LIGGGHTS® - User Forum

Hey all !

I was wondering if LIGGGHTS is capable of simulating a slurry mixture, or a melt of several ingredients.
I would like to simulate a rather dense mixture of several granular particles, which solidifies over time.

What , in your opinion, would be the best way to describe such a melt , if possible at all ?
what would be the most appropriate values for poisson ratio \ young's modulus, and coefficients of restitution and friction for such a mixture ?
(I know they are defined for proper solids, though i was thinking if there's any way of obtaining that limit of a melt somehow)

Hi all,
I'd like to view particles displacement.
I used compute displace/atom but I think it does not calculate what I want.
As you can see in attached picture I have the distance of particles from Origin.
When I run simulation and I move my particles, I obtain the same pictures!
I want to calculate the displacement of particles from their initial position, not from Origin.
I tried also fix store_coord command but without result (the vector in 0).
Any help?

Thanks in advance

Andrea

Hello,

To vary the particel temperature I'd like to access it by these commands:

variable ramp_temp equal 0.05
fix heattransfer all heat/gran 500

compute temp all property/atom Temp

variable d_Temp atom ${ramp_temp}*c_temp
fix Tramp all adapt 1000 atom Temp d_Temp

... which doesn't work...

The Manual says, that the compute needs per-atom quantities as input, which are stored by LAMMPS and Temp is not a per-atom quantity...

But what I don't understand is, why can I access the per-atom temperature by this command:

Hey liggghts users !

I was wondering if there is any option to model heat transfer
between particles that originates from radiation or convection, rather than
having the particles in physical contact to exchange heat (conduction).

Any ideas as to how to include radiative or convective heat transfer ?

Thanks !
David

Hi LIGGGHTS users,
I want to make walls of my simulation box with granular media but couldn't do that. Can anybody help me doing so?
Thanks a lot,
R

Hey

Hey

Attached below is the code I am using.
Essentially I am pouring particles into a region and then allowing them to settle before rotating them, but I have something a bit weird going on. Between runs 1200-1400 the particles hit the mesh wall of a circular tank on the x-y plane for the first time, and then massively rebound to the extent that the majority of them travel in the positive z direction and leave the simulation domain. The defined region is inside a hollow cylindrical tube mesh which sits directly ontop of the circular tank, and definitely doesn't cross the inserted mesh.

Hi everybody,

I wonder if you guys know an easy way to generate a slab consisting of randomly oriented crystals or not. There will be particles at the atom positions.

Thanks,

Ozgur

Hello everybody,

I'd like to produce a bulk commodity in a container in 2d.
The original LAMMPS insert-commands seem to insert new particles very slowly (I have to wait lots of timesteps, to have all my particles to be inserted), so I tried the LIGGGHTS insert-commands pour/dev and pour/dev/packing.
For both of these insert-commands I need the
- fix particledistribution/discrete command
wich needs the
- fix particletemplate/sphere command
which seems to be available only in 3d.

Is this correct or is there a possibility to use them in 2d?

Thanks in advance,
kind regards

Hey

I've seen a previous post about the error 'too many atom sorting bins', but unfortunately it didn't allow me to solve the problem.

I assume its something to do with my neighbor line, or setting sizes for regions (although I have seen large imported meshes so I don't think it can be the latter. I have tried to find the issue by reading the documentation, but again came across the same error. Attached is my code at the bottom if anyone would be so kind as to have a look?

When I have neighbor 0.05 I have the error 'too many atom sorting bins'. Fine so increase the number...