LIGGGHTS® - User Forum

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.

Hi Guys

So this is not a technical query. I wanted to know how many people use LIGGGHTS for mining related work?

I have used LIGGGHTS for my MSc where I studied the efficiency of a new type of vibrating screen, noting that material handling is not my field of work, I am actually a structural engineer.

Hello, I am a new user of LIGGGTHS public.

I am working on a project which involves a variable speed belt. However, I couldn't find an example or detailed explanation on this.

How can I simulate this with LIGGGTHS public?

Could anyone shade a light on this? I think this is a common problem in a real project?

Thanks.

Hello,

I used compute pair/gran/local in order to find the contact area between two superquadrics. The output gives me 260 mm^2 while the diameter of the particles is 11 mm. The contact is edge-face, so basically this small overlap between face and edge, according to the output, produced the contact area more than twice the face-to-face total contact between the particles.

The question is what does "contactArea" exactly represent? What are the possible reasons why the contactArea found is so large?

Thanks everybody for Your replies in advance!