LIGGGHTS® - User Forum

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

Set command error

Submitted by kashif saeed on Mon, 09/18/2017 - 17:48

Hi everyone,

I want to use the Set command with multi-sphere simulation but it gives following error.
set region factory property/atom VMoistureMass 7.065e-6

ERROR: Set command may not be used together with fix multisphere (../set.cpp:112)

please help me how to add moisture in case of multisphere instead of using set command.

thanks in advance

Installing LIGGGHTS on mac OS 10.12 (sierra)

Submitted by tjleps on Sat, 09/16/2017 - 21:04

This is a notice for people trying to get LIGGGHTS working on current mac os systems.

The Xcode8 command line tools GCC compiler will not successfully compile the LIGGGHTS source code with the couple most current versions of MPI. It's possible that using older revisions of MPI will work, I haven't attempted that. What will work is installing a more recent version of GCC. I stepped through this guide to making GCC on mac OS:

https://solarianprogrammer.com/2017/05/21/compiling-gcc-macos/

TIME VARIATION OF PARTICLE

Submitted by govind on Thu, 09/14/2017 - 13:03

Hi All,

I want to have time variation of particle through its history. Let's say there are 1000 particle and I have to concentrate on single particle that means variation of its properties vs time. I tried to search in LIGGGHTS commands but do not find. I am using paraview for post processing.

With regards,
Govind Sharma

Difference between compute wall/gran and fix wall/gran

Submitted by FelipeL on Wed, 09/13/2017 - 20:08

Hi!

I need to calculate the numbers of contacts between particles and walls, something similar to compute contact/atom, so i tried to determine the overlap on the mesh. My question is what´s the difference between compute wall/gran delta (overlap of the contact) and fix wall/gran contact_area overlap?.

For compute wall/gran delta, i got just one column of data, but for fix wall/gran contact_area overlap, i have 8 columns of diferents information depending on how many f_Id[x] i define.

Where can i check which information f_id[x] is showing?

STRESS/ATOM & COMPUTE REDUCE

Submitted by govind on Mon, 09/11/2017 - 06:30

Hi All,

In my work I have to do stress analysis for particles in domain(there is no stl file). With stress/atom and compute reduce I have some doubts, however I have gone through previous discussions on stress analysis. stress/atom generates a vector and we can access its elements like c_stress[1] to c_stress[6]. Now as explained in user document :

Error with store_force_contact in wall/gran and compiling Liggghts

Submitted by FelipeL on Fri, 09/08/2017 - 17:44

Hi all!

I´m trying to store the forces between particles-wall colision but when i add this line "fix granwalls all wall/gran model hertz tangential history mesh n_meshes 1 meshes cad1 store_force_contact yes" to my scritpt, i get the following message error:

Invalid fix style: "contactproperty/atom/wall" (../modify.cpp:820)

I´m using Version LIGGGHTS-PUBLIC 3.3.0. Im not sure if that its the problem, so I tried to upgrade LIGGGHTS to a recent version but when i use "make clean-all" ----> "make fedora" i get the following message error:

Mesh error

Submitted by z3490628 on Wed, 09/06/2017 - 10:25

Hi all,

I have tried to create meshes from gmsh. When I am trying to import to my liggghts script and run it, an error occurs saying "ERROR on proc 0: Bad registration of upcoming move. (../mesh_module_stress_servo.cpp:252)".

How can I solve this problem?

Particle sizes are not constant

Submitted by z3490628 on Mon, 09/04/2017 - 10:51

Hi all,

I aim to insert 8000 particles with same radius into a 100mm*100*100 cubic box. When I am trying to view the result in paraview, I have selected the 'radius' option from paraview to check the particles size. The result shows that the particles radius is changing throughout the timesteps. Can anyone help with this? Thanks.

# First Trial for model stimulation (real)

# Initialization

# Preliminaries

atom_style granular
atom_modify map array
boundary f f f
newton off
echo both

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