LIGGGHTS® - User Forum

Hello,

I have coded an algorithm to generate multi-spheres to describe the shapes I need.

The problem I have now is that, since the spheres generating the multi-spheres are in the order of microns (10-60 microns) and use units SI, when I try to run the LIGGGHTS script I get the following error:

ERROR: Fix particletemplate/multisphere (id pts1): Volume expectancy too small. Change 'volume_limit' if you are sure you know what you're doing (../fix_template_sphere.cpp:447)

Hi,

Why Fix wall/gran and pair/gran allow only one compute of type wall/gran/local and pair/gran/local ???
I want to have normal contact force, tangential velocity and contact length (history) of a contact, simultaneously.

Hossein

Hallo LIGGGHTS expert,

i am using LIGGGHTS-PUBLIC version 3.5. I was wondering if i can install any packages which provides the tool to use the atom_style bond/gran style. If yes then can anyone tell me the procedure for that.

This will be great help for me.

Thanking You
Braj

Hi, I am installimg the public software for the first time in my computer and at first un error with mpi appeared but I was able to solve to then face an error with something about VTK, or so I think. the error message is the following:

I am having trouble extracting data using "compute multisphere". I added the line "compute multi all multisphere property xcm" to the in.multisphere example file just below the already-existing compute command. I then run in.multisphere through the python interface by typing:

from lammps import lammps
lmp=lammps()
lmp.file('in.multisphere')

The file ran fine on 1 processor and all output seemed normal. Then I attempted to extract the value from the compute by typing: xcm = lmp.extract_compute('multi',1,0).

So in a script I read in the restart file, then I defined a compute wall/gran/local. But there is error said compute wall/gran/local should be defined before the first run, which means it should be defined before the read_restart. Okay, I moved compute wall/gran/local to before the read_restart. But there is error again, said fix wall/gran is not defined yet. Okay, so I move fix wall/gran part to before the compute wall/gran/local, which is also before the read_restart. But there is error again, said the wall cannot be defined before the domain box is defined.

I would like to study the particle dynamics of confined flow at a depth where the stress field is fully developed, i.e. the pressure is constant and independent of the vertical position. In order to limit the total number of particles in the simulation, I was wondering if it is possible in LIGGGHTS to define a region in which a higher gravity value can be assigned?
Also, if you can think of another way to achieve this I would be happy to hear your thought.

Hello everybody,

I have decided to switch from si to nano units because I am working with nanoparticles. From the beginning I had the feeling that the simulations are way slower in nano units than in si units. Now I have made the test and ran equal simulations.
I am sorry that I cannot give a complete example here, because I had to make some modifications in the source code. Here a short case scenario:

Dear all

I would like to use this tool for investigation of the sintering process of polymer particles (SLS). I have setup up my initial powder bed and I am also able to heat up the particles by setting a heatsource that I move along the surface (the laser spot). The next step will be to take into account the heat of fusion. I can not see any obvious way to implement this.

Are there anyone that have worked on anything similar, or who have an idea on how to model this. Should I move into the coupling with CFD, and if yes how?

Best regards
Rasmus

I am facing the following error for the giiven pair_style and use of compute property/local:

pair_style gran model hooke tangential no_history cohesion sjkr rolling_friction epsd2 tangential_damping off viscous off
pair_coeff * *

compute c2 all property/local natom1 natom2 ntype1 ntype2

Part fo log file: