LIGGGHTS® - User Forum

Hello,
I am seeing a problem when running a restart file.
The past simulation I had used a plunger to compress particles in my geometry.
I am now reading in my restart file and swapping to a different size plunger.
When I use the fix mesh/surface/stress command and state that I would like to
position the plunger at x,y,z, liggghts' positions it at 0 0 0..... I am stumped on
what could be causing this. I tried moving the file outside of my domain and
liggghts recognized that I did this but during the run, the mesh is back to 0 0 0.

Hi,
I have a problem with multisphere particles simulation.
when i use same case for simple spherical particles mixing, my results are good but when i used multisphere particles ( 2 or more sphere clumped together to form particle) then particles becomes cohesive and no mixing occurs between particles. i created multisphere particles according to code given in following link
https://www.cfdem.com/media/DEM/docu/fix_particletemplate_multisphere.html

Very new to LIGGGHTS. Tried to set up my first simulation: particle dumping from a cone into a cylinder. I see this error:

Hello,
I was going through the source code and came across this function, and I was looking to see if there was any more information on it.
I was able to get it to work and it does what I have been using MATLAB to do.
I am working with the bond/gran model and have been using MATLAB to spawn in my fibers.
However, the fix_template_multiplesphere function is doing (almost) what I want.
I say almost because it seems that the code is only checking if "starting node" of this template is inside the boundary

Hello people. I made another thread in developer forum, asking how to get the force in a simulation using granular bonds. The problem is that the values shown in dump files, aswell as the values calculated with compute property/local are way low than they should be (for the example i uploaded it should be around 31N, and its showing in both cases something close to 1e-6).

I tried running the simulation at 64, 128 and 256 cores, with the same in file and the executable. The simulation works fine for 64 cores but when we run it on 128 and 256, the particles seem to fly out or seem to be get deleted somehow.
I hope someone could give me an insight about this.

I have attached the in file, the only difference between the 3 being the number of processors.
64 cores -processors 16 2 2
128 cores -processors 32 2 2
256 cores -processors 64 2 2

Also attached is the final image of the simulation.

Hello.

I am trying to simulate granular flow using LIGGGHTS.

In my simulated scenario, almost all particles are concentrated in the lower right corner of the boundary region, so the load would be not balanced if we simply divided the domain equally. Therefore, we need to modify the divided domain according to the distribution of the particles, e.g., allocating more worker processes in the lower right corner.

Greetings, i recently finished a simulation in LIGGGHTS 3.6, but when i try to post processing the information using "lpp", the process freezes. I use the cpunum command in order to reduce the cpu cores, but it still freezes and no error message is shown. I'm still waiting for restarting of the process, but it has passed more than 7 hours and nothing happen.

I add the lines from my console.

Hello to everyone

Is there a way to work with cuda processors to run a simulation in LIGGGHTS?. I have a Nvidia Geforce GTX 960.

Best regards.

Nicolás.

Dear liggghts users,

I want to set up a simulation with bonds (I am using liggghts-with-bonds) that has atoms with different sizes. I was not able to get different atoms with the „create_atoms“ command.

My idea was to first insert the atoms with the fix insert/pack command, let them settle and then create the bonds in order to have bonds and different sized atoms.