LIGGGHTS® - User Forum

Hi everyone.
I am working on a simulation that involves several impacts between particles; to gain a better understanding of the impact phenomenom I simulated a single impact between 2 particles and I noticed that although the friction coefficient was put to 0 and the coefficient restitution to 1, the conservation of energy and linear momentum was not respected.
Can I ask why? Is it related to the mechanism that the software uses to compute the contact forces or there may be some conceptual mistake I've made?
Thank you for your help

Dear all,
I want to simulate bonded material, can somebody give me some initial tutorial showing how to simulate bonded material.

For questions about Electrostatic force, please post here!

Dear all,

I am trying to add image support to LIGGGHTS. Based on the instructions found in the documentation, I believe I should be able to add the following lines to the Makefile.user file:

LMP_INC=-DLAMMPS_PNG
JPG_INC=-I/opt/pkg/filelib/libpng/1.6.34/gnu/7.2.0/64/opt/include/libpng16
JPG_PATH=-lpng
JPG_LIB=-L/opt/pkg/filelib/libpng/1.6.34/gnu/7.2.0/64/opt/lib

However, when trying to compile LIGGGHTS, I recieve the following error:

I have tried to push the v3.7.0 with BONDS (provided by Mr./Dr. m*****) to v3.8.0.

And I have met some issues. One of the key issues is how to set the random seed in fix bond create. Does anyone has experience on solving this issue?

Thanks!

Hi

I need to dump the local contact information between the particles for every step during the simulation.

But the whole script is in the loop for variable $a
Problem These particular compute (pair/gran/local) command is giving the error as follows
ERROR: Compute pair/gran/local (id cpg2): Need to define this compute before first run (../compute_pair_gran_local.cpp:127)
However the for variable equal to 1, script working fine, the problem starts with the next value of the variable

Hi all,

After I compile LIGGGHTS with make auto command and copy the lmp_auto into example/chute_wear, the mpi process had a segmentation fault which is :

Hi,

I am new to LIGGGHTS. I am looking into the example input script given in the LIGGGHTS documentation. I can see that the 'region' command was used twice in the input script. I do not understand why the 'region' command was used twice. What was the purpose of using the 'region' command twice? I am adding the example input script below. It will be a great help for me if you can explain the reason behind using the 'region' command twice in the input script.

Hi everyone!
I am working on a simulation that involves a rotating drum and I've been investigating between the different output I get when I set its rotation using the two commands I mentioned.
In particular, I am interested in the total force acting on the particles, therefore I used in both cases the mesh/surface/stress fix-style and I noticed that it leads to different results in both forces and trajectories of the particles.

Hello everyone
I am trying to conduct triaxial test using LIGGGHTS. My boundary is a cube made up of six STL files ,the size of one STL file is 0.2 meter. In the begining, they are crossed with each other, and particles are inserted in the center region, a cube with side length of 0.1 m.
I used servo command to accomplish isotropic consolidation.After that, I compute wall's position, unfix servo wall and fix new wall on the top and bottom.Using move/mesh command to move the top and bottom walls while lateral walls remain servo walls.