LIGGGHTS® - User Forum

Hi Everybody,

I am interested in simulating annular shear with multisphere particles. This system contains a moving rough wall that is made from particles.

For spheres, the moving wall can be set up using a "fix move" command (e.g. fix mv1 wall1 move rotate 0.0 0.0 0.0 0 0 1 1) and the simulation runs well. However the particles in the wall group do not move when the multisphere case is run.

Does the "fix move" command apply to multisphere particles, or is there a more suitable alternative?

Thanks,

Daniel

Hi all. I am currently running simulations of a dry chute avalanche using LIGGGHTS-DEM at various different physical sizes. My test case was using particles with a Gaussian distribution from 0.75-1.95 mm with a timestep of 3.54E-7 seconds, material stiffnesses of 60-200 GPa, and an initial input velocity of 10 m/s during a settlement phase. This settlement phase is necessary for ensuring the right packing of particles in a timely manner.

As is has been discussed in the previous topic (https://www.cfdem.com/forums/radiation-model-can-be-added-packed-bed)
My new paper on the paritcle thermal radiation is published in the Journal of Heat Transfer (ASME),the titile is "Modelling effective thermal conductivity (ETC) of thermal radiation for nuclear packed pebble beds",

Dear wall,

I am facing a problem about removing particles in the process of simulation. In my model, the particles are moving inside six stl. mesh walls, if they get in contact with the stl walls, the soil particles should be removed. To help understand, I also draw a picture of my problem.

I don't know which command should I use if I want to remove these soil particles under some certain criterion. Could you help me? Any suggestions would be of great appreciated.

Best regards,
Zheng

Dear all,

I am now using command "move mesh" to move stl walls, the velocity of the wall will change with the time, shown as the variable "v_vyl".

fix leftwall all mesh/surface/stress file meshes/leftwall.stl type 2
fix moveleft all move/mesh mesh leftwall linear/variable v_zero v_vyl v_zero

Hello every LIGGGHTS users and developers,

I am currently using the version of 3.7.0 and expecting the information by the fix contactproperty/atom/wall could generated as an output file.

I tried conventional methods such as:

1. dump local (ERROR: Dump local fix does not compute local info)

2. dump custom(ERROR: Dump custom fix does not compute per-atom info )

Therefore, I really want to know that whether I could have access to the information by this command and how I could be able to acquire it.

Is possible resolve problems that have fluid and particles, for example mills, with a PUBLIC-LIGGGHTS

Hello,

I am modifing the heat transfer model and would like to test it in a fixed particle arrangement. I can simulate this as usual, but therefore the timestep has to be quite small. I wonder if I could deactivate the particle motion, so that just the heat transfer is solved? Then I could choose a way bigger timestep.

I tried to set pair style to none, but this is not possible since the heat transfer fix requires a pair style. And if I remove the integration fix, the temperature is also not calculated.

hello i have question regarding to the shape of the simulation box

as far as i know the simulation box can be defined with

"create_box N reg" command with previously defined geometric domain

is it possible to define a simulation box with mesh/tet region domain or combination of block and cylinder shapes?

thanks.

Dear all,

I am doing a simulation which needs a quasi-static state during my simulation, i.e a triaxial compression test.