LIGGGHTS® - User Forum

Hi,

I can already count total number of contacts as richti83 suggested here: https://www.cfdem.com/forums/particle-contacts-using-contactatom

I'm interested in counting collisions only between atoms of different types (types 1 and 2). Is it possible?

Hello everyone,
I think, the references at the documentation of "gran model hertz model" are not correct.

I spent a whole day to have a look at the references, before using them at my thesis.
I discovered, that the references are containing similar models, but no one of them, uses this model.

More over, there are some questionable things at the documentation like the bullet point
rmu = coefficient of rolling friction

But rmu is no where to be found ...

Hi everyone,

I am managing to implement the mesh/stress/servo command in my simulation. In my case, I would like to use the command to compress a packing by a small vertical force, i.e. I just want to flatten the top surface of the packing rather than strongly compress it. In other words, I just want to use a small force to compress the packing, thus I use CtrlPV force and target_val 0.003 as the parameters.

Hi,

Hello,

I'm starting a project, aiming to determine the shear forces on a conveyor belt. I have a geometry .igs and .dwg; How do I import these in a way the Liggghts recognize?

And how do I tell Liggghts that I want to calculate the force on the belt, after the particles come out of a chute?

It's my first work.

Hi All,

is there an easy way to implement a spherical particle, which has a high young's modulus on one halfspace and a small on the other halfspace (such as a Janus particle)? For example, could I define a point on the particle's surface, which follows the particle's streamline and the angular velocity?

Thanks for help.

Johannes

Hi,

I have been looking around with possible packages that could be applicable for my problem. After hours of google-fu, I arrived at LAMMPS and eventually here. Hence, I want to know if it could be possible to achieve what I am looking for with CFDEM.

Hi all,

Hi everyone,

I'm using the LIGGGHTS-WITH-BONDS package that was proposed by richti83. It works great even in CFDEM! However if I use periodic boundary all particles that exceed the boundary and reappear on the other side of my geometry lose all their bonds and are calculated as single unbounded particles from there on.
Am I doing something wrong or is it just a limitation of the current model?
Any suggestions or experiences?
Thx and regards

Hello to all of you

I have recently simulated the multisphere example that LIGGGHTS bring in the "examples" folder. After the post process, i use Paraview (version 4.1), but when i opened the VTK file, this error appears:

ERROR: In /build/buildd/paraview-4.1.0+dfsg+1/VTK/IO/Legacy/vtkDataReader.cxx, line 1919
vtkPolyDataReader (0x3518b50): Unsupported data type: 1

I think this is because of the version of Paraview, so my questions is, what version of Paraview support multispheres?

Thanks

Nicolás.

I am using the liggghts-with-bonds package to create bonds as described by cundall.
I can't find the syntax for fix bond_coeff
I copied the command somewhere and it works but i would like to understand what the arguments are in order to modify them. It seems that the second argument is the particle diameter which doesn't make any sense to me, because cundall always uses the smaller of both radiuses and I even found that command in the source code.