LIGGGHTS® - User Forum

Hello All,

I have a simple shear case in which fix deform is used to shear the box. Using and not using fix momentum in all three directions did not have any effect on the final results.

When I include the gravity in y -direction for the above shearing case, is it correct to use fix momentum in y-direction also?

Also, could you please let me know when should one "use fix momentum and not" in a CFDEM simulation?

Thank you,
Jagan Mohan.

make[1]: *** No rule to make target '/usr/include/x86_64-linux-gnu/bits/libc-header-start.h', needed by 'compute_erotate.o'. Stop.

Hi ,
I am new in LIGGGHTS. I have tried melting of Nanoparticles in LAMMPS and would like to try it in LIGGGHTS.
I am trying to simulate multi material particles and their melting.
I am not sure how to do it, or in other words which sample case should be ideal to start with. Any Suggestion is appreciated.

Thanks

Nik

I'm inserting superquadric particles in a closed box. I want to achieve different volume fractions samples.

First, I tried insert/stream command but I couldn't control volume fraction with it.

Second, I tried insert/pack and insert/region/rate but only low volume fraction can be achieved with both methods even with very high maxattempt values.

Hi Everyone,

I'm pretty new to liggghts and having trouble on understanding and finding out some of the terms such as what is KinEng and rke in the terminal or liggghts log? (where can i find this info?)

I'm currently building DEM granular model with lattice model. and turns out that for some reason the KinEng & rke return as -Nan. during the run.

It is suspected that due to overlapping integration between lattice section and "fix integr all nve/sphere" (line64).

Please help

thank you in advance

code:

Hi all !

I am a new LIGGGHTS user and followed EngineerDo's tutorial for the silo particle dimension (https://www.youtube.com/watch?v=bCfCpjNuSVQ).

I used his code and tried to modify it for my problem, i.e. the generation of a powder bed particle for Selective Laser Melting. I created my substrate, which consists of a rectangular box of 0.5x0.3x0.3 (L,w,h, all in mm), and a blade which should spread the particles on the substrate after they fall from the insertion face.

Hi All, I an using insert/stream to insert particles from a plane. I have tried inserting particles of different sizes in turn by using two insert/stream, namely inserting one size first, unfixing ins, and then the other ins, it didn't work. Can anyone give any advice?

Does anyone know how per multisphere quantities can be manipulated like per atom quantities? For example, with a mixture of spheres, I could do the following computation if I would like to:

variable velx atom vx
variable vely atom vy
variable sqvel atom sqrt(v_velx^2+v_vely^2)
compute vel all reduce ave v_sqvel

Hi,
I am new to LIGGGHTS and have been having trouble finding information on how quaternions are calculated.

This is the second time to ask this question since nobody answered the first and I really need an answer for this issue!

I'm trying to make a triaxial compression test in two scripts. First, generating particles using insert/stream in a cubic region then unfix all walls and save a restart file. Second, fix new servo walls and apply equal pressure from all walls except the base wall and after reaching the target confining pressure, I only increase the pressure of the upper wall to apply vertical compression on the sample. I use kp = 1, ki = 0, kd = 1e-6.