LIGGGHTS® - User Forum

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

Hi everyone,

I am trying to simulate an assembly of bonded particles and using the software LIGGGHTS_Flexible_Fibers by mshramm. The script of my simple insertion simulation is:

# Constant settings
atom_style hybrid granular bond/gran n_bondtypes 1 bonds_per_atom 6
atom_modify map array
boundary f f f # will change to f f f boundary to save time
newton off
#echo both
communicate single vel yes
units si

region reg block -0.05 0.05 -0.035 0.035 0.0 0.025 units box
create_box 2 reg

Hello,

I am running a simulation about granular flow with around 20,000 particles, among which there is one special particle (called "intruder"). Right now, I would like to change the shape of the "intruder" from sphere to cylinder (superquadric), while keeping the shape of other particles as spheres. So how could I do it?

My current "intruder" particle creating code are like:

create_atoms 2 single ${xintr} ${yintr} ${zintr}
group intruder type 2
set group intruder diameter ${dl} density ${rho}

Thanks!