LIGGGHTS® - User Forum

Hello, I would like to change the random position of particles before starting a simulation (I want to do different simulations only changing the starting distribution, just to compare average quantities).
Anyway I am changing the seed number in:
- particletemplate/sphere
- particledistribution/discrete
- insert/pack
in all these 3 commands and anything change! Impossible, there is surely a bug. What I see is that seed is not working.

Thank you,
rob1

Hi,

I was wondering if it is possible to apply/modify the gravitational field to particles after they cross a certain spatial coordinate. Based on what i have seen this could be done by creating groups of particles after they enter a certain region, but i can't seem to make it work.

Any thoughts on this?

Thanks,
Nicolas

Good morning,

I would like to create a gaussian distribution of particle sizes, but in particletemplate/sphere only a 'constant' radius is permitted.
What do you suggest?

Thanks a lot and have a nice day,
rob1

Dear Users,

i was trying to densify a loose packing of multisphere clumps using the fix deform command. I was surprised that this command didnot work for a multisphere sample. the simulation boxed was shrunk but the positions of the spheres and clumps was not changed. Does some one have the same issue?

It worked fine for a packing of spheres.

Regards,
zyan

Hi everyone,

I am looking into LIGGGHTS to do some screw conveyor simulations and I have been trying to run the Continuous mixer examples from this site as a starting point.

I understand they where written in the older version of Liggghts, I have been modifying the input script with the updated syntax fro version 3. I have come up against problems regarding the mesh that is supplied in the example.

I get the following error when I try to run the script:

hello every one ....

If I want to refer to the x direction normal stress at time increment 1 as the variable, sx. How can I accomplish this?

My goal is to set up a conditional statement so that if sx>1000, then something else applies.

Hi, all

I want to modelling particle crushing in LIGGGHTS using replacement method. I have no idea how to create a group of atoms given their coordinates after deleting their corresponding mother atoms. The atoms could be created one by one, but it seems time consuming.

Many thanks in advance,

Su

I am using LIGGGHTS for radial segregation problem in rotating drum. I took examples of the scripts available in the LIGGGHTS tutorials and other places but I am not able to execute the segregation problem.
It would be very helpful if somebody expert in the field could provide me an example script for segregation problem in rotating drum. Thank you.

Hi,

I'm new to DEM simulation using LIGGGHTS and I've got to simulate a transfer chute with conveyor belt. Using the "Conveyor" tutorial in the LIGGGHTS examples folder I have been able to set up my own simulation succesfully.

However, as I reviewed the results in ParaView I saw that the velocity of the particles in the conveyor belt was actually different to that of the conveyor belt itself. As soon as I detected this I decided to re-run the "Conveyor" tutorial and check the particle velocity against the conveyor belt and, as it turns out, they were also different.