LIGGGHTS® - User Forum

LIGGGHTS® related topics can be discussed here: discussion about models, installation, feature requests and general discussion

How to output mesh data (stress etc.) in the form of like particles?

Submitted by junelaue on Tue, 12/15/2015 - 14:09

I use the following command to output mesh data:
"dump dumpmesh all mesh/vtk 1000 post/dump*.vtk id stresscomponents mysurface";
I konw that VTK is good for paraview. But the data in VTK is not easy to use for quantitative analysis.
for granulars, I can output particles data using the following command, and it is easy to do post process for quantitative analysis.
"dump dmp all custom 1000 post/dump*.particles id type x y z vx vy vz fx fy fz";

Not a Number (nan) error with heat/gran

hunger's picture
Submitted by hunger on Thu, 12/10/2015 - 15:50

Hi all!

I have encountered the following problem with the energy equation in my simulation:

I am running the simulation with a constant particle temperature (for testing purposes). At a certain point, I get some "Not a Number" (nan) errors. The simulation goes on smoothly because the governing equations of movement are not affacted, it's just not possible to postprocess the temperature and heat transfer of the particles because the arrays are corrupted.

The thermo output looks like that when the error occurs:

Installing Voro++ package

Submitted by Joel Martis on Wed, 12/09/2015 - 15:30

Hi all.

I'm trying to install the voro++ package in order to enable computation of voronoi volumes of particles. However, the link for the source code provided on the LIGGGHTS documentation page seems to be broken (http://math.lbl.gov/voro++/download). Please tell me where I can find the source code.

Thanks.

Joel

Particles passing throug wall --> When rotating wall is close to stationary wall

Submitted by tuks123 on Wed, 12/09/2015 - 15:00

Hi,

I am facing problem of particles passing through wall. I am simulating case where, particles are rotated in a container using rotating impeller. This impeller (rotating wall) is very close (5mm) to the stationary wall of container. There are two types are particles (with 1.5mm diameter and with 7mm).

When impeller is rotated, particles pass through wall. Smaller particles escape through wall more than larger particles.

fix move INTEGRATION

Submitted by rob1 on Fri, 12/04/2015 - 17:49

Hello everybody,

I am inserting some atoms in a mesh/tet region and then fixing the body as rigid.
I would like to move this rigid body but, when using fix move, I get the warning:
"One or more atoms are time integrated more than once"
that gives unexpected results on the outputs I am calculating (e.g. forces on a mesh).

fix motion bottom_atoms move linear 0.01 0.0 0.0

Pression harmonic and run move two cads together

Vu Viet Dung's picture
Submitted by Vu Viet Dung on Fri, 12/04/2015 - 15:33

Hi all,
I wanna create a champs pressure harmonic on LIGGGHTS and define the pressure of a surface random. Can i do it?
I created some files cads 3D and input in LIGGGHTS, How can I do to move all CADs according to different ways (linair, wiggle...)?
Best regards!
Vu

A question about building LIGGGHTS-PUBLIC

Submitted by zhou_yu on Fri, 12/04/2015 - 12:42

I am gonna to use multisphere commands in LIGGGHTS-PUBLIC, since public version only support serial single processor. So whether it will caculate faster if I build LIGGGHTS-PUBLIC with dummy MPI library in STUBS, and does the compiler(g++,mpic++,icc) I choose have effect on caculating speed?

Mesh problems

Submitted by nicolasoviedoc on Thu, 12/03/2015 - 19:06

Greetings to all of you,

I was running a simulation in liggghts, and this message appears:

Mesh output: element id 100384 (line 702690) has 6 neighs, but only 5 expected

It appears several times but with other elements, and in the end, this error message appears:

ERROR: Mesh output: elements 164318 and 163297 (lines 1150228 and 1143081) are duplicate
ERROR on proc 5: Fix mesh: Bad mesh, cannot continue. You can try re-running with 'heal auto_remove_duplicates' (../surface_mesh_I.h:468)

what is the meaning of the 6 neighs, but only 5 expected?

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