LIGGGHTS® - User Forum

LIGGGHTS® related topics can be discussed here: discussion about models, installation, feature requests and general discussion

Error with store_force_contact in wall/gran and compiling Liggghts

Submitted by FelipeL on Fri, 09/08/2017 - 17:44

Hi all!

I´m trying to store the forces between particles-wall colision but when i add this line "fix granwalls all wall/gran model hertz tangential history mesh n_meshes 1 meshes cad1 store_force_contact yes" to my scritpt, i get the following message error:

Invalid fix style: "contactproperty/atom/wall" (../modify.cpp:820)

I´m using Version LIGGGHTS-PUBLIC 3.3.0. Im not sure if that its the problem, so I tried to upgrade LIGGGHTS to a recent version but when i use "make clean-all" ----> "make fedora" i get the following message error:

Mesh error

Submitted by z3490628 on Wed, 09/06/2017 - 10:25

Hi all,

I have tried to create meshes from gmsh. When I am trying to import to my liggghts script and run it, an error occurs saying "ERROR on proc 0: Bad registration of upcoming move. (../mesh_module_stress_servo.cpp:252)".

How can I solve this problem?

Particle sizes are not constant

Submitted by z3490628 on Mon, 09/04/2017 - 10:51

Hi all,

I aim to insert 8000 particles with same radius into a 100mm*100*100 cubic box. When I am trying to view the result in paraview, I have selected the 'radius' option from paraview to check the particles size. The result shows that the particles radius is changing throughout the timesteps. Can anyone help with this? Thanks.

# First Trial for model stimulation (real)

# Initialization

# Preliminaries

atom_style granular
atom_modify map array
boundary f f f
newton off
echo both

Different particle size distribution between input file and output file, smallest particles lost?

Submitted by Matteo on Thu, 08/31/2017 - 18:35

Hello,
I'm struggling to understand what is wrong with my simulation since I specify a particle size distribution in the input file which is not reflected in the output file.

Can anyone help me please? Basically it looks like I get a shift of the mean value of the PSD toward higher values in the output file.
It seems that this might be related to missing of the smallest particles in the output file? Not sure why they are not there as checking the log file all the particles seem to be inserted.

See below input file

Problem in forming a cubic with aligned particles

Submitted by z3490628 on Wed, 08/30/2017 - 12:05

Hi all,

I wish to insert particle into a 100*100*100 cubic. I would like to form the figure as attached with particles are settled under gravity and align with each other. (the one with blue particles) However, I couldn't able to form it and particles distribution are not similar to a cubic shape. (the one with grey particles) I have attached the figures and my script. Thanks for the help.

Problem with bond breakage

Submitted by liggghtschr on Tue, 08/29/2017 - 15:44

I am using liggghts-with-bonds and trying to perform an indentation. Unfortunatly the bonds suddenly break shortly after they are created(5519 bonds are created at timestep 50000 and they suddenly disappear after timestep 52500). They are not even under any stress. The torque in the bonds just before they break does not nearly reach the maximum. I tried playing around with the relevant parameters but can't produce significantly better results.
What am I doing wrong?

Dividing Domain into number of sections?

Submitted by kashif saeed on Mon, 08/28/2017 - 20:04

Hi everyone,

Can I divide my simulation domain into the number of section or parts in the paraview to find the number of particles in each sub section of the domain to find mixing index.

I have also attached the image of my simulation. I want to divide this into the number of subdomains to find the subdomain based mixing index.
Please help me
thanks

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