LIGGGHTS® - User Forum

Well, this is a basic test.
But, it does not work.
Here is the in file:

#particle distributions and insertion
fix pts1 all particletemplate/sphere 15485863 atom_type 1 density constant 8000 radius constant 0.005
fix pts2 all particletemplate/sphere 15485867 atom_type 1 density constant 8000 radius constant 0.0025
fix pts3 all particletemplate/sphere 15485867 atom_type 1 density constant 8000 radius constant 0.001

fix pdd1 all particledistribution/discrete/numberbased 32452843 3 pts1 0.3 pts2 0.5 pts3 0.2

Hi all,

I have some problems when trying to set a following symbolic link for LIGGGHTS as mentioned in the installation guideline. After running the "make fedora" command, I got "Obj_fedora" as a return in the /Home/LIGGGHTS-PUBLIC/src directory instead of "lmp_fedora. Can anyone help me with this? Appreciated for your help.

Hi

I am facing a challeng in visualising my simulation results properly in Paraview. I am only seing point particles instead of the full spherical shapes. As such all particles sizes visually look the same since they are points. May someone assist on how i can visualise the particles such that they are not points.

Thanks

I am trying to simulate a direct shear test that has 12 mesh walls each with 2 triangles. The upper and lower walls are used to compact the specimen, so their position and velocity change. I have two fix mesh/surface/stress/servo commands and ten fix mesh/surface/stress commands. I am trying to use a write_restart command after the compaction stage so I can restart more simulations without having to repeat the compaction process. How do I save the particle configuration as well as the mesh configuration and then load both of them into a new simulation?

hallo everyone,

Can anyone explain to me, why Fix heat/gran/conduction is maybe not valid for pair style hybrid/overlay?

"Fix heat/gran/conduction implementation may not be valid for pair style hybrid/overlay"

Best wishes

Johannes

Hi,
Imagine a 3D particulate channel flow with periodic boundaries along the depth. So the "2D" parabolic velocity profile can be imposed at inlet of channel. The particles are continously inserted at a small region near the inlet.
How can I impose the parabolic profile on the particles? Because with the fix insert commands i can only impose a uniform velocity to all particles. Can I do this by just some additions to the input script, or do I really need to modify the fix insert (say insert/rate/region) code? I would really appreciate any suggestions.

Hi,

I am solving a system which is highly static and only has very low velocity fluctuations. So I end up with very low velocities and with the default precision the simulation ends up at zero kinetic energy and shows NaN as kinetic energy. How is it possible to increase the precision of the solver?

Thanks
Mohammad

Hi friends,
every time when i run script, i got following error;
Reading STL file 'meshes/impe.stl'
Setting up run ...
ERROR: Mesh (id cad2): Mesh elements have been lost / left the domain. Please use 'boundary m m m' or scale/translate/rotate the mesh or change its dynamics (/build/liggghts-QCz4in/liggghts-3.3.1+repack1/src/multi_node_mesh_parallel_I.h:567)

Please help me to resolve this error,

Thanks

How can I extract information on the contact model properties in my simulation (e.g., Young's modulus, coefficient of friction, etc.)? For debugging purposes, I want to be able to check that the right contact properties are being applied to different groups of particles and that the coefficient of friction changes when I put in a new 'fix property/global' partway through the simulation. I already know how to extract forces, overlaps, etc. using compute pair/gran/local but this doesn't give me any information on the actual contact model parameters.

Hello,
I am simulating the filling of a box with a large number of particles (10^5 to 10^6): first I insert the particles in a bigger volume and then I let them pack under the action of gravity.

Which is the best choice of processors to parallelize it? I would like that the Z axis is divided into non-constant grid sizes... e.g., so that more processors compute the particles at the bottom of the box and only 1-2 at the top (when the particles will stay for only a short time before packing).

Do you have any suggestion?
Thanks a lot,

rob1