LIGGGHTS® - Developer Forum

Topics related to developing with LIGGGHTS® can be discussed here: discussion about implementation details, C++, MPI and debugging tools

[SOLVED] Index handling Particle Bond Model (Potyondy) via cohesion

Submitted by Baric on Wed, 03/08/2017 - 13:25

Hello everybody,

I am currently writing a rigid bond contact model (as from "A bonded-particle model for rock" Potyondy and Cundall 2004) using the contact style cohesion. I have everything working, but I came across an odd behavior:

Give a filename to a contact model

Submitted by Baric on Thu, 03/02/2017 - 10:09

He everybody,

I am writing my own rigid bond contact model and therefore, I am using the cohesion model.
It all works nicely and I want to write in a file all the bonds that have been set and the bonds that are broken at the respective timestep.

In general it is quite easy to do so, but I have hard coded the filename into the contact model. I was wondering if there is a way to give a filename in the input script. I know how to provide booleans like the tangential_reduce in "gran cohesion easo/capillary/viscous".

I am grateful for any idea.

LIGGGHTS 3.6.0 compilation error

Submitted by MiRa on Wed, 01/18/2017 - 10:37

Hello everyone,

when trying to compile the newly released 3.6.0 on my 64 bit Ubuntu, I get the following error message:

In file included from ../dump_mesh.cpp:43:0:
../dump:mesh.h:52:29: fatal error: vtkSmartPointer.h: cannot find file or folder
compilation terminated.

I tried to compile using:

make clean-all
make fedora

Furthermore, I unsuccessfully tried to compile using:
make clean-all
make auto

Does anyone know what the problem could be?

Best regards,
MiRa

Not able to access variables in neigh_list.h for C++ interfacing with LIGGGHTS

Submitted by ishaandesai on Mon, 01/16/2017 - 12:16

Hello all,

I am using C++ interfacing with LIGGGHTS by following an example case given on github.com by the name of QUEST - (lmpqst) mentioned below:

https://github.com/CFDEMproject/LAMMPS/tree/master/examples/COUPLE/lammp...

I am not able to access the following variables from the file neigh_list.h:

int *ilist;
int *numneigh;
int **firstneigh;

Missing reference in rolling friction documentation

Submitted by MiRa on Thu, 12/22/2016 - 09:57

Hello everyone,

when looking at the documentation of the EPSD2 rolling friction model [1] it seems there is a missing reference. In the documentation it says "see Iwashita and Oda" but no such reference can be found on this page.

Best regards,
MiRa

[1] http://www.cfdem.com/media/DEM/docu/gran_rolling_friction_epsd2.html

Bond between sphere particles in a multi-sphere particle

Submitted by yidongxia on Wed, 12/21/2016 - 05:44

The current multi-sphere model assumes a rigid body (non-deformable) for each multi-sphere particle. Is it possible to extend this multi-sphere model as to include bond between sphere particles within multi-sphere body, so that the multi-sphere particle can deform upon impact?

How laser scanned particles as particles in liggghts simulation

Submitted by yyu on Tue, 12/13/2016 - 13:21

Hi CFDEMers/Liggghtsers,

Recently, I had scanned some non particles (like corn) by 3D laser scanner, and the output format of particles is .STL or others. But how to use the scanned particles in liggghts? This quesition puzzled me for a long time, even I searched and went through the related topics in the forum.

Is it possible to use the scanned particles rather than the multi spherical particles by clumping spheres?

Any comment or clue about this is appreciated,

Cheers!
Wei-Han

Multisphere template with single sphere

Submitted by estefan31 on Tue, 12/06/2016 - 22:32

Will I mess up anything in the code if I change line 91 in fix_template_multispheres.cpp to read "if(nspheres < 1) error->fix_error(FLERR,this,"illegal number of spheres");" instead of "if(nspheres < 2 error->fix_error(FLERR,this,"illegal number of spheres");"?

I just want to create an assembly of spheres but get data that is only available to multisphere or aspherical particles. That way I can use multisphere computes to get quaternions and calculate particle rotations. When I use basic spheres and no multisphere fix I can't get particle rotation angles.

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