LIGGGHTS® - User Forum

Hi,

i have the common task to track the mixing status in my apparatus. For this i need to find the number of particles Type 1 and Type 2 in specific regions. Lets say i want to have cylinders and count the number of particles in them every 10000th time step and print the result to a file, How can i do that? Is there a way to do that in the input file?

Thanks and kind regards

hello everyone hope ur all well i am stuck on a problm i am trying to make a script to push or attract particles using an electrostatic field but i have a problme the same error keeps popping and i could not resolve the problm i know it is not a big problm for some of you but it is for me and i would apreciate any tips on how to improuve my script to reach my goal it is far from finnished thank you all

ERROR: Numeric index is out of bounds (../force.cpp:786)

#falling particles in electric field

Hello Team,

Greetings. I hope, you are all doing good. I'm working on homogeneous simple shear simulation using the following two methods.

I'm trying to use rRESPA with a fix, however without the fix_modify respa options in lammps I'm unsure how to set the loop to apply fix forces at. Does anyone have any experience with this in LIGGGHTS? I see many fixes, such as fix_efield have rRESPA infrastructure in their code.

Thanks,
Thomas Leps

Hello everyone, I want to obtain a densest sample with equal sized spheres. I am using radius expansion method，and there is a factor named alpha target，referring to the packing density after expansion(I guess)，and I want to know the maximum value of this factor that can be used,thanks.
Best regards.
Zhao

hello everyone i hope ur all doing well i am a new ligggths user i need help i want to add an electrostatic field to attract granuls or push them if possible with positive and negative voltage to make a granular separation i am trying to modify the chute wear scrit by adding efield command but it's not working getting the following error thank you all

atom_style hybrid charge granular
atom_modify map array
boundary f f f
newton off

communicate single vel yes

units si

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.