LIGGGHTS® - Developer Forum

Hi All,

I have coded up a bonded particle model based on the paper:
Obermayr, M., Dressler, K., Vrettos, C., Eberhard, P., "A bonded-particle model for cemented sand". Computers and Geotechnics. 01/2013; 49:299 – 313. DOI: 10.1016/j.compgeo.2012.09.001

The attached in-file shows how to use it. The bonds are defined in a read_data file.

Hi all,

I am trying to create my own fixes and am facing some issue.

My objective is to create and break bonds and while the bond is existing there should be a bond force between the 2 atoms.
Once the create bond criterion is satisfied it should enter a bondlist and then a calculated force should be applied on the particles and once the criterion for the bond breakage is satisfied the 2 particles should be deleted from the bondlist.

Hi All,

I have an integrator that will track quaternion orientations. See the attached fix_nve_sphere_orientation.cpp/h files. In order to use this, you have to compile liggghts with the molecule and asphere packages.

In order to use the integrator, you must use a hybrid atom_style
atom_style hybrid granular molecular ellipsoid

The attached input script and read_data file show the usage in greater detail.

You actually dont need molecular atom_style, but I have included it as it is necessary on my way to developing a bonded particle model.

Hi

someone can tell me what units work wear? (for example [mm / year]) please

Regards.

Hi all,

Hi all,

I would like to modify "fix_heat_gran_conduction" in such a way that it can accept matrix of conductivity coefficients, to simulate heat transport inside anisotropic particles.
I was able to make LIGGGHTS compile and accept a matrix of conductivity coefficients, but when LIGGGHTS finishes its run the heat exchanged between particles is zero.
here there are the two fix_heat_gran_conduction code pieces i have just modified:

Hi All,

I would like to implement the liquid bridge model (Deliang Shi 2008) to the LIGGGHTS and study the liquid transfer between particles. The general algorithm is that

If two particles are contacted to each other at previous step, and these two particle move apart at current step, then the liquid is transfered.

Could anyone give me some hint on how to check if two particles are contacted to each other at previous step? Or If you happens to work on the liquid bridge model also, we might discuss that.

Thanks!

Kun

Hi all,

I want to add an orientation, and track it's evolution, to the spherical particles using a quaternion (I will use it after to add a force to the spheres in the direction of the orientation). I have added a quaternion array and a flag to the atom.cpp/h .

Hi All,

Anyone could please instruct me how to add a new property of particles, such as moisture around the particles. I think it could be similar as define a property like temperature of particle, which is already in the LIGGGHTS. But I have no idea about the procedure of working on a new property. Any help or hint would be highly appreciated! If possible, a detailed example is best for me to learn it.

Thanks so much!

Kun
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Hi All,

Hello all,

My colleague and I are trying to port fix rigid/small from LAMMPS sep13 to the liggghts 2.3.7 environment. We are getting tripped up in the barycenter calculation in tri_mesh_i.h. If anyone can give us insight into how we need to modify tri_mesh_i.h or fix_rigid_small.cpp/h, it would be greatly appreciated.

Thanks!
Zamir