LIGGGHTS® - User Forum

I am pretty new to LIGGGHTS and DEM simulations. I am trying to model granular flow of particles with cohesion force between them. The flow should be like - they start from a point and gather mass progressively in a fan‐like shape as they slide down the slope with some wet/slurry effect between the particles along with cohesion force. I have started looking at the chute wear example by altering the Hertz cohesion coefficient to 1 to have cohesion effect between the particles.

Has anyone done any such kind of simulation using LIGGGHTs before?

Hi,
I encountered an error when doing a simulation based on a modified code of LIGGGHTS which says: Length not sufficient for variable cohesionEnergyDensity. May anybody tell me what problem may it because and in which src document may I find it?

Thanks!

Jerry Wang

Hi,
I created a "particle wall" by using "fix rigid" and tried to let this "particle wall" to compress the particles filled in a cylinder under gravity (so there are totally three materials: filled particles, "particle wall", cylinder wall), but i got very strange result. The "particle wall" pass through the filled particles and even the cylinder (if the timestep is many enough). It appeared that this "particle wall" didn't compress the particles filled in the cylinder at all. Does anyone have any idea about this problem?

Thanks
Xuetao

Hi,
I can not import more than one CAD in new version of LIGGGHT. If I import more than one CAD then it prompts this:

.....
........
Importing STL file 'stl/cyl2p5z.stl'
Solid body detected in STL file
Growing STL input arrays
Growing STL input arrays
End of solid body detected in STL file.
WARNING: STL face normals were not normalized, normalizing
Mesh calculations running. This may take a while...finished!

Import of 14760 triangles completed successfully!

Importing STL file 'stl/spz.stl'
Solid body detected in STL file
End of solid body detected in STL file.

Hi all,
is there any complete tutorial to install LIGGGHTS on Mac OS X (Snow Leopard)?
I extremely need help!!!

Vincenzo

Hi,

I run a simulation where it exists various contacts between spheres and a mesh (triangle). In my case, the stifnesses for these interactions is computed by the function FixWallGranHertzHistory::deriveContactModelParams().
However I would like to know where this function for the FixWallGranHertzHistory is called in the code ?

Regards
JF

Hello,
i am trying to simulate a shear test. In the simulation, i need to apply a constant force on the coverwall. does anyone know how to do it?

Thanks
Ada

Hi Christoph,

When I check the package status, the Granular package was not installed and the messages appeared as follows. Please give me some advice to handle it.

Thanks.
Jianwen

username@ubuntu:~/liggghts_1p3p1/src$ make package-status
Installed YES: package ASPHERE
Installed YES: package CLASS2
Installed YES: package COLLOID
Installed NO: package DIPOLE
Installed NO: package DSMC
Installed NO: package GPU
test: 18: ../angle.cpp: unexpected operator
test: 18: ../add_fix_property.h: unexpected operator
Installed NO: package GRANULAR
Installed YES: package KSPACE

Hi Christoph,

I have noticed that the GPULAMMPS (LAMMPS Cuda) has already allowed the gran/hooke/cuda since Feb 3, 2011. And some guys still work on the Hertz contact model.

Is is possible to get this gpu-acceleration for hooke in LIGGGHTS?

Best,
Tong

Hi Christoph,

I want to ask about what rolling friction model is used in LIGGGHTS. And what is the typical value of rolling friction coefficient for sand?

Thanks in advance!

Best,
Tong