LIGGGHTS® - User Forum

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

I am trying to simulate a deformable particle and I was wondering what you have experienced as a good atom_style to use.

Because I thought that the atom_style bond or body (from Lammps) would suffice, but both appear to be non-existent in the Public version of Liggghts. At least, I thought that atom_style bond would, but when using I obtain the error message "ERROR: Invalid atom style (../atom.cpp:432)".

Hence, what would you think is a good atom_style to use for a deformable (donut like shaped) particle?

Hello,

I'm developing a transfer chute simulation wich has more than a million particles in the scenery, and is taken a lot of time for running.

It's a symmetric problem, so I would like to know if LIGGGHTS has a function like symmetry plane, or something like that.

Best regards!

I would like some help on how to visualize your mesh in paraview and how to manage the output file concerning the mesh from LIGGGHTS.

For my output files I always use the following type of commands:

# Concerning a Continuous Blending Machine (CBM)
dump dmp all custom 1000 post/dump*.CBM id type type x y z ix iy iz vx vy vz fx fy fz omegax omegay omegaz radius

1. Whenever am I trying to run simulation using the hooke/stiffness model with the code give below the particles are passing through the zwall which they shouldn't. Can anyone please clarify that what is wrong with this code?

2. Can I define new model instead of using the predefined model for granular contact ?

3. While using the absolute_damping off in hooke/stiffness model, Is it possible to change the given formula for gamma_n i.e. from given formula (gamma_n-specified)*(m_effective) to (gamma_n_specified)* (m_effective)^(0.5).