LIGGGHTS® - User Forum

Hello Everyone,

I have a question about the fix wall/gran command - I am using the ver. 3.3.1. of LIGGGHTS.

I am using boundary p p f and I want three walls, two bounding the simulation and one in the middle (to create two layers)

fix zwallsdown all wall/gran model hertz tangential history primitive type 1 zplane ${bottom_plane}
fix zwallsmid all wall/gran model hertz tangential history primitive type 1 zplane ${mid_plane}
fix zwallsup all wall/gran model hertz tangential history primitive type 1 zplane ${upper_plane}

Hello everybody,
I am a new user of LIGGGHTS and I am running simulations by inserting a particle packing in a fixed volume:

insert/pack ... particles_in_region 100000

Of course, as I expect, I have a "less inserted than required" since less than 100000 particles are needed to fill the volume.

Dear users and developers,

Hi,
(SEE EDIT)

*****UPDATE****
- I have this simulation with a capillary model for cohesion.
- The simulation run without any problem on 32 cores.
- If I add a compute pair/gran/local, a Segmentation Fault happens for 32 cores depending on the mapping of the processors!
- No ERROR for 8, 16 cores or single core.
- If I change the maxSeparationDistanceRatio to 2.0 I have the error for single core!

Do you think there is a bug?
********

*****ORIGINAL POST****

In the manual:

radius values = random_style param1 (param2)
random_style = 'constant' or 'uniform number' or 'uniform mass' or 'gaussian number'

If I understand it right one can specify a low and high radius value and the pts interpolates uniform by mass. This would excactly what I need for my sieving analysis. But the codes stops with:
"ERROR: mass distribution not implemented for uniform (c:\liggghts3-bonds\liggghts-with-bonds\src\probability_distribution.h:170)"

Hi all!

I try to set the velocity and the angular momentum to zero at a certain point in my simulation and I want to use the velocity command.
For the velocity it works fine, but for the angular momentum I couldn't get it working.

Hi all,

I would like to know which is the algorithm behind the cluster/atom compute. Is anyone aware of that? Any reference?

Thank you!

Giuseppe

Hi all,

I am new to LIGGGHTS. After modifying the .stl file, I am getting the following error just after the code executes the fix command:

"fix cad1 all mesh/surface file screw.stl type 2 scale 1.0 curvature 1e-05
ERROR: Input line quote not followed by whitespace"

My script was working fine just with the old STL. Also, there is no problem in the new STL, as I used that in my earlier scripts.

Any ideas on what might be the reason behind this??

Thanks & Regards,
Aashish

I am generating the particles in box and let them settle down. Once the particle settle down, I unfix the gravity earlier defined and using fix/freeze comand to stick the particle to the base so that I can have bumpy base. Now I tilt the gravity to 25 degree but freeze layer is also flowing Can any one please tell what's wrong with the my code?
#Simple chute wear test

atom_style granular
atom_modify map array
boundary p p f
newton off

communicate single vel yes

units si

region reg block 0.0 0.1 0.0 0.1 0.0 0.15 units box

Hi,

When I want to create a particle at a desired location, an error is encountered.

create_atoms 1 single ${x1} ${y1} ${z1} units box, where x1, y1 and z1 are variables.
ERROR: Variable for set command is invalid style

create_atoms 1 single v_x1 v_y1 v_z1 units box
ERROR: Expected floating point parameter in input script or data file.

I also check the value of the variables by print.

print "The x1 is ${x1}"
The x1 is -0.0035

print "The y1 is ${y1}"
The y1 is 0