LIGGGHTS® - User Forum

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

Output Data from STL

Submitted by mbuys980411 on Tue, 03/05/2024 - 18:19

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?

Segmentation fault (11), Signal code: Address not mapped (1),Failing at address: 0x33

Submitted by rthek2 on Tue, 02/20/2024 - 23:54

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)

particles passing through plate in compression simulation

Submitted by pearllin on Sat, 02/10/2024 - 02:00

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

LIGGGHTS: Neighbour list

Submitted by PRASHANT KUMAR JHA on Thu, 02/01/2024 - 12:16

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?

LIGGGHTS-INL, how to observe the von-misses stress within bond

Submitted by WhoIsJH on Tue, 01/02/2024 - 06:40

Hi there

I'm a new in here. Recently, i have tried to simulate the scratch model with sharp tip and flat surface.
I'm using the LIGGGHTS-INL, which is possible to model continuum such as steel or concrete etc with a bonded particle method.

I can build my own model and explain how it work based on the theory.
But, I want to know how observe the stress within the bond. i think i need to modify some code with related to bond part.

Lattice creation

Submitted by krobot on Wed, 12/06/2023 - 12:16

Hello all,
Is it possible to create a lattice with a range of diameter such 2.0:1.0:20.0. And the diameter in the lattice will be randomly distributed. I want to create particle arrangement in a way that a bunch of small particles will covered a big particle. The diameter of the small particle will be different.

Taxonomy upgrade extras:

particle coverage

Submitted by krobot on Sun, 12/03/2023 - 13:19

variable x0 equal 0.0
variable x1 equal 10
variable y0 equal 0.0
variable y1 equal 10
variable z0 equal 0.0
variable z1 equal 10

variable regx0 equal -0.0001+${x0}
variable regx1 equal 0.0001+${x1}
variable regy0 equal -0.0001+${y0}
variable regy1 equal 0.0001+${y1}
variable regz0 equal -0.0001+${z0}
variable regz1 equal 0.0001+${z1}

Installing VTK

Submitted by Tannaz on Mon, 11/27/2023 - 00:55

I attempted to install VTK by following the procedure outlined on this website: [https://vtk.org/Wiki/VTK/Configure_and_Build]. However, I encountered a problem during the configuration step with CMake. I believe the expected outcome should resemble the procedure in the website but, I am facing an issue as shown in the attached figure. Can anybody help me with this problem?

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