LIGGGHTS tutorial

I want to have single particle with large radius, for that i am trying to generate single particle but not getting success. Can I use stl file of sphere as a particle? I want to give all
material properties to it like density. I do not find any command to assign density to imported mesh.

Govind

Is it possible to vibrate the domain?

Govind

hi everyone i don't know how to get vtk files to see the animation in paraview from the tuttorial, i only get .stl files and all that files are the same in paraview.

Somebody could help me, please?

Thank you guys.

Hi, everyone. Here I am facing a problem about triaxial compression test of soils using LIGGGHTS, could someone help me?
I want to exert a constant confining pressure on a cube soil specimen. This may need a wall forcing the soil to be denser, how can I define the wall? Is there any good idea about such a simulation? Or could someone send me an example about such a stress-controlled test? Many thanks!

I run a bin tutorial code and I am getting this error along with this NOTE: "invoking MPI_ABORT causes Open MPI to kill all MPI processes. You may or may not see output from other processes, depending on exactly when Open MPI kills them." I can't understand whats going on will you please give suggestions to solve this error.

I could not run first tutorial (Example 1 – Bin flow) from the pdf. I had to modify it to be compatible with LIGGGHTS 3.X. Perhaps there are updated versions somewhere available online. Here is my version
It was recommended during the run to use "neigh_modify delay 0"
### Bin Flow Simulation
### This simulation involves inserting a set of particles into a cylindrical hopper,
### allowing them to settle under gravity, and then suddenly opening a stopper at the
### bottom of the hopper and allowing the particles to pour out. We track the
### flowrate of material from the hopper by tracking how many particles remain in the
### system as a function of time.

### Initialization

# Preliminaries
units si
atom_style sphere
atom_modify map array
boundary f f f
newton off
communicate single vel yes
#processors 2 2 3

# Declare domain
region domain block -0.138 0.138 -0.138 0.138 -0.0045 0.43 units box
create_box 2 domain

# Neighbor listing
neighbor 0.003 bin
neigh_modify every 1 check no

### Setup
# Material and interaction properties required
fix m1 all property/global youngsModulus peratomtype 2.5e7 2.5e7
fix m2 all property/global poissonsRatio peratomtype 0.25 0.25
fix m3 all property/global coefficientRestitution peratomtypepair 2 0.5 0.5 0.5 0.5
fix m4 all property/global coefficientFriction peratomtypepair 2 0.2 0.175 0.175 0.5

# Particle insertion
# 15485863, 15485867, 32452843, 32452867, 49979687, 49979693, 67867967, 67867979, 86028121, 86028157

fix pts all particletemplate/sphere 15485863 atom_type 1 density constant 2500 radius constant 0.0025

fix pdd all particledistribution/discrete 15485867 1 pts 1.0

region factory cylinder z 0 0 0.10 0.4 0.41 units box

fix ins all insert/rate/region seed 32452843 distributiontemplate pdd nparticles 150000 particlerate 150000 insert_every 1000 overlapcheck yes vel constant 0. 0. -1.0 region factory ntry_mc 10000

# Import mesh from cad:
fix cad1 all mesh/surface file meshes/hopper.stl type 2 scale 0.001

# Use the imported mesh as granular wall
fix geometry all wall/gran model hertz tangential history mesh n_meshes 1 meshes cad1
#fix geometry all wall/gran/hertz/history mesh n_meshes 1 meshes cad1
# model hertz tangential history
# Create stopper for funnel
fix stopper all wall/gran model hertz tangential history primitive type 2 zplane 0.0
#fix stopper all wall/gran/hertz/history primitive type 2 zplane 0.0

# Define the physics
pair_style gran model hertz tangential history
pair_coeff * *

### Detailed settings

# Integrator
fix integrate all nve/sphere

# Gravity
fix grav all gravity 9.81 vector 0.0 0.0 -1.0

# Time step
timestep 0.00001

# Thermodynamic output settings
thermo_style custom step atoms ke cpu
thermo 10000
thermo_modify norm no lost ignore

# Check time step and initialize dump file
fix ctg all check/timestep/gran 1 0.01 0.01
run 1
unfix ctg

# Create imaging information
dump dumpstl all stl 10000 dump*.stl
dump dmp all custom/vtk 10000 post/binflow*.vtk id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius
# dump dmp all custom/vtk 200 post/chute_*.vtk id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius

### Execution and further settings

# Fill the hopper
run 150000 upto

# Pull the stopper
unfix stopper

run 300000

Hello everyone
I am new to liggghts and am trying to simulate a rotating drum. I am having this error and I have not been able to solve it:

LIGGGHTS (Version LIGGGHTS-PUBLIC 3.8.0, compiled 2020-03-23-07:35:01 by root, git commit unknown)
Created orthogonal box = (-0.12 -0.12 -0.005) to (0.12 0.12 0.155)
1 by 1 by 1 MPI processor grid
ERROR on proc 0: Cannot open mesh file meshes/fandb.stl (/build/liggghts-YO7u74/liggghts-3.8.0+repack1/src/input_mesh_tri.cpp:105)
--------------------------------------------------------------------------
MPI_ABORT was invoked on rank 0 in communicator MPI_COMM_WORLD
with errorcode 1.

NOTE: invoking MPI_ABORT causes Open MPI to kill all MPI processes.
You may or may not see output from other processes, depending on
exactly when Open MPI kills them.

someone could help me please?
Regards,
Kardous

Hello,

thank you for your reply mschramm! it's effectively a problem relmlated to the mesh. Actually, I have some problem with how to create an stl file of the drum to be called i my model with liggghts afterwards. Do you know with which software is more simple to create this kind of files please?

In advance thank you for your help!
kardous

Hi,

When I try to download a file, the site redirects me to an error page that says.
"The requested page "/system/files/LIGGGHTS_Tutorial.pdf" cannot be found. "
The same goes for CAD files.
Could anyone share tutorial files with me?

Thank you,
Filip

Hi,

Same is here. I cannot download the pdf file.
Can someone share the file with me plz.

Thank you,
Sabrine

I tried to create a gaussian distribution using command line [fix pts1 all particletemplate/sphere 15485863 atom_type 1 density constant 8200 radius gaussian number 0.009 0.12] in LIGGGHTS 3.8 version.
but it shows [ERROR: Fix particletemplate/sphere (id pts1): invalid radius random style (../fix_template_sphere.cpp:199)]. what i have to do to rectify this error.

Hy All,

Is anybody who can provide me the tutorial document? When I click to the link, I got the following error message:
The requested page "/system/files/LIGGGHTS_Tutorial.pdf" could not be found.

Thanks in advance, Feri

Hello everyone,
My guess is that when cfdem changed hosting/redesigned the website, old upload links broke. This is why we can't download old files.
Some good news, I downloaded these tutorials and they have been sitting on my computer.
I have uploaded them to my github (https://github.com/schrummy14/LIGGGHTS_Flexible_Fibers/tree/master/examp...).

These are the raw files and have not been altered. You will need to update the syntax yourself. As I have time or if others provide pull requests, updated scripts will become available.

Hello all,

I am new to this DEM code and I would like to understand better how it works. When I click on this tutorial pdf I have the following error ;
"Page not found
The requested page "/system/files/LIGGGHTS_Tutorial.pdf" could not be found."
Can any one fix it or have another tutorial?

Thanks in advance,
Regards
Alex

Hello everybody,

I would like to have access to the turorial files.

Unfortunatly the link does not work. How is it possible to get this file.

Can please anybody shear a link?

Best regrads and thanks in advance

Mateus Kostka

I am a mechanical engineering student, and I am very interested in the method of discrete elements and specifically in the mesh-free methods, if anyone has any information, tutorials in pdf format that can provide me and be able to follow this learning path I will be infinitely grateful.
I am very interested in these topics, and I am doing my title memory in the application of these methods mainly in the free mesh method SPH mesh.

I will be attentive to your collaboration.

Greetings!!

hi

The links for LIGGGHTs tutorial and CAD file cannot be downloaded.

Hi guys,
I am trying to read data file for few time steps the particles are falling under gravity as per expectation but after few steps explosion of particle happens and all particles occupy the space defined by domain block. Anyone else faced same problem please give a solution?

The page for downloading does not work. Is there a way to download and view the tutorial?

Dear Chris,

Thank you for the great work. I tried to download the tutorial file several times but couldn't manage it.
Could you please tell me how I can download the files?

Best regards,
Majid

when i click on the tutorial document it loaded new page with text "The requested page "/system/files/LIGGGHTS_Tutorial.pdf" could not be found."

Hello everyone,
I am quaiet unfamiliar with LIGHHHTS and want to start. I tried downloading the tutorial PDF and CAD folder, but the link seems to be inactive or empty. Does anyone know how to access these files? If anyone has them, could you please share? Thank you!

I am not sure what was supposed to be in the tutorials mentioned in the initial post, however if you go to your installation of LIGGGHTS, there should be a folder with examples which should be good enough to get you up and running.