LIGGGHTS® - User Forum

Hi Everyone,

I wanted to compute atom properties and then dump them in a .vtk file. However, I cannot see them printed. Here are my commands:

compute ins all property/atom id type xs ys zs fx fy fz # Calculation of atom attributes
dump dmp all custom/vtk ${writeOutEvery} post_hl1_100kpa/dump*.superq.vtk c_ins

The error is " ERROR: Dump particle fix does not compute per-atom info (../dump_particle.cpp:594)"

If someone can help with this, I will be very grateful.

Sincerely,
Sounik

Hello,
I have a small cluster of computers that I would like to run DOEs on.
On my machine I call liggghts with the partition flag

mpirun -n 10 liggghts -in DOE.liggghts -partition 10x1

but when trying on the small cluster

mpirun -n 20 -hostfile my_hosts.txt liggghts -in DOE.liggghts 20x1

I get an error indicating that liggghts can not read my input file
(ERROR on proc 4: Cannot open input script DOE.liggghts (../lammps.cpp:442))

I've been simulating tensile tests of elastic materials to validate my model for some research I'm doing, however I'm finding that I get anisotropy in bond formation where I get layers that do not bond well, even with different seeds for bond formation and insert/pack random particle insertion.

Hello!,

I opened VTK files for sphere packing in Paraview, and applied Glyph filter. However, I can't adjust the theta and phi resolutions as in Sphere Source. How can I increase the resolution of the geometry? After saving as STL file, I found its resolution is very poor.

Hello everyone,

I have a case where particle sizes stretch across an order of magnitude. Do you have any strategies for realizing efficient contact detection in such a scenario? How do you size the bins for this kind of case?

Any input would be greatly appreciated!

Hello,
I am trying to create multi sphere parcels included 9 spheres. and I used the following command:
fix pts1 all particletemplate/multisphere 15485863 atom_type 1 density constant 2500 nspheres 9 ntry 1000000 spheres file data/stone1.multisphere scale 0.001 type 1
If I want to have 200 parcels, should I create manually 200 particle parameters (positions, radii) in the data/stone1.multisphere file?
is there any way to create 200 multishperes? because the shape of all them are similar.

Dear all
I am wondering if there is any way to calculate sphere particle's cumulative rotation. is it possible to dump particle's rotation through run? if the answer is no, how it can be done by postprocessing?
any help is appreciated.

Hello there!

I hope you can help me with a situation. I have a particle template with diferent sizes, then I insert certian mass of these particles into a container randomly. The container sort the sizes by a threshold, so sizes below the threshold leaves the container. I want to re-insert the particles that leaves the container using the same feeder that insert the original template.

What should I do?

If you need more information, please ask.

Thanks for your time.

Greetings

EDIT:

Here I attach a pic to explain what I want to do

Hello all.
I want to simulate a granular flow behind a gate and after a time the gate have been released (like a dam break).
I could not insert particle once... could any body help me? The total mass is 0.8 kg and particles radius is 0.8 mm.
atom_style granular
atom_modify map array
boundary m m m
newton off

communicate single vel yes

units si

region reg block -0.5 0.5 -0.2 0.2 -0.2 0.35 units box
create_box 1 reg

neighbor 0.01 bin
neigh_modify delay 0

#Material properties required for new pair styles

Hi,

I have a problem when trying to model atoms which are 100um in diameter. When the atom size is 100um in diameter, the atoms keep lost during the process, and it won't happen when atom size is larger than 0.001m. Could anyone explain why it happen and how to fix it? I tried to change the units to cgs, but it did not work...

atom_style granular
atom_modify map array
boundary f f f
newton off

communicate single vel yes

units si

region reg block -0.05 0.05 -0.05 0.05 0. 0.15 units box
create_box 1 reg