LIGGGHTS® - User Forum

Hello everyone,

I am running the Direct Shear Test and attempting to calculate the effective stress from the contact forces, as given in Potyondy and Cundall 2004.
Is there anyone that has successfully computed effective stress from the contact forces and compared them with the externally-induced effective stress (normal force/loading area)? Can you recommend me where to start?

Hello,
I am using LIGGGHTS to simulate a simple granular flow condition in which at first particles are inserted in a cuboidal space and one side of this cuboid is removed to allow granular flow. But I am not getting the values of kinetic energy, potential energy, coordination number from 'compute' command. Further, the same is not getting shown in Paraview. Please find the code.

atom_style granular
atom_modify map array
boundary f f f
newton off

communicate single vel yes
processors * * *

units si

Hi Guys

Does anyone have any advice for modelling deck of vibrating screens?

I have developed a mesh 2x1.8m with 12.5mm apertures in it.

I get the below error when trying to run my code.
what can I do to resolve the issue?

Hello
I am using LIGGGHTS-flexible fibres version.
In my simulation I use "dump mesh/vtk" to dump the data for a meshed surface.
dump dumpID all mesh/vtk 1 post/filename*.vtk stress stresscomponents meshID
The data gets stored in ASCII format, which looks something like this:

Hello all,

I am trying to simulate flow of particles from a hopper/silo. I keep getting the error stating that there's too many neighbor bins. I have look through a few forums and cant seem to find the solution.

I have set my neighbor bin size to 0.0029, which is 2 times the largest radius of my particles( 2*r_max). I have tried changing the young modulus of particles but still get the same error.

Hi,
I am unclear about the forces that we save in dump file as `fy` , `fz` and `fx'.

Are they contact forces of each particle?

If not, is there a way to save contact forces for each particles?
Any help would be appreciated.
Thank you

Hi Guys

Please refer to the attached input script.
The first 63 lines define the attributes of the simulation thereafter the rest of the input file just consists of moving the mesh based on results I attained from my Matlab simulations. The simulation runs for only about 0.589 seconds, however the full simulation should be 30 seconds.

If I remove all the movement of the mesh the simulation time runs without giving any issues.
The below is the last part of the terminal output.

Hi Guys

Please refer to my attached input file.
I am struggling to understand why I am getting the error "Too many atom sorting bins"
Can someone please assist?

MM

hello,
how can fix adapt command be used for superquadric particles? can some one please help?
thanks in advance,
narayani

Hi Guys

I am trying to use the rotate/variable command as per the below implementation.

fix move2 all move/mesh mesh cad rotate/variable origin 0. 0. 0. axis 1. 0. 0. omega 1

I get the following error when trying to execute my code.

ERROR: Variable name 1 for fix move/mesh rotate/variable does not exist (../mesh_mover_rotation.cpp:174)
(../mesh_mover_rotation.cpp:174)

Can someone please assist with the issue at hand?