LIGGGHTS® - User Forum

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

fix rigid and its limitation

Submitted by NielsD on Wed, 02/06/2013 - 10:22

Hello

I have a problem regarding the movement of particles clumped together with the help of "fix rigid".

My simulation consists of a vibrating plane (stl-mesh). The clumps are on the top of this plane.
If I simulate the clumps, the moving behaviour is not like it should be.
My clumps look like cubes and consist for example of 3x3x3 particles of the same size without any overlaps.
The simulation works well for single spherical particles or for clumps with 10x10x1 (like a disk flat on the top of the plane).

using local data as a variable

Submitted by mojgan on Sun, 02/03/2013 - 22:07

Hi,
I am a new user of Liggghts and have some problem. I am trying to use compute pair/gran/local command for calculating the contact force of grains. I know that this compute calculates a local array which can not be used as a variable.
1. how can I perform some math operators and functions on specific columns of this local array (for example use ^ or * and then calculate the sum of all the vector elements)?

Hybrid simulation (granular & peri)

JF's picture
Submitted by JF on Fri, 02/01/2013 - 13:19

Hi all,

It's been a long time since my last visit on the forum.
I hope someone will be able to give me some clues to solve my problem.
I try to perform hybrid simulation with pair_style peri and granular.

First question, do you know if this hybrid simulation is possible with LIGGGHTS ?

From the attached picture, you can easily understand that I want to use the granular pair_style to control the interactions between the particles and the walls.

multi-modules worked at the same time?

Submitted by yuanjl on Wed, 01/30/2013 - 14:38

Hi,
I am new in this plateform, and have some questions in general concerning the LIGGGHTS.

As highlighted by various features, the LIGGGHTS is able to simulate heat transfer problems in complex particle systems. In parallel, the SPH and Electrostatic mudules are available also within this LIGGGHTS package.

Just wonder if we are free to select more than one moduel, such as, these three modules at the same time to simulate the heat transfer processes in, e.g., nano-scaled porous structures?

Thanks in advance

Yuanjl

Neighbor list overflow/ Atom types must start from 1

Submitted by Tamoghna on Wed, 01/30/2013 - 11:39

Hi!

I was trying a simulation with about 20000 particles of 0.003 m diameter. When I use the command for pour/legacy as:

fix ins1 nve_group pour/legacy 20000 2 10001 vol 0.4 100 diam 0.003 0.003 dens 2284 2284 region fac1
fix ins2 nve_group pour/legacy 20000 2 10001 vol 0.4 100 diam 0.003 0.003 dens 2284 2284 region fac2

I get error saying
Neighbor list overflow, boost neigh_modify one (neigh_gran.cpp)

When I use the command for pour/legacy as:

chasing an odd result

Submitted by jgoldsmith on Sun, 01/27/2013 - 16:59

Hi folks,

I am trying to chase down what would cause particles when dropped into a cylindrical container to settle in a bowl shape. that is the outer particles are a number of cm higher than the ones at the center.

I have included an image of the settled particles in this state as well as the input script that was used for this.

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