LIGGGHTS® - User Forum

Hi Chris,
Could you give hints about the calculation of neighbors in LIGGGHTS?
I am using the following commands in the programme.
lattice fcc 0.0013
neighbor 0.00125 bin

It is creating
Total # of neighbors = 48418
Ave neighs/atom = 24.209
Neighbor list builds = 27

Hi

i need create 2 atoms with different youngsModulus parametr.

i try this:

fix m1 all property/global youngsModulus peratomtype 5.e7 5.e6

create_atoms 1 single 0.0 0.0 10.0
set atom 1 density 2000 diameter 2.0

create_atoms 2 single 5 0.0 10.0
set atom 2 density 2000 diameter 2.0

So i get that ERROR: Invalid atom type in create_atoms command
What's wrong?

Thanks
jikra

Hi, all

I just got an error with the 'fix' when running the LIGGGHTS examples:

fix m1 all property/global youngsModulus peratomtype 5.e6
ERROR: Invalid fix style

It seems the property/global is a LIGGGHTS style for the 'fix'.
The LAMMPS examples were done well, without any error, perhaps the LIGGGHTS was not invoked properly??

Any help is appreciated.

Hi everyone,

I'm trying to set up a simulation with 3 spheres clumped together, 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 glued together.

I'm exploring some possibilities to do a modification of this study http://www.nt.ntnu.no/users/skoge/prost/proceedings/ecce6_sep07/upload/1... by simulating a packed bed with non-spherical particle as my PhD study. My idea is starting with 3 spheres glued and then move on with different particle geometries.

Hi all,

I have so far been running LIGGGHTS with more-or-less "large" particles (mm/cm), but now want to move towards the size that interests me, around ~1 µm or so. However, if I try to use fix particletemplate/sphere and fix particledistribution/discrete to generate small particles I get an error which seems to arise from a hard-coded limit:

if(volume_expect < 1e-12) error->all("Fix template/sphere: Volume expectancy too small");

in fix_template_sphere.cpp.

Hi. I want to use mesh/tet and insert/pack features.
I use in.insert_pack example file as basic for my simulation.
But I get an error when I use own insertion region geometry file instead of test.vtk:

LIGGGHTS 1.4.1 based on lammps-10Mar10
Created orthogonal box = (-1 -1 -1) to (1 6 2)
1 by 4 by 1 processor grid
Fix particledistribution/discrete (id pdd1): distribution based on mass%:
pts1: d=5.000000e-02 (max. bounding sphere) mass%=30.000000%
pts2: d=3.000000e-02 (max. bounding sphere) mass%=70.000000%

Hi all,

I had a look at the gran/hook/history/simple pair_style today. I thought that this pair_style should make you able to directly set the values for kn, kt, gamman and gammat depending on the contact-partners. So I was wondering why the values for the damping coefficients (gamman and gammat) are multiplied by meff. The same modification is done for wall-contacts.

I think that should be changed otherwise you have to take the multiplications into account when you set the values in the input-script.

Regards,

Yansan

Is it possible to use a gaussian distribution of radii for the particletemplate/sphere command? The documentation says it is possible but I am getting the following error:

ERROR: Random style gaussian not available for radius

My pertinent code is:
fix pts1 all particletemplate/sphere 1 atom_type 1 density constant 2500 radius gaussian 0.0003 0.00005
fix pdd1 all particledistribution/discrete 1. 1 pts1 1.0

Thanks,
Will

Hi all,

I have been playing with aggregated particles using a hybrid granular/molecular pair style, and am now introducing heat flow into the simulation. In the current implementation if I exclude the aggregates from neighbor calculations, there is no heat flow between member particles (this, of course, makes sense!). If I remove this exclusion, then heat does indeed flow, but at a rate determined by the thermal properties and the initial overlap when the aggregates are created (i.e. determining the contact area).

I would prefer either to be able to either:

I have an idea about vizing the superquadrics using paraview.
first, creat a superquadric source;
then, read your vtk files including particles postions;
the last, use glyph with custom sources. The following image shows what I have done.

Chen