LIGGGHTS® - User Forum

Hi, everyone,

I am working on mixing of granular particles in a cylindrical bladed mixer. I want to create force chain network as like given in the attached picture.
would you help me to create the contact force chain structure like that? how to get output from liggghts to built this structure.
thanks in advance

Hello,

I am trying to simulate the angle of repose of alumina. A picture of the simulation I am performing can be seen in the Figure attached. It is a funnel unloading alumina directly in the floor, and after a certain amount it should stabilize and one could get the angle of repose.

However, I am facing a weird behavior. After stop inserting particles, the pile of alumina (which until this point seems to have a correct angle of repose) suffers some instability and collapses a little bit, affecting the angle of repose.

Hi,

I'm new to LIGGGHTS and was trying to run the in.movingMeshGran example on the terminal. The input was "mpirun -np 4 lmp_auto -echo both< in.movingMeshGran" which produced the following output: "in.movingMeshGran: No such file or directory"

What may I be doing wrong? I'm certain the file exists and can open it using TextEdit on Mac to view it.

Thanks
C CH

Hi all,

I am currently trying to use Fix external pf/array command.

I am using a Python interface to LIGGGHTS-Public as the external driver. The Python Interface is build and wrapped according to the official documentation:
https://www.cfdem.com/media/DEM/docu/Section_python.html

Hi All,

I want to know id of an atom during computation for that I am using property/atom command like this

compute ID impactor property/atom id
variable aID equal c_ID[1]

here impactor group only has one atom. And I access this with v_aID. But it throws an error :

ERROR: Compute used in variable between runs is not current. Use the update_on_run_end option for computes to avoid this.

After following this error message I change the compute command

compute ID impactor property/atom update_on_run_end yes id

Hi Christoph,

Can you please tell me what this error is?

WARNING: New thermo_style command, previous thermo_modify settings will be lost (../output.cpp:725)
ERROR: Invalid keyword in thermo_style custom command (../thermo.cpp:819)

Hi,
I'm trying to implement a liquid bridge model and wanted to use the available washino model in LIGGGHTS as starting point. So I just renamed the file:
cohesion_model_washino_capillary_viscous.h
cohesion_model_lqb.h

and within the file adjusted accordingly the name. Also for the identifier, gave it a value of 9:
#ifdef COHESION_MODEL
COHESION_MODEL(COHESION_LQB,lqb,9)
#else

When I try to compile the code I get error regarding redefinition of the model parameters. E.g.

Hey all,

I have got a 2D-array of different values for a force field depending on the region from another program (matlab) in a txt.file (other files are also easily possible).
I want to add these values via the addforce command to the particles in my simulation.
Depending on the position of each particle, it should give me an unique forcevector.

Hi all,

I have try to use the 'fix mesh/surface/stress/servo' to apply confining pressure on each sides of a cubic box. (100mm*100mm*100mm)

I want to apply 200kPa confining pressure on each sides with the following command. Take the left side as an example

fix zservo2 all mesh/surface/stress/servo file meshes/rwall4.stl type 1 com 0. 0. 0. ctrlPV force axis 1. 0. 0. target_val 2000 vel_max 100. kp 1e-2. ki 0. kd 0. #left

Hi guys,
I am currently using Red hat .
I tries to compile LIGGGHTS(3.5.0) by using make fedora but error occurs as follows :

/usr/bin/ld: cannot find -l-lsundials_cvode
collect2: ld returned 1 exit status
make[1]: *** [../lmp_fedora] Error 1
make[1]: Leaving directory `/share/apps/LIGGGHTS-PUBLIC-master/src/Obj_fedora'
make: *** [fedora] Error 2

so I tried make spirit instead of make fedora but it gets the same error :