LIGGGHTS® - User Forum

Hi Everyone,
I am trying to simulate a case with a two-particle collision without gravity. Where one particle is fixed and another particle is moving with a certain velocity. However, after using the velocity command both particles are still stationary.
Please can someone highlight what mistake I am making?

My input LIGGGHTS script is as follow:

variable dt equal 1e-9
variable m_chamber equal 1.07e-5
variable m_chamber2 equal 1.07e-5

Hi guys

Does anyone know of LIGGGHTS is supported by ARM processors?

Hi everyone,

I simulated the uniaxial compression test using LIGGGHTS-WITH-BONDS by Richti, Is there any source or paper based on which I can help calibrate my model?
Or is there any source for calibrating a model in LIGGGHTS?

Regards,
Tannaz

I am implementing a contact model that allows particles to overlap. Is it possible to get information about the density of a region in space such that I would allow overlaps only if the density is lower than some given parameter? For example, lets say I have a system with identical particles (spherical, density = rho, radius = R). Suppose 3 particles overlap and occupy a region in space. Is it possible to get the density (3*rho, assuming they add up linearly) of the region. I am trying to build a contact model based by putting a bound on the density of a region.

I am getting error while inserting multiple particles as below:

```
If you perform one of the steps above LIGGGHTS(R) needs to be recompiled to generate the optimized code.

(/build/liggghts-YO7u74/liggghts-3.8.0+repack1/src/contact_models.h:364)
ERROR: Fix particletemplate/sphere (id pts2): invalid radius random style (/build/liggghts-YO7u74/liggghts-3.8.0+repack1/src/fix_template_sphere.cpp:199)

```

Any I idea , what did I miss here?

Here is my script

Hello everyone,

i am now working on a project with the LIGGGHTS_WITH_FLEXIBLE_FIBERS. I'd like to write out the number of the particles of each bond. Do you guys know, if it is possible? Any hint is appreciated.

Best regards.

I'm currently working on a particle packing simulation where I'm using a script to insert particles and simulate pressing. I want to extend this script to insert a second layer of particles on top of the first, with a different composition ratio of the same two particle types. After both layers are inserted, I would like to proceed with the pressing simulation. I have managed to insert the first layer successfully, but I need help modifying the script to add a second layer with a distinct composition.

I will provide you with some snippets of my script for simplification:

I simulated with multisphere in the liggghts-PFM version, acquiring a portion of the specimen via the displace_atoms command and delete_atom command. Both commands work, but after continuing to run, the intercepted portion goes back to its original position. displace_atoms doesn't seem to work, why is that? Is the particle location not updated correctly?

region bc block 0 1 0 1 0 1 units box side out
displace_atoms all rotate 0 0 0 0 1 0 30
delete_atoms region bc

Hello everyone,

Please be kind enough to explain me the meaning of following two errors.

WARNING: The following model does not yield consistent results with coarse-graining: cohesion model sjkr
WARNING: The following model does not yield consistent results with coarse-graining: rolling model epsd2

Hello everyone,

I'm currently working on a simulation involving a box where the particles inside undergo a volume expansion of 100%. My objective is to calculate the critical stress within the box by applying a compressive force, when the simulation box will alternately expand and contract.

Up to now, I have managed to simulate the expansion and contraction of the box and the application of force on its walls as separate processes. However, I'm facing challenges in combining these two simulations to run concurrently.