LIGGGHTS® - User Forum

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

Hello, experienced LIGGGHTS users,

Hello everybody, I am newbie in Liggghts. I am working on Particle insertation. My code failed after certain points. I couldn't figure out what to do:

variable dia1 equal 6
variable dia2 equal 2
variable rad1 equal ${dia1}/2
variable rad2 equal ${dia2}/2

variable startPercent equal 0.8

variable rad1_start equal ${rad1}*${startPercent}
variable rad2_start equal ${rad2}*${startPercent}

Hello,
I am trying to calculate the local void fraction in a bed having motion. Can anyone help me to understand how can I calculate the voidage in a selected region? Is it possible to calculate void fraction during post processing in paraview, if the simulation has been already done without dumping the mass or volume of the particles in the selected region? (I am using only DEM not CFDEM coupling).

Thanks and Regards,
Aks