LIGGGHTS® - User Forum

Hi,
I want to rotate a cylindrical mesh along y-axis. It is not rotating along axial direction but rorating some point outside the cylinder:

fix cad all mesh/gran/stressanalysis STL.stl 3 0.01 -40 -20 -50 90. 0. 0.
..
..

fix rotcad all move/mesh/gran rotate 0 0 0.0 0 1 0 0.5 cad

How to make it still( no translational motion), just rotating along axial direction?
Thanks for advising me,
Ram

Hello.
How can I enable / disable the friction during the simulation?
I want to generate an initial package without friction, then the friction enable and continue the simulation.
Thanks.

Hi,
fix pour/dev/packing can be used with STL file. I mean i put STL mesh in box and then apply this command for packing. Is it valid way of doing? I guess this command uses whole simulation box for inserting particles including STL.
Thanks,
Ram

Hi,
I want to pack particles of two different diameters (0.003 and 0.0034). Starting from lower values of diameters. how can I confirm that after growing radius the final form of packing consists of the required diameters?
Thanks for help,
R

Hi,
I am a newbie to Linux and LIGGGHTS. I'd appreciate if anyone can tell me how to upgrade LIGGGHTS from old 1.1.10 to the latest version. Thanks!

Lenard

Hi,
I'm having problems inserting particles.
I'm using pour/dev/packing command.
After few iterations they jump to +Z very quickly like rockets and all crash.
My file follows:

************************************************
atom_style granular
atom_modify map array
boundary m m m
newton off
communicate single vel yes
units si

region reg block -0.015 0.015 -0.015 0.015 -0.32 10 units box
create_box 1 reg
neighbor 0.0200 bin
neigh_modify delay 0

# Material properties required for new pair styles

Hey all,

I've modified the basic 'packing' example, to have 3 particle types with different properties (instead of 1 type) and i'm trying to generate a random packing of this system. (3 types of particles each having its own radius and density). I don't try to make them grow, so I removed the growing radius part commands.

Anyway, when I visualize the system with Paraview, I see that I only get one type of particles, all with the same size, instead of the specified distribution of particles as seen in my script.

Hi,
I have simulation box filled with particles, I want to move cluster of some particles in this box. To do so, i defined one spherical region and then apply following command:
....
....
region mySphere sphere .........
group myGroup region mySphere
fix 1 myRigid rigid group 1 myGroup
...
...

Then I want to move this as spherical body made of particle in the simulation box consists of other particles.
Is this right way of doing this? When i run the simulation then it prompts:

447 atoms in group myGroup
ERROR: One or zero atoms in rigid body

Hi,
I'm trying LIGGGHTS in parallel. For example:
mpirun -np 8 lmp_openmpi < in.case
When it starts it prints:
1 by 1 by 8 processor grid
The problems is that sometime it works well, sometime it crashes with this error:
ERROR on proc 0: Failed to allocate -1738615408 bytes for array neigh:binhead

For example it works well with:
communicate multi vel yes
units si
neighbor 0.001 bin
neigh_modify delay 0
variable radius1 equal 0.005 # m

It doesn't work with:
communicate multi vel yes

Hi,
I get error when I run simulation from restart file, the error message is :

......
ERROR: Could not locate a fix/property storing value(s) for coefficientRollingFriction

However, when I run simulation without MPI then it works fine (with restart).

Thanks,
Ram