LIGGGHTS® - User Forum

Hi everyone,

I am trying to perform a quasi-static uniaxial compression of an assembly made of a cubic box with inside 5000 particles randomly distributed with a radius of 0.00025 meters.

I am realizing this by using the "fix deform" command and a double loop. The external loop is for compression, the internal one for dissipation of kinetic energy realized with the "fix viscous" command.

I try to simulate an assembly with two group of particles. However, there is only one group of particles (ins1) added to the simulation while the other (ins2) is ignored. My code is given below. Could anyone tell where I did wrong? Thank you!

atom_style granular
atom_modify map array
boundary m m m
newton off

communicate single vel yes

units si

region reg block 0.0 2.0 0.0 0.1 0.0 1.0 units box
create_box 2 reg
group nve_group region reg

neighbor 0.001 bin
neigh_modify delay 0

Dear all,

Hello,

I am implementing heat transfer for granular media. I need to set two different temperatures: one for the boundaries(stl file) and another for the particles.
Is there any tutorial that can help or any other suggestion?

Thanks in advance,
Clara

hello everyone i am trying to apply a radial electrostatic force on particles in the documentation we can use only x y z axis but the force vectors are always pointing in a single direction i need them to be radial like applying constant stress to a cylinder and inclined if possible like using a conical electrode any tip is welcome thank you all.

Hello everyone, I need some help.

Currently, I am doing simulation in LIGGGHTS. My particles insertion area and surface have height approximately 0.02 in si units.

I would like to add some random height so that my particles drop from different height in the same simulations. Purpose of this is to bring noise on heights.

So I want to drop particles randomly at the height of 0.02 +- 10 % or 0.02 +- 20 %while running simulation.

Is it possible to add this idea in liggghts script?

What will be the command?

Thank you.

Hello
I am using "LIGGGHTS-flexible fibres"
For my study, I need to calculate energy stored in bonds such as normal, shear and bending. Is there a command to directly calculate that ?
If not, is there a way to find bond forces in normal, shear, moment, so that I can find energies by integration? As I can see the 'compute property/local ' can give bond forces in X, Y, Z not in normal and shear.

Thanks
Shubham

Hello everyone,
I was trying to move mesh up and down linearly,

I think somehow I ended up with moving down. My mesh file just goes down and doesn't come up.

I just want little bit of change in position.i.e move mesh little bit up and little bit down while doing simulation.

Right now I am using this command:

`fix move all move/mesh mesh cad linear 0.0 0.0 -1.0`

how can I control mesh while moving down so that it linearly moves up and down?

Thank you.

Hello everyone, I need some help.

Currently, I am doing simulation in LIGGGHTS. My particles insertion area and surface have height approximately 0.02 in si units.

I would like to add some random height so that my particles drop from different height in the same simulations. Purpose of this is to bring noise on heights.

So I want to drop particles randomly at the height of 0.02 +- 10 % or 0.02 +- 20 %while running simulation.

Is it possible to add this idea in liggghts script?

What will be the command?

Thank you.

Hello,

i want to import my particle positions from one Simulation to another. For Testing purposes i'm using the Simulation the particle positions are based on. After the filling process i want to replace the particles with those of the dumb.

I tried doing it with the read_dumb command as follows:

read_dumb dumb.particles_7455000 x y z radius box no purge yes format vtk

When i run it, it says:

ERROR: Unknown command: read_dumb dumb.particles_7455000 x y z radius box no purge yes format vtk (../input.cpp:259)