LIGGGHTS® - User Forum

Hi,
i want to calculate local void ratio inside a sample. And i have tried two methods
For the first method, i have try to use "variable...mass"function to calculate the mass of particles in a given region i have set in advance . Then i can derive the local void ratio.but this method always overestimate or underestimate the void ratio because of the existing of particles intersecting with the region boundary.

Hi
maybe the request is not relevant to liggghts but I am using liggghts and have some difficulties in calculating volumetric strain in a specific volume such as a measurement sphere. I was wondering if anybody has developed a matlab code for strain tensor based on the ligggths results.
I will be so gratefull if you help me in this regard.
thank you in advance
ma

I'm new to Magnetorheological Fluid (MRF) simulations and try to get a comprehensive understanding of MRF behavior. I'm working on MRF simulation to obtain shear stress in terms of shear rate and I'm trying to simulate the shear flow of soft magnetic particles by LIGGGHTS software with a periodic box. I want to study the effect of magnetic field on the particle behavior, if possible.

If it's possible, I would appreciate it if you kindly help me and send me a similar LIGGGHTS script file to get familiar with the simulation?

Best regards

Y. Rabbani

Hi all,
I'm going to fill a subspace with particles and then replicating this through the full volume. I inserted the particles by insert/stream command and let them to settle with "fix nve" command. But after useing replicate command for duplicating them, there is a error, can't replicate because of fix atoms properties.

Please let me know if anyone knows why!
Thanks
Elham

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).

Hi,

Hello Liggghts Users,

I wonder wether or not it is possible to create a simulation region that is a slice of a cylinder. For clarification:

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.

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.

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?