LIGGGHTS® - User Forum

Hello every body,

I'm new to this DEM field & I'm self learning . I want to simulate particle breakage ( mechanical comminution )- grinding/rolling process in Vertical Roller Mills...So i want to know whether it is possible to simulate this grinding process by applying dynamic motion to imported geometry so that breakage of particle happens..

Thank you

Hi All,

I want to move a mesh on a trajectory. I have the data of the trajectory as a table of time vs velocity or time vs coordinates at every 0.05 seconds. How can I move the mesh in the simulation using the data that I have.

Thanks,

LIGGGHTS (Version LIGGGHTS-PUBLIC 3.8.0, compiled 2023-03-06-18:23:02 by root, git commit unknown)
Created orthogonal box = (-0.02 0 -0.02) to (0.02 0.04 0.08)
3 by 4 by 8 MPI processor grid

Reading STL file 'barrel12.stl' (mesh processing step 1/3)

LIGGGHTS (Version LIGGGHTS-PUBLIC 3.8.0, compiled 2023-03-06-18:23:02 by root, git commit unknown)
Created orthogonal box = (-0.02 0 -0.02) to (0.02 0.04 0.08)
3 by 4 by 8 MPI processor grid

Reading STL file 'barrel12.stl' (mesh processing step 1/3)

Hi All,

I has a liggghts compression code and want to visulaize force chain in paraview. To visulaize force chain, I used these two command lines ("compute_pair_gran_local.cpp" and "dump_local_gran_vtk.cpp").

But I have a issue that force chain cross the simulation domain along x and y direction (see attached pictures). Boundary condition is periodical along x an y direction. There are two walls along z direction. Top wall move down along z direction to create compression.

Dear fellows

Since I am new to ubuntu and liggghts I have problems troubleshooting the attached code after executing make auto in the terminal.
These are my Makefile.user settings:

Hello,

I am a new LIGGGHTS user and during my simulation, I got a strange thing related to no log and dump recorded data at some steps.

The data is suddenly stopped recorded at numerous steps and then it works.

I have checked at several times and got the same phenomenon but in different simulation steps.

Please see attached figures for the details.

I am wondering that does anyone see a similar problem

I appreciate your helps to solve this problem

Thank you in advance.

LTT

Hi I want to perform numerical experiment of a Shear cell test by applying the periodic boundary conditions (as shown in Figure, on a box of 0.0015*0.0015*0.0015m). The aim is to find the friction properties of the particles. The particles are inserted using a factory for 4 seconds (0-4 sec) and then a force of (0.225N) is applied through a top plate for one second (4-5sec). For the next 20 seconds (5-25sec), the force on the top plate is changed to (0.9N) an the shearing action is planned to be induced due to motion of the top plate with a velocity of (1mm/s) in the negative x-direction.

Hi, all,
I am trying to put atoms that meet a certain boolean condition to a group called "inwardatom". This is the code:

variable eatom2 atom "(v_DH>50e-6)&&(v_inOut<0)"
group inwardatom variable eatom2

The error message says:

ERROR: Illegal group command (group.cpp:341)

Can anyone tell me what causes it?

Thanks a lot!

Hello,
I have a question regarding 'heat/gran' command.
In the example code of heat transfer, f_heattransfer is set as one of output.
What is the unit of f_heattransfer? J? or J/s?
If it is energy [J], should the heat rate be calculated by using time step?
Thanks in advance.