LIGGGHTS® - Developer Forum

Hello,
I am debugging a segmentation fault error and have narrowed it down to when the function post_force_primitive calls the function vectorZeroizeN at line number 1104 in the file fix_wall_gran.cpp

My main question is, "what does this else statement do?".
if(deltan <= 0 || deltan < contactDistanceMultiplier*radius[iPart]){
stuff
}
else{
if(c_history){
vectorZeroizeN(c_history[iPart],dnum_);
}
}

Is there a way to check if c_history[iPart][i] exists?

Thank you!

Hello people. I'm working on a simulation of a tensile test with granular bonds. I'm currently using liggghts 3.5.0 with the bondspackage uploaded by richtie. The thing is that I'm trying to get a tension-deformation diagram for the case, but the force output by the command compute/reduce is just too low. The bonds are working as intended, as they break when they should break (the simulation uses a velocity in one end, while the other end is freezed, so the deformation is directly proportional to the time elapsed), but as i said, the force is orders of magnitude wrong.

Hello all,

I want to export all nine components (averaged) for particle (asymmetric) stress tensor with separate kinetic and static contributions. LIGGGHTS at the moment exports 6 components (symmetric) stress tensor.

has anyone implemented this already? Clues on implementation are welcome.

With a quick look it seems fix_ave_euler and compute_stress_atom is the right place to start. Can anyone please confirm?

Thanks and kind regards,
Vinay

Hi,

Hello,
Could someone guide me on where I should look for where each force compute is done? (Contact, bond, other...)
I am working on the gran/bond model and would like to turn off contact forces between bonded particles (since they are part of a singular geometry).
I tried using the grep command to attempt to find where it may be but had no luck.

Thank you!

Heya,

I am also working on trying to have individual material properties for each discreet element. I am, for example. working on spheres that would each have a different youngs modulus in a packed bed. I think this would be best accomplished through a restart file, where I run a simulation, and then modify the restart file (like I am doing right now to provide an individual radius based on an outside algorithm) and then to read in that restart file.

Hey,
I wanted to know if anyone has the link to the class diagram or UML for LIGGGHTS source code, so that it is easier for me to understand the class structure work flow.
Thank you.

Chai

Hello,

I work for the particle radiation in dense granular system. A useful radiation model has been tested in LIGGGHTS, and it is also can be applied in CFD-DEM.
I am not permitted to open my code. But it is very easy to understand the numerical model from my paper:
1.Wu, H., Gui, N., Yang, X., Tu, J. and Jiang, S., 2016. Effect of scale on the modeling of radiation heat transfer in packed pebble beds. International Journal of Heat and Mass Transfer, 101, pp.562-569.(based on LIGGGHTS)

Hello everyone,

I have a question regarding the documentation of gran tangential history.
http://www.cfdem.com/media/DEM/docu/gran_tangential_history.html