LIGGGHTS® - User Forum

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

How to compute tangential forces at contact for gran/hertz/history pair style

Submitted by Jing Lu on Fri, 05/22/2015 - 11:03

Hi all,

I'm using 'gran/hertz/history' for pair_style and 'compute pair/gran/local history' to output tangential force, because I thought 'history' in 'compute pair/gran/local' means the 3 components of tangential force in xyz (i.e. ft1,ft2,ft3). However the results are extremely small.

I have tried 'compute pair/local ... p1 p2 p3 p4' but it is said improper for gran/hertz/history (I think it was changed from original lammps).

Some questions about rigid bodies

Submitted by RobertG on Mon, 05/18/2015 - 14:00

Hello,
I'm pretty new with rigid bodies and have some question about it.
First the project. I want to insert rigid bodies with 4 atoms and "free" particles together in an system.
I have written an script, that inserts rigid bodies continuously and it works so far.
But after a time, some rigid bodies fall apart.

Moving mesh 2d

Submitted by kevin.eipe on Mon, 05/18/2015 - 13:43

Hi guys,

I had a query about moving mesh in 2d.
I created granular particles on a lattice and imported a mesh from CAD, and moved that mesh. However, as soon as the mesh got close to the atoms and before they could interact, LIGGGHTS gave an error!

ERROR on proc 0: Internal error (../tri_mesh_I.h:108)
--------------------------------------------------------------------------
MPI_ABORT was invoked on rank 0 in communicator MPI_COMM_WORLD
with errorcode 1.

Long simulation running - help

Submitted by kevin.eipe on Sun, 05/17/2015 - 05:43

Hi guys,

I'm in a bit of a messy situation.

I have a long simulation running (been running for 18hrs +) and did not use restart or write restart command.
I specified a mass of 290 kgs of particles to be input (loose packing) and it is currently only at 88 kgs (after 18 hours, current timestep 1600 out of 2850).
There's warnings of less particles being inserted and its not going to reach 290 mass for sure (hardly inserting any more mass).
I was wondering if I should just abort the simulation. I am in a huge dilemma.

What should I do?

2D simulations no more?

Submitted by kevin.eipe on Fri, 05/15/2015 - 13:54

Hi everyone,

Firstly, Thank you to Christoph Kloss and team for developing the newest LIGGGHTS PUBLIC upate (LIGGGHTS 3.2.0).

I had a simple query; will 2d simulations no longer be supported?

Fix pour and fix pour legacy have been removed, and they were commands for liggghts 2d particle insertion.

Unless my assumption is wrong, and those aren't the only fix commands for inserting particles in 2d?

Cheers everyone.

Thanks,

Kevin

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