LIGGGHTS® - User Forum

Hi everybody,

I am interested in a simulation of a big sphere containing a many smaller particles. I tried this simulation by adding particles of a defined radius on a regular lattice. The problem is that this reguar structure works a a kind of crystalline system with slip planes when I try to deform it.

However I'd like to try another approach by adding the particles without a lattice with the "pour command". Is there a way to use this command with a sphere as the input region (and not a cube or a cylinder)?

regards,
Martin Koester

Hi all,

For the gran/hooke pair style the documentation says that the equation for the elastic constant is:

k_n = 15/16* ...

In the code the elastic constant is calculated as follows:

kn=(16./15.)*sqrt(reff)* ...

So which one is right, the code or the documentation?

Thanks
Yansan

Hi LIGGGHTS users,
In new fix pour/dev, there is no pouring after i continue my simulation with restart file. Can anybody solve my problem?

Thanks in advance...
Ram

Hi,
Could some body please, let me know what causes the following error message:
*****************************************************************
Setting up run ...
Memory usage per processor = 10.1914 Mbytes
Step Atoms KinEng 1 Volume
1 2000 0.0047170791 0 0.0015
......
.........
37000 2000 0.0094914152 0 0.0015
38000 2000 0.0094929527 2.9568818e-05 0.0015
39000 2000 0.0097540535 0.00030106194 0.0015
40000 2000 0.0101535 0.00085611282 0.0015

Hi all,

Christoph,

Is it possible to define multiple materials in a simulation, and if so, do you have any example scripts that do this? I haven't been able to figure this out yet. For example, I want to be able to assign different friction properties for particle-particle and particle-wall interactions.

Thanks,
Chris

Hello everyone,
I'm having problems finalizing my LIGGGHTS installation. I followed the installation tutorial and completed the make step. When it came time to testing the examples, it appears to run, but at the end it returns an error saying it cannot open dump file. Any ideas? Am I having a permissions problem? I've already tested that I can write to the folder.
Thanks in advance!
Carlos

p.s. Here is some sample output:

./LIGGGHTS < examples/LIGGGHTS/cohesion/in.cohesion
LIGGGHTS 1.1.7 based on lammps-10Mar10
Created orthogonal box = (-0.05 -0.05 0) to (0.05 0.05 0.15)

Hi LIGGGHTS users,
I used fix pour command and inserted particles with low number per insertion. Box is filled with 1/5th of the whole. Total number of particles is 30,000 with diameter 0.005m. However, when I filled the same system with other fix pour commands and increase the pouring number then it fills whole box. What is wrong with it?
Thank you in advance for help...
Ram

Is it possible to contrain the rotational degrees of freedom for granular particles?

Christian

Hi,

I am trying to get a text file containing the time history of quantities related to a single ball (eg force, coordinates,velocity).
What is the best way of doing this?
For resultant force on the ball and ball coordinates I have used the following:

variable z equal z[1]
variable fz equal fz[1]
fix extra all print 1 "$z ${fz}" file Myfile.txt