LIGGGHTS® - User Forum

Hello,

I used compute pair/gran/local in order to find the contact area between two superquadrics. The output gives me 260 mm^2 while the diameter of the particles is 11 mm. The contact is edge-face, so basically this small overlap between face and edge, according to the output, produced the contact area more than twice the face-to-face total contact between the particles.

The question is what does "contactArea" exactly represent? What are the possible reasons why the contactArea found is so large?

Thanks everybody for Your replies in advance!

Hello guys,
Recently I am having a problem in particle insertion in drum.

I don't have problem with small size of particles with small drum. However, I am trying to use a bigger drum with width 2m and diameter 6m (si unit).
For bigger geometry I am trying to insert two types of particles with 1 m and 0.8 m. Whenever I increased the particles size, it doesn't increase the required number of particles in insertion. Instead it just insert 10, or 12 particles. I gues it is trying to control some of the calculation like fill mass rate or insertion.

Hello,
I am running a simulation that needs a hertzian contact force, as well as a SJKR cohesion force and a capillary cohesion force. I cannot get both cohesion forces to work in the same simulation. This is the command I am using.

pair_style hybrid/overlay gran model hertz tangential history cohesion sjkr cohesion easo/capillary/viscous
pair_coeff * *

And I am receiving this error:

ERROR: Unknown argument or wrong keyword order: 'cohesion' (../pair_gran_base.h:129)

Any help would be great thank you!

I am looking into how I would go about modifying an existing contact model to include charge conduction of particles through contact. I have to say my C++ skills aren't amazing but I have a fair bit of experience with programming in other languages so I understand how code is set up and run. My confusion comes from understanding where I would have to implement this code in order to allow for charge to be transferred when particles collide with each other and where I would put the calculations that are referred to during this interaction.

Hi everyone,

I faced an error when I try to push down (like hydrogel_multicontact tutorial) my particles.
When the number of particles are small the error not occured, but I have to increase the number of particles.

Thank you for your attention!

Here is the output. I cannot figureout the meaning of sidata.deltan.

Hello everyone,

i am trying to make a unixal compression stress test using ligggths and i get below error when i am running my script.Does anyone has any idea to how to fix below error:
The servo-wall requires a contact model. Therefore, it has to be used for a fix wall/gran too

my code is as below:

#### Writen for LIGGGHTS ritchi with bond ##########################################################

Hello LIGGGHTS forum,

I am still confused about deciding proper grain kinematics for my simulation. Could I get some help?

I am using three different types of particles with radius 0.03, 0.02 and 0.01 (in si unit) for a drum like sagmil simulation (for test simulation only).
Currently I am defining poision ratio = 0.3, cofficient of restiturion=0.6, sliding friction = 0.2, rolling friction = 0.1.
Density of grain is 2500 kg/m3, fillmass = 120 kg.

Hi every one

i am planning to compress a box with inserting a topwall and with below command put pressure on a stl wall wit 10 N force.however i get below error:

Reading STL file '3by3_Plate.stl' (mesh processing step 1/3)
ERROR on proc 0: Illegal situation in MultiNodeMesh::registerMove (../multi_node_mesh_I.h:373)

Here is my script:

#### ##########################################################

Hello,

I am running a simulation where I need to make a specific particle move with a specific linear velocity, and no rotation.

I use "fix move" command to set the linear velocity of the specific particle "intruder" as:

fix dragging intruder move linear ${vx} NULL NULL

But I don't know how to prevent the intruder from rotating on the basis of this. Do anyone know about this?

Thanks