LIGGGHTS® - User Forum

Hello everybody,

in LAMMPS documentation it is recommendet to use colloid and yukawa/colloid for DLVO potential.
I'm trying to use DLVO in LIGGGHTS (CFDEMcoupling) and now I stuck with the equations in colloid.
In LIGGGHTS only colloides are calculated, solvent is done by continuum. Does this mean the equations for colloid-solvent and solvent-solvent are not considered? Or is it computed with information transfered in the coupling?
Is there any hint, documentation or literature?

Thank you.

Henrik

Hi All,

I have a small question. Is the output results of LIGGGHTS simulation with same conditions differ? If say three or so same cases, same set-up, same conditions and same configuration are run, will there be any deviation?

Thank you.

I want to create cylinder(at coordinates 0, y,0) of radius 12.25 cm and o.74 cm height for region to insert particles. but its not creating at exact position.

Please help me. Code below

### Initialization

# Preliminaries
soft_particles yes
units cgs
atom_style sphere
boundary p p p
newton off
communicate single vel yes

# Domain
region reg block -1 1 -1 1 -1 1 units box
create_box 3 reg

### Setup

Hello everyone,

Right now I conducting a undrained triaxial test. The top and bottom walls are moving closer to compress the particles by "fix move/mesh" command and then the position of the side walls can be calculated. But I am confused on how to control the position of the side wall. I searched in the forum and found that in the old version of LIGGGHTS, the position of side walls can be controlled by "fix move/mesh/gran variable" command, but now this command doesn't exist anymore. Does anyone know how to control the side walls?

Thank you so much!

Dear LIGGGHTS users,
In LIGGGHTS for the integration of the velocity and the position we use a velocity Verlet scheme. This choice is motivated by the fact that we need to have a global conservation of the energy in our system. That’s why it is important to use a symplectic integration scheme.

Im getting these error. Please help me to solve this

Hello Friends

I am doing a small exercise to match the axial direction stress (sigma_zz) using the following two commands
(1) ave/time
(2) stress/atom

In order to calculate the axial stress from ave/time, perhaps I need to divide the z-direction force with piston area.
And from stress/atom command, I guess, will get directly the axial stress (sigma_zz) by using the following snippet

I'm setup a simulation where I'm pouring particles into a geometry to form a stack of particles. The particles are the agglomerating together with a cohesion model and I notice that the computational resources is increasing with increased number of particles (as one would expect).

For many of these particles they will not move anymore since they are just agglomerated together and have many contacts so I would like to skip the calculation on these particles and just freeze them instead such that Liggghts does not calculate the contact forces and they will then just act as a wall.

Hi Experts,

I can´t solve the task to write the contact forces between particles in a defiend region. I tried it with:

region comp block -0.075 0.075 0.0 0.075 0.015 0.03 units box

group comp_group region comp

compute Force comp-group pair/gran/local id pos force

Hi, I have a question, I know that in LIGGGHTS WITH BONDS there are two forms of fracture, my doubt is that it means that value of " $c " y {" rb "}
variable rp equal 0.015625 #Radio de la particula
variable d equal 2*${rp} #Diametro de la particula
variable rb equal 0.8*${rp} **************************** What happens physically if I increase this value?
variable I equal 0.25*PI*${rb}*${rb}*${rb}*${rb}
variable A equal PI*${rb}*${rb}
variable kn equal 2*$Y/$d # comportamiento del grano 3.2e8 tesis 1e10