LIGGGHTS® - User Forum

Hey community,

i need to calculate the temperature of particles grouped in a defined region. Unfortunately I only get zero on the calculated compute command.

Could someone check it and tell what I am doing wrong. What do I have to setup to get it to a file or get the result ?

Thank you very much in advance.

David

I could send you script file on request

1. I try to set the region:
#set region temperature

region regionTemp1 block 0.6 1.5 -0.6 0.6 0 1.4 units box
group sectionTemp1 region regionTemp1

Hi,

I want to increase my wall velocity after a certain timestep. It should be increased at my define formula until run ends. How could I do this please help. Thanks

Hello together,

I have a question about implementing STL files via the fix mesh/surface command.
I know that it is possible to move and rotate the Mesh directly in this command. But as definition, the rotation is only possible around an axis which origin ist the 0,0,0.
Is there a posibillity to change this origin in this command?

The move/mesh command allows to define the rotational axis completely free.
Thanks for your answers,

Best regards,
Nils

Hello,

I am analyzing particles trajectory off conveyor belt. I have these two fixes in the script;

fix conv all mesh/surface file meshes/conv_200.stl type 4 move 0.0 0.0 0.0 rotate axis 0 1 0 angle 13.5 surface_vel 0.5 0.0 0.0 #Thats the conveyor belt
fix h_pulley all mesh/surface file meshes/head_pulley.stl type 4 move 0.0 0.0 0.0 rotate axis 0 1 0 angle 13.5 curvature 1e-6 #Thats the head-pulley

Hi Everyone,

I am a beginner in Liggghts and want to use Paraview for which I need to generate .pwd type of files from the superquadric (3.8.0) release 7. Any guidance will be very helpful. My system is CENTOS 7.

Thanks,
Sounik

Hi all,

I am using the fix ave/euler command to calculate the stress tensor. Can I specify a region to calculate the stress tensor instead of the whole domain? I do not understand the function of basevolume_region but guess it is not used to define the region for the calculation.

Thanks
Linhan

Dear all,

i want to simulate superquadric particles but can't find a feasible way to visualize my simulation data with paraview. Is there any simple solution that works right now?

Best regards

Tobi

Hi,

Now I'm suffering from particles being in wrong position.

I created the mesh as the container and then pour the particles in the container.

After that I push the particles with the other mesh.

But the problem here is some of the particles are getting out of the container and fall continuously.

The thing is that particles should not fall from the container as expected.

Can anyone guess what is the problem?

By the way, I'm using the m m m boundary.

Hi,

I use the compute multi-sphere command to calculate body position, and later I would like to exert a force on each multi-sphere body depends on their position in vertical space(z direction). This used to work for me in only sphere system. For the multi-sphere system,I use similar syntax like following

compute zp all multisphere property xcm
variable prs atom -20.*c_zp[3]
fix pressure crystal setforce 0.0 0.0 v_prs

hello!

I am trying to see the interaction between a structure and particles by using an external coupling with LIGGGHTS. I modeled a structure by using mesh model. So with move/mesh function, I would like to update the mesh's position and velocity from my code and receive the forces applied by particles to my code.

Is it available for LIGGGHTS to read the position and velocity from variables out of the program?
This option of "linear/variable args" seems to be suitable, but still, don't know how to feed those variables in the input file.