LIGGGHTS® - User Forum

Dear all,
I have a question regarding the density of multi-sphere particles.
The density defined in the input, is the density of each sphere or the density of the pack(including some spheres)?
fix pts1 all particletemplate/multisphere 15485863 atom_type 1 density constant 2500 nspheres 17 ntry 1000000 spheres file data/stone1.multisphere scale 0.001 type 1
For example here the density of the cluster will be 2500?
If we create a cluster with more sphere to make a smoother shape the density of cluster will increase?

Dear all,
Is it possible to install two versions of LIGGGHTS on Linux?
Or it is better to delete the old version?
Thank you for replying.

MSchramm,

What are the specific files in your granular bonding program that need to be included? They don't seem to be in a folder for make -yes and make -no compilation purposes.

Thanks

Hello,

So I am creating a region to measure the average velocity at a particular location. It is a block that uses the move and rotation arguments so I feel that it could be very easy to input a wrong value, especially if my input is a time function. I cannot seem to find a way to create a file with this region data so I can superimpose it in Paraview and visually confirm that it is at the right location.

Dear all,

Dear all,
I am using multi- sphere parcels but I do not know why they stick to a plate which I put in the computational box.
#Multisphere

atom_style sphere
atom_modify map array sort 0 0
boundary f f f
newton off

communicate single vel yes

#PUBLIC version only supports serial execution
processors 1 1 1

units si

region reg block -0.5 0.3 -0.3 0.3 0. 0.5 units box
create_box 1 reg

neighbor 0.004 bin
neigh_modify delay 0

#Material properties required for new pair styles

How to create a discrete element library and use it in liggghts, whose particle geometry is totally irregular?
How do I assign percentage, the material being composed of a mix of particles of different geometries?

Hi,

I was trying to calculate the six-component from the global Stress tensor using fix ave/euler command. The dump looks like this for two cells:

SCALARS pressure float 1
LOOKUP_TABLE default
18.087371
14.514210
-0.000000
-0.000000
-0.000000
-0.000000
17.008131
10.089578
-0.000000
-0.000000
-0.000000
-0.000000

But probably ave/euler gives the trace of the stress tensor, how can I calculate all the global six components?

Thanks,
Sounik

Hi all,

I am seeking for an approach to changing the particle density from 2.6e3 kg/m3 to 2.6e6 kg/m3 after using my restart file. Does anyone know which command should I use for realizing this?

We normally set the particle density in command "fix particletemplate/sphere". As I see from the documentation, no fix_modify command can be applied to "fix particletemplate/sphere". So I want to figure out whether there exists a method that we can change the particle density during modelling?

Thank you very much!

Best,
Rachel

Hello,

I am performing some simple powder flowing simulations, and I am interested in seeing the migration of one or more particles through the flow, i.e. tracking it.

I tried defining a group using the following syntax :

region group_test block -0.02 0.02 0 0.02 0 0.04 units box
group group1 region group_test