LIGGGHTS® - User Forum

Hello!

I've been running a simulation with timestep 2.5e-7 and there were no warning messages. Once my computer shut down so I had to restart the simulation and used read_dump command with 'add' set to 'yes' for this. After I have restarted it, there were following messages:

WARNING: time-step is 397.197160 % of rayleigh time (../fix_check_timestep_gran.cpp:200)
WARNING: time-step is 63.994760 % of hertz time (../fix_check_timestep_gran.cpp:208)

Hi everyone,

I am trying to compute the torque on all the meshes of a given stl. In LIGGGHTS, I got the following module:
mesh module stress

I used it in script in the following way:
fix st all mesh/surface/stress file Frustum-1.stl type 1 wear

But I am unable to get the required output. I tried outputting it using thermo_style custom. But what I obtain is a series of just 9 zeros coming in rows. The values cannot be 0 actually. Moreover, it does not give the meshwise values.

Hi all,

I am encountering a problem here where my particles are disappearing and not behaving normally.
I am simulating a closed-end cone that filled with 100 micrometer diameter particles.
I notice that when I bigger diameter particle (smallest I can do is 150 micrometer diameter), the simulation still works and doesn't behave strange. So the problem only occurs on diameter less than 150 micrometer.
Is there anybody that can help me with this?

I also attach the .avi file but can only upload it in .txt, you can change the extension.

Hello everyone.

What is the best way to start learning liggghts as there are a lot of commands in the input script, so can you give some tips as to how to begin learning?

Hello everyone,

I am wondering why my simulation is showing spheres that are "floating". Does this happen due to the property of materials? In the screen shot, particles floating in "air" for multiple time steps and not moving much after particle collision. It didn't happen with my other practice scripts.

I have attached my script, could someone critique it please? This is my first time really exploring liggghts so my script is messy and I would really appreciate someone pointing out errors and tips.

I have attached a screenshot of what paraview is showing.

Hello!

I am trying to simulate about 7 million particles with size ranging from 0.0003175 m to 0.0031 m. During the simulation I have received the following error:

Memory usage per processor = 356.933 Mbytes
Step Atoms KinEng CPU
66000 1860696 980.5158 0
INFO: Particle insertion ins: inserted 1019560 particle templates (mass 6.060482e+01) at step 66667
- a total of 2880256 particle templates (mass 1.712086e+02) inserted so far.

SOLVED!

I wonder is there any limitation to the .stl-file sizes used for a simulation in Liggghts? I have two stls with around 80 MB each and my simulation crashes when i try to load them..

EDIT: I attached a picture. It just crashes and does not give any hint on what the reason is.. So is there a limit to files sizes maybe?

Hi All,

I am running cfdemSolverIB with a cyclic boundary but particle doesn't reappear after passing one cyclic side. Is there any suggestion to solve this problem?

best,
Arghavn