LIGGGHTS® - User Forum

Dear Sir/Madam

I am a beginner to LIGGGHTS. I have installed ICC, OpenMpi, FFTW, PARAVIEW and LIGGGHTS in my Ubuntu 10.04 Lucid platform.
Please guide me to get started with LIGGGHTS. How should I proceed. At some beginners tutorial should be provided.

Please help.

Rahul Kumar Soni
Indian School of Mines
India
http://sites.google.com/site/ismrahulsoni

Hi, Christoph, i have a question about the difference of pair_style in LIGGGHTS and LAMMPS. As LIGGGHTS manula discribed, the stiffness and damping coefficients in LAMMPS are now derived from the material propeties (e.g. Young's modulus, poisson ratio).

Hi,
Is it possible dump forces on stl?
I'd like to save a dump file to then create with pizza a surface vtk file with force field (like a patch).

Thanks for any reply

Andrea

Hi,
I'm new with LIGGGHTS. I tried the tutorials and they are very good but I found only granulars that move from an inlet to grond (or to outlet).
How can I set instead fixed granular on a plane like a ground?

Thanks for any help

Andrea

Hi all,

In the discrete element method, the normal contact between two spheres i and j has the same direction than the n-axis (in the local reference (n,s,t)).Thus, it is possible to compute the angular orientation of the particle "i" following the s-axis and t-axis (tethai_s and thetai_t) in the global reference (x,y,z).

To compute tethai_s and thetai_t in the global reference (x,y,z), I do:

thetai_1 = omega[i][0] * dt;

thetai_2 = omega[i][1] * dt;

thetai_3 = omega[i][2] * dt;

Hi all,

I am trying to restart a heat transfer simulation. I failed and thus I created a smaller problem, where I have the same problem, using the example heatTransfer_2. Please find two input scripts for liggghts below: in.heatTransfer and in.restart. in.heatTransfer writes a restart file after it is done integrating and then in.restart reads the restart file. Visualizing the output with paraview showed that the temperature is not read from the restart file.

Could you tell me, what I am doing wrong?

Hi Christoph,

I saw that the commands : read_restart and restart can save and reload a simulation.
However, I would want to know if these commands also save and reload the values held by the array "shear" (contact history).

Regards
JF

Hey everybody,

after installing Liggghts on Fedora 14 the following error message occurs when I try to start liggghts:

liggghts: error while loading shared libraries: libmpi_cxx.so.0: cannot open shared object file: No such file or directory

I have installed the newest version of openmpi and the mentioned file can be found in /usr/lib/openmpi/lib

I attach a screenshot.

Thanks for your help!
Andre

Hi all,

I have two questions:

Do you know how should I use the command (fix addforce) to push a group of spheres ?
Because this command only works during an energy minimization, but I don't understand the minimize command (it is a specific command for atomic simulation).

During a tensile test on a granular sample, it is possible that some spheres are outside the box initially defined. Do I need to change the size of the box during the simulation or there will be no errors ?

Regards
JF

Hi, all

I am thinking and finding if there is a rotation viscosity(damping) or rotation constraint command in LIGGGHTS, which may allow realistic description of granular flow behavior.

I have found a fix momentum command which allow me to zero angular momentum every several steps, but it is not what I want.

Any response from you will help! Thanks a lot!

Best,
Tong