LIGGGHTS® - User Forum

Hi Everyone,

I am analyzing a sieve geometry for particle transfer. The CAD model of sieve plate is complicate with around 1 Mio. of tessellated faces. Hence, reading and "import and parallelization" of this taking huge amount of time. Is there any alternate way to speed up this time? I can't use the recently introduced model "massflow/mesh/sieve" fix command because most of modelling data require here is unknown.
I also tried converting the STL file to VTK using Paraview tool but it also did not work.
Any suggestion that I can try?

Regards

Hi everyone,

I am trying to simulate a rock under point load, similar to what is described in the LIGGGHTS-WITH-BONDS documentation in.bond. My model consists of different clusters, and I intend to start with two types of atoms (type 1 and type 2) that are randomly distributed within the model. Additionally, I want to define three types of bonds: bond1 between atom type 1 and atom type 1, bond2 between atom type 2 and atom type 2, and bond3 between atom type 1 and atom type 2. I have a couple of questions:

Hi everyone,

I am somehow a beginner in using LIGGGHTS, and I want to make a model consisting of different clusters using LIGGGHTS-WITH-BONDS. I aim to create a model with two different types of bond properties (stiffness and normal and shear bonds), and I want to assign atom bond type 1 to some atoms and atom bond type 2 to others. Is it possible with LIGGGHTS-WITH-BONDS? And is there any example that can help me?

Thank you Tannaz

Hello!

I am using LIGGGHTS FLEXIBLE FIBERS. I made flexible fiber from 50 atoms bonded togeather. I am cutting this fiber by blade and determing loads on blade. I want to make a fiber, which would better describe shape of real fiber so I let atoms overlap, which means I had to turn off pairwise forces. I did that by command neigh modify exclude (with this command I turn off creating list of neigh atoms). But when I use this command forces which were applied by command bond style also disapear.

I am inserting a plate (STL mesh file) into a LIGGGHTS simulation and moving it up and down in a bed of grains. I am trying to output data about the electrostatic forces on the plate but all I seem to be able to dump from LIGGGHTS is the position of the plate. Does anyone know if there is a way to output state data from STL files used in LIGGGHTS simulations?

how to make data file from the VTK file for LIGGGTS?
Explanation-I want to read particle's coordinates and velocities from the VTK file and I want to start new simulation from that VTK file. How to do it?

On a RHEL 9 cluster with VTK installed, why would this seg fault? I just used 'make auto' and OpenMPI 5.0.2.

mpirun -np 4 lmp_auto< in.chute_wear
LIGGGHTS (Version LIGGGHTS-PUBLIC 3.8.0, compiled 2024-02-20-15:56:33 by me, git commit bbd23c8521fe0a4f3f5bfd0d3dc9a7dddd68d90b)
Created orthogonal box = (-0.5 -0.2 -0.4) to (0.1 0.2 0.15)
2 by 1 by 2 MPI processor grid

Reading STL file 'meshes/simple_chute.stl' (mesh processing step 1/3)

Hi, I am having a lot of trouble installing LIGGGHTS on Apple Silicon, can anyone provide more detailed description on installation? Has anyone successfully installed LIGGGHTS on Apple Silicon?

Hello,

I am a new user of LIGGGHTS. I am trying to perform a compression test with a cylinder being pushed into a bed of particles, and plot the force acting upon the cylinder. However, I have noticed that my particles are simply passing through the mesh, and all the forces being outputted are 0. I am not sure what is going on - I have tried to fix this by decreasing the timestep and moving the mesh slower, but nothing has worked. I've attached my input scripts. Does anybody have an idea as to what may be causing this?

Much thanks,
Pearl

neighbor 0.005 bin
neigh_modify delay 0

fix pts1 all particletemplate/sphere 15485867 atom_type 1 density constant ${solid_density} radius constant 0.004
fix pts2 all particletemplate/sphere 32452843 atom_type 1 density constant ${solid_density} radius constant 0.00236
fix pts3 all particletemplate/sphere 32452867 atom_type 1 density constant ${solid_density} radius constant 0.001

How to set optimal value of bin size so that unnecessary force calculation for the neighbor list can be reduced? How this neighbor size is calculated?