LIGGGHTS® - User Forum

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

Continuous run in LIGGGHTS

Submitted by shahabgol on Wed, 04/23/2014 - 11:13

Dear all,

I have a question related to LIGGGHTS. I want to save the simulation run in a specific time (make an initial condition for the final simulation) and start new runs based on this saved simulation. For example, suppose that I have inserted particles and the insertion step is completed, the results are saved and I want to start new runs from this point. How can I accomplish this?

Best regards,
Shahab Golshan

hertz/history damping coefficients coherency

Submitted by SergeiD on Fri, 04/18/2014 - 16:01

Hello.

I have some question about the mutual consistency of the damping coefficients for Hertz's contact model.
From doc for gran/hertz/history (I use liggghts-1.5.1) I got:

gamma_n / gamma_t = 1/2 * (Y/G)^(1/2)

From my own solution for Hertz and Mindlin equations I got:

c_n / c_t = (5/6)^(1/2) * 1/2 * (Y/G)^(1/2)

Comparing my solution with liggghts I see that,

gamma_n = c_n
gamma_t = (5/6)^(1/2) * c_t

[update] Setup LIGGGHTS 3.0.1 on Ubuntu/Mint

PaulWinkler's picture
Submitted by PaulWinkler on Fri, 04/18/2014 - 13:09

Hi,

since version 3.0.1 was released and there are some changes (http://www.cfdem.com/node/42), I updated the basic setup tutorial for Ubuntu(>12.04)/Mint(>14) and maybe other distributions. There is jpg and png support for dump image and back again - mpi support. It's a basic install, without additional packages and tools. The syntax highlighting for gedit was updated to LIGGGHTS version 3.x.

Move/mesh problem[Solved]

Submitted by Nafets on Thu, 04/17/2014 - 14:30

My problem is that i want to rotate a solid body around his axis but this body is rotated by an angle of 40° an moved in my testing area. (as you can see in the picture).

Now the command to rotate a body is for example:
fix move all move/mesh mesh cad1 rotate origin 0. 0. 0. axis 0. 0. 1. period 0.05

So my problem is that i can't explain myself how to modify this command. I hope someone can help me.
Thanks

Dumping Ellipsoid Data

Submitted by cTop89 on Wed, 04/16/2014 - 22:19

I've built LIGGGHTS with the ASPHERE package and was able to generate an ellipsoid particle, but I'm struggling to find how to use a dump command to output data like the shape diameters and the quaternion to define orientation. I'm using "atom_style hybird granular ellipsoid"

Any help anyone could provide would be appreciated, thank you.

weird result: particle discharging from a hopper

Submitted by ZYan on Tue, 04/15/2014 - 15:43

Hi guys,
I am working on the simulation of discharging of particles from a flat bottom hopper. When the discharging is completed, there are one layer of particle sticking to the cylindrical walls. (please see the attached figure). I also attached the meterial properties that i used. Does some one work on similar topics and know the problem? Thank you.

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