LIGGGHTS® - User Forum

Dear friends,

Hi all,

In my simulation, I have particles with diameter d=0.1, 0.2, 0.5 and 1.0mm in the calculation region. I can obtain the total mass of all particle using the command "mass(all)". Now I want to know how to obtain the total mass of particle with d=0.1mm? Could anyone please give me any clues? Thanks ahead.

Best,
Rachel

Dear all,

I would like to check whether the value of the variable can be incremented or not? Here is a simplified example:

variable A equal 5
....
run 10000
Variable A equal "A*2"

Many thanks, Haithem

Dear all,

I am doing a compression test of soil particles and want to divide the sample into 3 parts with the same volume along the z direction. During the compression, the shape of the soil assembly will be compacted and thus the subdomain region also needs to be redivided. I don't know how to model such deformable regions so as to adapt the subdomain every step? Could anyone give me any clues? Thanks very much.

Cheers,
Rachel

Hello,

I'm having some difficulties in setting up a heat transfer model which involves heat transfer through a wall.

I've attached an image of my setup and what I'm trying to do.

I want to model heat transfer from a heat source (meshed wall A) through a powder (Powder B), through Wall B and onto Powder B.
As you can see from the attached image I cannot set up the model to allow heat to transfer through Wall B (which is an imported mesh).

Hey everyone,
has anyone tried using LIGGGHTS with python3? Right now I'm using python2, but i want to update it and use python3 . If I just try to use the install.py with python3 (and change the print structure to python3) I can't open files with a python3 script.

The python script only has the import and liggghts file call. With python2 it works fine but with python3 it says:

Hi all,

Form LIGGGHTS, I can output the contact forces acting on a selected particle in the soil assembly directly. Does anyone know whether LIGGGHTS can output the mean normal stress acting on a single particle and how to output this data? Some description of such mean normal stress (p'=sigma_ii'/3) can be seen in the attached picture.

Best,
Rachel

Hello,

I am having an issue with setting up one of my meshes as a heat source.

In my simulation I have two different meshes however I only want one mesh to be a heat source.
I assigned a constant temperature of 400 to cad2 as shown below but I get a nasty looking error message with this (copied to bottom of post)

Dear all,

Are there any easy ways to do following things for post results of pure particle flow, such as in paraview:

1) How to do temporal and spatial averaging for particle velocity? I mainly want to get the vector field like fluid flow.

2) How to track the particles in a region specified at time=0 s?

Looking forward to any suggestions. Many thanks.

Best wishes
Solient

Hi guys,

I use the move/mesh command to move mesh linearly along the z-direction.
I'm using the SI unit system. I set the velocity as 0.05 mm/s for the mesh.
fix meshmove all move/mesh mesh Cad1 linear 0 0 -0.00005
And my timestep is 0.00001

But after I check the result it moves way much faster.

I don't know how it happened.

Help me please.