LIGGGHTS® - User Forum

LIGGGHTS® related topics can be discussed here: discussion about models, installation, feature requests and general discussion

Error in loading mesh

Submitted by z3490628 on Tue, 08/08/2017 - 12:26

Hi all,

I am new to this software. I am hoping to create a 100mm*100mm*100mm cube box with spheres inside the box and then applying confining pressure on all sides.

I have tried to import a mesh created from AutoCad (using other computer and copy back to my own computer) using the fix mesh/surface/stress/servo.
However, some errors are happened and the script is terminated.

Can anyone help with this? I have attached with my script. Many thanks.

Josh

How can I add new pair style?

Submitted by fabregas04 on Mon, 08/07/2017 - 14:20

Hi guys,

I want to add new pair style from the LAMMPS to the LIGGHTS.

So, I just copied .cpp and .h file to the src folder in LIGGHTS.

Then what should I do to recompile the LIGGGHTS?

I need specific description for recompiling. (I'm using LINUX)

Please let me know how to recompile the LIGGGHTS.

Finnie wear by single particle impact?

Submitted by -Hauke- on Fri, 08/04/2017 - 14:38

Hi All,

I am running a simple test case by shooting a single particle on an impact plate using different impact angles, velocities and mass.
At all the dependencies of the velocities and the mass are like expected. I just struggle with the results of varying impact angle, because in my case it doensn´t fit with the theoretical results i would expect by finnie. I attached a picture of the results of the simulation for the wear after impact and the curve i would expect for varying impact angles.

bond coefficients

Submitted by rob1 on Thu, 08/03/2017 - 13:23

Hello,

I am trying to simulate the interaction (hertz) between a stl mesh (type 2) and an ensemble of particles bonded together (type 1).
I am using:

atom_style hybrid bond sphere
...
pair_style gran model hertz tangential history
pair_coeff 1 2
bond_style harmonic
bond_coeff 1 1000.0 200.0

Why do I get errors in the bond_coeff command? E.g. index out of bound or incorrect args for bond style (if I insert * instead of 1).
Thanks a lot and have a nice day,

rob1

Advice for the simulation of roller compaction (powders)?

Submitted by neven.marticnevic on Fri, 07/28/2017 - 14:43

Hi all,

I am doing my master thesis (simulation of roller compaction-pharmaceutical powder).

I have verry big problems with high number of particles (mean diameter is 120 µm).

For 1 g of powder I need 700 000 particles. That is a lot because for filling volume of roller compactor I need "rough estimation" 20 milion particles.

So for that many particles I don't have proper hardware.

In roller compactor I must meausre density in specific regions (picture "Density measure").

Simulation time vs Physical Time

Theo_Score's picture
Submitted by Theo_Score on Mon, 07/24/2017 - 02:29

Hi All,

I have a physical system (fully loaded material bin with stones) which physically discharges the material contents in 95 seconds.

I have the same system in DEM (same physical dimensions for the geometry and particle sizes), with a time step of 1.0E-6 sec. The DEM system completely discharges in 20 seconds (20.0E6 time steps).

I mean to ask if there is a relationship between physical discharge time and simulation time. Is there anything wrong with this simulation? Does the DEM system really need to discharge in 95 seconds as in physical system?

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