LIGGGHTS® - User Forum

Hi there

Is it possible to calculate the force acting on the mesh/surface?

In my simulation, I use the fix top all mesh/surface/stress/servo file bottom.stl type 1 scale 0.03 move -0.015 -0.015 0.1 com 0. 0. 0. ctrlPV force axis 0. 0. -1. target_val 0.0003467 vel_max 5e3 mode auto ratio 0.01 to cap the particles. how can I manage to know the force on the mesh? because I suppose this command will set the wall compress the particles by 0.0003467N.

Thanks
Weijing

Hi,
i m working on mult-isphere particles mixing in cylinder . problem with my simulation is that some of the particles remain suspended during insertion and stick with impeller rod. if there is anyone who can help me out. i m uploading a picture of my problem. please help me.

thanx

Hello,

I am new to LIGGGHTS, so I tried to modify a tutorial example for a granular flow to create a 2D Couette flow. This is the example I am modifying:

https://www.cfdem.com/media/DEM/docu/Section_input_script.html#an-exampl...

I have got so far with the modifications, but I hit a problem. When I try and convert the dimension to 2D using this line:

dimension 2

The error message appears:

I'm trying to investigate how the different rolling friction models in LIGGGHTS effect my simulations. My initial simulation used the cdt model for the particles and walls, and I wrote restart files to prevent me from having to run multiple simulations from the very beginning.

However, when I change the rolling_friction model on the wall/gran fixes, I get an error:

ERROR: Fix contacthistory/mesh (id tracker_mesh1): saved simulation state used different contact history model - can not restart (../fix_contact_history.cpp:528)

Hi,

I wondered if there exists a way of coupling a solid model created in OpenFOAM, which solves the wave equation to a DEM model created in LIGGGHTS? The physical situation is a pipe filled with powder and the solid pipe is vibrated to fluidize the powder. The particle phase is dry (no effect of interstitial fluid) but the powder is affected by the vibrations of the solid model through the motion of the boundary, which changes throughout the solid part and depends on the frequency of vibration.

Kind regards,

Andrew

Can I compile liggghts on a Windows-7 ?
Can somebody provide the procedure for the same?

Thanks,
GAJ

I see the new release has an additional flag that applies to the rolling friction models, the "torsionTorque" flag. I'm having trouble trying to visualize what the "normal torsion" actually is. Could you provide a more in-depth explanation (pictures are helpful!) or provide an article that explains it?

Hi everyone

what are different shapes available other than sphere and cluster of sphere?
how can we define in liggghts?
if it is possible to create a quadric surface or superquadric surface in public version?,if possible please tell the command...

with regards
DINESH KUMAR

Hello,

I wondered if anyone can give me the instructions to install the latest version of LIGGGHTS on Ubuntu 16.04 LTS?

Kind regards,

Andrew

How do you use the fflag and tflag options in fix particletemplate/multisphere? I'm getting an "unknown keyword" error when I use it as follows:

fix particle_template all particletemplate/multisphere 608519 atom_type 1 density constant 1 nspheres 1000 ntry 100000 spheres file template_file.multisphere scale 1.0 type 1 mass 10 inertia_tensor 100 0. 0. 100 0. 100 use_volume fflag off on on tflag on off off