LIGGGHTS® - User Forum

Dear all,

Does anyone know how to find the porosity in a packing simulation?
The only way I found is to calculate the total volume of the atoms knowing the number of atoms and their radius, but I can't know which volume of the entire container they fill because they don't fill the entire volume of the simulation box.

Thank you in advance

Hello there,

I am currently struggeling with liggghts' examples section. Most of the examples I try just do not work, since I get an error of the type 'invalid pair_style' command.

After I have tried several things, I think the problem lies in the facts that my liggghts is based on lammps 10-Mar10. Eventhough I have a lammps version of 17 nov 2012!

So, can anyone confirm that this is indeed my problem? And if so, can anyone tell me how to ' update' liggghts, such that it will be based on the newer version of lammps?

Thanks in advance!

Greetings.

Hi folks,

I'm trying to install LIGGGHTS with CFD coupling for geotechnical simulations. Getting LIGGGHTS 2.3.4 from the git hub on a clean Ubuntu 12.04 LTS (Because of non released AMD Catalyst Driver for kernel 3.5 and newer.) I installed git and copied the repository successfully. Then I installed paraview (but will use binaries of version 3.98 out of a tarball), mpic++ and g++ (for c++). Running make ubuntuVTK in the src dir it stopps after a while:

Hello,

I seem to be having a problem using the fix wall/region command. My simulation entails building a trapdoor mechanism at the bottom of a region filled with grains. Thus far, I have created the mechanism by generating three "thin" regions that lie next to each other and act as the floor, and then applying the fix wall/region command to each of them to create the walls. My plan is to unfix the middle region at some stage, and the trapdoor mechanism would work.

Hi everyone,

Please take a look at the attached file, it is a picture with two images. The one of the left side is a simulation using series process. The one of the right side is a simulation using parallel process (processors 2 2 1). As you can see, the last one has a lack of particles due to the division of processors. Is it normal this situation?

Regards

Hi everyone,
I'm trying to load a restart file but it keeps error-exiting when I fix my mesh surfaces. I have the original input file that created the restart state, I've checked the log that was output for this case, and as far as I can tell I am specifying the exact same fix properties with the restarted input file.

Hi all,
Sometimes the fix particledistribution doesn't work properly, it only inserts the bigger particle. I was changing some values like massrate, extrude_length, velocity, insertion face, and other, in order to insert all type of the particles that I want. I managed to do it using trial and error, but I don't think that is the best way. So I have two questions:

is there any other way solve this? please show me your method

what does the key seed in fix insert/stream? I've read it in the manual but there is not no too mush information about it.

Hi, All:

I am currently running LIGGGHTS simulation test on a large cluster, if there is no limitation on number of nodes and processors per node, I have two companion questions:

1. Does anyone have an idea how many particles that LIGGGHTS/CFDEM is currently able to simulate?
2. When we do multi-processor simulation, how many number of particles is a reasonable number for one processor?

Thanks for any suggestions in advance!

Roy Li

We are using LIGGGHTS to generate particle flow streams in belt conveyor/transfer chute analyses. A few of our people have noticed an odd behavior with particles becoming "stuck" to the drive pulley, and as of yet, we've been unable to find what we've done incorrectly. Below you will find links to two videos, generated by our own post-processor. Forgive me for the partial results as a bug with STL files prevents the system components (belts, chutes, pulleys) from being displayed, but the particle flows are displayed correctly.