LIGGGHTS® - User Forum

Hi

I am trying a mulisphere break case.

In the LIGGGHTS Tutorials-public "multisphere_stone_restitution" example in.multisphere file, I add

"fix m6 all property/atom fz scalar yes no no 0.02"
before integrator, and change integrator to be

"fix integr all multisphere/break trigger_threshold 0.1 trigger_timeStep 0 trigger_fixName m6"

After type ./lmp_fedora -echo both < in.multisphere2, I get the ERROR of

I keep getting an error during bond creation:

creating bond btw atoms 1501 and 1503 (i has now 6 bonds) at step 1
creating bond btw atoms 1502 and 1501 (i has now 1 bonds) at step 1
creating bond btw atoms 1502 and 1503 (i has now 2 bonds) at step 1
creating bond btw atoms 1502 and 1504 (i has now 3 bonds) at step 1
ERROR: Internal fix bond/create error (../fix_bond_create_gran.cpp:465)

Hi All,

Attached is the insertion face stl and give embedded is a full script where I want to have coordination number of particles in a multiple particle size distribution system;

# Testing Script

atom_style sphere
atom_modify map array
boundary f f f
newton off

communicate multi vel yes

units si

region reg block -0.1 0.1 0. 0.40 -0.1 0.1 units box
create_box 3 reg

neighbor 0.03 multi
neigh_modify delay 0 every 1 check yes

# Material properties required for new pair styles

Hi ,
I am trying to set up a simulation with multiple spheres clumped together to form rod shape particle.
As I am still very new in LIGGGHTS, I am having dificulties in doing this simulation.

Can someone share example solved exactly as seen in LIGGGHTS Features > Non-spherical particles > Example - pouring a continuous stream of non-spherical particles, where can be seen particles made of 3 spheres stick together.

Thanks in advance.
Kashif

Hello,

Can I have an example of a simulation where both spheres and multispheres are used?
In particular I would like to specify more types of spheres (different diameters) and multispheres (different clusters).

I feel a bit lost when I have to specify the material properties of all the types.
Do I have to specify a set of types for spheres starting from 1 and another set of types starting again from 1?

Hi all.

I'm running a script where I have a mesh/surface shutter that is rotating counterclockwise from a starting angle. I want to unfix this mesh once it reaches a certain angle and I've been trying to think about the best way to do this in LIGGGHTS.

The best idea I had was to track the co-ordinate of a point on the mesh (i.e. a bottom corner, which is one of the co-ordinates I inputted to make the mesh) and use an if statement when this co-ordinate exceeds a certain value.

Hello,

I am having various problems while implementing SPH cases in LIGGGHTS. Firstly, I am not able to include .stl geometries into the fix wall/region/sph command as it does not accept a fix mesh/surface. I then converted the .stl into an ASCII VTK format and tried to introduce it as a region, which was successful. However, implementing this region in fix wall/region/sph is causing problems when it is an open geometry, such as a cylinder with one face open.

Hello, Everyone

I tried to use Washino/Capillary/Viscous in my simulations.
However, I got errors saying: the value of "maxLiquidContent" has to be 0~1.
I checked the cohesion_model_washino_capillary_viscous.h
Seems like the setting of "maxliqduicontent" is the same as "surfaceLiquidContentInitial", which is in unit of %.
Just want to confirm how do I correctly set the maxliquidcontent in this model? for example, should I type 5 for 5%, or 0.05 for 5%?
Many thanks!

Renge

hey guys, i have a similar problem.
Im trying to simulate an underwater slope with a given volume fraction. First I try to generate a normal box of particles and the delete the particles to generate the slope with a restart file.

this is my input data:

#Unterwasserboeschung

atom_style granular
atom_modify map array
boundary f f f
newton off

communicate single vel yes

units si
processors 2 2 1

It appears to be a huge inconvenience if 'fix massflow/mesh' cannot use 'delete_atoms' with 'fix multisphere', as the error shows below:

#########################################################################################
ERROR: Fix massflow/mesh (id massflow): can not use 'delete_atoms' with fix multisphere/* (../fix_massflow_mesh.cpp:304)
#########################################################################################