LIGGGHTS® - User Forum

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

CGDEMproject/LPP.git

Submitted by LSmudge on Tue, 10/07/2025 - 10:54

I am a new user and while trying to clone the LPP git it asked for my github user credentials- those failed and so I cannot get this git. I tried searching on the project page and i cannot find this repository? Am I missing something or has there been a change/update that does not require this git. The documentation emphasis its significance. Any advice

Convex vs Concave

Submitted by MichaelMcF on Fri, 09/12/2025 - 17:50

I'm doing some packing simulations on the Aspherix Solver/GUI and am running in to a puzzling problem. I have normally been modelling complex particles as Concave shapes, but have recently moved to modelling 'simpler' cylindrical, Convex, pellets.

The particles I am using are essentially the same - effectively comparing a cylinder (Convex) against the same cylinder with various sections cut out (Concave). The Concave shape is decomposed into 34 separate elements.

Setting a velocity of all particles in a region?

Submitted by aran55336 on Tue, 07/22/2025 - 15:11

Hi there, I was wondering if there was a way of having a region of velocity in liggghts. The issue here, is that I can't simply assign the particles in the region to a group and then give a velocity to that group, as particles will be regularly entering and exiting the region in my simulation. I don't think theres a way to constantly recalculate the group is there?

Superquadric - Narrow/Broad Contact Detection

Submitted by ssjackson707 on Wed, 07/02/2025 - 15:14

Hi, I am working with superquadrics in the LIGGGHTS library.

I have compiled the library, with superquadrics enabled, and I do receive results.
In particular, I am investigating the narrow/broad phase contact detection discussed in here: https://link.springer.com/article/10.1007/s40571-016-0131-6

SUM THE FORCES OF DIFFERENT WALLS

Submitted by zhanshiran on Thu, 04/10/2025 - 11:46

Hi Everyone,

I hope you're doing well. I’m facing a challenge in my simulation and would appreciate some help.

I have added two different walls to my simulation using the following code:
fix 1 all wall/gran model hertz tangential history mesh n_meshes 2 meshes bot_wall top_wall store_force yes

Now, I want to calculate the force on the top wall, but the results from the compute command contain forces from both the top and bottom walls:
compute 1 all wall/gran/local pos force id

Particles' data stops reporting near bottom boundary in Periodic Boundary Condition setup

Submitted by MarcelUgo on Thu, 03/27/2025 - 14:29

Hi Everyone,

Could someone please help me with this challenge.
I am simulating the settling of particles in a periodic domain but notices that .liggghts files stops reporting any data once the particles gets to the bottom of the container. I am using an lbm-dem coupled code with liggghts version 3.1.0. The liggghts main input file is pasted below:

echo both
log ${dmp_dir}/log.liggghts

units si
atom_style ellipsoid # granular #
atom_modify map array

communicate single vel yes

boundary p p p
newton off

Modeling Superellipsoids using LIGGGHTS

Submitted by MahmoudY on Wed, 03/26/2025 - 18:15

Hi All,

I am working on simulating superellipsoids particles free falling into a cylinderical tank. I am aware that spehere in the code are easily modeled. However, I am not sure how to model shapes other than shperes, such as superellipsoids. I am studying the packing configuration of different particles shapes using DEM solver. I would appreciate your suggestions and comments on this problem.

Thanks in advance !

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