LIGGGHTS® - User Forum

Dear all,

I am trying to grow particles which works fine on one core but my simulation crashes whenever I try to run it on multiple cores.
I have tried out a couple of things and I am pretty much certain that the "fix adapt" command is causing this issue. I attached the script("growth") the stl file ("quadr")and the error message("error").

I am using a 4 core processor and running other simulations on my computer worked just fine...

Hi,

I have problems with the overlapcheck using liggghts 3.3.1. I would like to get particles without any force or velocity, but when I'm creating the particles they overlap and have a big kinetic energy. I use this command:

fix ins5 nve_group insert/pack seed ${seed} distributiontemplate pdd5 maxattempt 200 insert_every once overlapcheck yes all_in yes vel constant 0. 0. 0. region pi particles_in_region ${nliggghts_CB}

I attached my code. Maybe someone has an idea what's wrong.

Regards,
Laura

Dear all,

I want to ask a question about the times of RUN command. In most cases, we set the determined timesteps for RUN command, e.g. run 400000. Would it be possible that we set a condition until which the code will stop (e.g. run until c_force > 1000)? Could someone give me some clues about how to code this? Many thanks.

Regrads,
Zheng

Hi Guys,

Can you please advise me how I can exert the force on mesh elements?

Regards
Matt

Dear all,

I am facing a problem about saving the maximum of contact force.
I first get the pair-force with:

compute fc all pair/gran/local force
variable fmag atom sqrt(c_fc[1]^2+c_fc[2]^2+c_fc[3]^2)
compute maxfmag all reduce max v_fmag
variable maxcm equal c_maxfmag

There seems no mistakes while operating the above code, however, when I tried to output the result using:

fix data_max all print 10000 "The maximum of contact force = ${maxcm}" file data.txt

Hi guys!

I'm planning to assign material properties ( density, charge, youngs modulus etc.) to the meshes so that meshes can interact with the particle.

Eventually, I want my meshes to have Coulomb force and contact force with the particles.

1. If I use 'fix cad all mesh/surface file mesh.stl type 1' then imported mesh have the material property of atom type 1?

2. And if I want to assign material property different from the particle, then how can I assign it?

Dear all,

I have output the vtk. files of force chain and applied them in Paraview using the following two commmands:

compute cpgl all pair/gran/local pos vel force force_normal
dump dmp2 all local/gran/vtk 100 post/forcechain*.vtk cpgl

Dear
I am using the ubuntu that brings window 10 and I want to load LIGGGHTS, Ubuntu works fine but only in terminals. Someone has some procedure to load LIGGGHTS in this environment.
I'm new to this from loading the program.
Thank you
Alejandro

Hi,
I'm trying to superpose two move/mesh rotate commands. The application is like a robot arm with two parts and the rotation axis of the second part changes with the movement of the first part.
The manual says, that for style rotate, the origin of the rotation axis would be in local reference, if there is a move command before. I think, however, that the vector of the rotation axis always remains in the same direction. Is this correct or is there a way to change the vector of rotation axis, according to a move / mesh command before it?