LIGGGHTS® - User Forum

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

Collision detection among particles with different sizes

Submitted by limone on Fri, 01/12/2018 - 18:17

Dear All,

I have a poly-dispersed system (particles with 44 sizes) and I would like to create an output for the collisions between the particles, a list of collisions (for all the collisions) like:

id particle-i | id particle-j | time-step when the collision occurs

To me, what is important is to know the id of the colliding particles. In such a way I can link the id to the radius of the colliding particles and "make statistics" on the "collisions per each particle size".

My input file (in.liggghts_init) is like this one:

Minimum particle size in LIGGGHTS

Submitted by bilalelkassem on Tue, 01/09/2018 - 11:27

Hello,
I want to simulate particle flow i.e. Angle of Repose.
I want to used particle size between 50 and 150 µm but unfortunately it is not working. The particles are spreading outside the container.

Particle greater than 400 µm is only working.
I am using SI units in the code. i.e. 0.0004 (400 µm)

Could you please help me to solve the problem?
Thanks in advance.

Best regards,
Bilal

ERROR in running LIGGGHTS

Submitted by shra1kumar on Thu, 01/04/2018 - 21:00

Hi all,

I am trying to run a LIGGGHTS code on a PC. The compiler is able to almost go through all the steps except the last dump and run commands. I am encountering below error. Can anybody explain what's the exact problem ? I tried searching in forum, but haven't found my luck.

Thanks in advance.

.....
# Dump output
run 1
Setting up run at Fri Jan 5 01:29:03 2018

properties of particles within a data file using the read_data command

Submitted by carlos villavel... on Wed, 01/03/2018 - 14:02

Hello

I'm using the following lines to read the coordinates and some properties of different particles.

Atoms # Atom-ID, Atom-type, Diameter, density, x, y, z

1 1 0.025 2500 0. 0. 0.20
2 2 0.005 2500 0. 0. 0.215
3 2 0.01 2500 0.0125 0. 0.225
4 2 0.01 2500 -0.0125 0. 0.225

Although it works well, I don't know how the program knows the order of the properties. ??? Is there a section on the documentation to see the order of the properties?

Thanks

Project on hoppers

Submitted by Fabeeha on Sat, 12/30/2017 - 15:03

Hello everyone,
I'am a beginner in this filed, I need to select a research topic for my one year MS research project on hoppers using DEM on LIGGGHTS. Can anyone help me with some idea to get a start with my research work. Or kindly suggest me some latest research papers which may have some future recommendations regarding DEM studies on hoppers.

Regards: Fabeeha

How to build the real irregular particle

Submitted by Brian on Sat, 12/30/2017 - 02:20

I am working on building irregular particle mixtures and then importing the geometry to a finite element software.

I ran the "multisphere_stone_restitution" example, but the result is two particle clusters rather than two surfaces wrapping the clusters.

How to generate a surface which can wrap the cluster?

I attached my expected results which are generated from PFC.

Slow simulation speed on HPC

shivagoud's picture
Submitted by shivagoud on Thu, 12/28/2017 - 07:50

Hi,

While running simulations on HPC with multiple nodes, simulations are taking around 12hrs for 2crore time steps loop. Tried with 1024 cores , 640 cores etc.,
Each node has 16 cores and 64 gb ram.
Is there any command needs to be added in script file or any module missing in PBS file?

Please have a look at the attached files.

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