particles are a function of temperature. There's heat conduction from wall to particles and the particles near the wall are heated up, so each particle has a different time dependent temperature and hence different values of material properties.
My idea is to calculate the material properties every time step for each particle using their current temperature.
Is there any possibility to realize that? If so, how can i do that?

Hi All,

I would like to set the different temperatures to different particles, such as 10C, 20C, 30C, 40C ...100C to particle 1, 2, 3, ...and 10. I have read the commend of "set", it looks the ID could be atom ID range, type range, mol ID range, group ID or region ID, but it can not assign the value to each particles. I am wandering if the the commend "read data" could be used to complement this problems.

I'm trying to import an .stl file into a simulation. I receive an error message that states that 2 or more elements have too many neighbors. I've never seen this before so I'm not too sure what to do. Attached are my input file and my .stl file (renamed as .txt for upload). I make the .stl file in Solidworks if that helps.

Hi everyone,

Now I need to run a modeling of granular flow within an auger mixer. Approximately the total particle number is around 400,000. I have a server with 24 CPUs around. I wonder if this computer can handle this modeling? Anyone can give a hint about this ?

hi everybody,
I am trying to simulate a top and a bottom mesh platen contained by rings. these rings are made by "fix rigid" command using small particles (dia. 0.0002 mm). rings are filled by particles (dia. 0.001 mm). so I use these commands (briefly) :

atom_style granular
boundary m m m
newton off

communicate single vel yes

units si
read_data .../NGIgrains ############reads particles proprties and position

Hi, there
I am trying to implement a tri-axial compression test to calibrate the parameters for contact model.
There could be two geometry for sample, cylindrical and block, right?

How to keep the pressure constant on the meshed wall as the lateral wall area varies under compression?
And another thing, for example, for the cylindrical sample, how to implement a targeted force on the cylindrical wall towards radial direction?
cheers