LIGGGHTS® - User Forum

Hi,

I used CMake to built an executable for Windows and it worked fine. I needed to do a few modifications to the source code.

1) I changed the fix_addforce.cpp file so that the radius of the particle and the fluid density were taken into account for the force with upward vertical direction. See line 259 and line 299 in the fix_addforce.cpp file attached.

2) I changed the fix_viscous.cpp to modify the drag force for a Bingham fluid. See line 71-84, line 107-110 and line 166-215 in the fix_viscous.cpp file attached.

Hi,

I am currently attempting to model multisphere particles falling onto a bed and a spreader being used to run over the particles. I am having an issue that the particles seem to disappear as they are about to fall onto the bed. I have reduced my timestep and altered the youngs modulus incase it is a force issue between the particles. I do not seem to receive any errors and I was wondering if anyone had any ideas. Thanks, the script is as follows:

log log-000.txt

As mentioned in LIGGGHTS version history, we can use mesh/vtk to dump mesh temperature. I can not find any option in mesh/vtk to do this.
Please, help me.

Hello LIGGGHTERS,

Recently, I tried to simulate bin flow tutorial existing in the forum. By examination of the results, I noticed that the my output might not be coherent with real physic of the system. I have attached two images to this post which shows there are regular spaces between certain value of particles while they fall through the bin. The images correspond to 1st time step and 2nd time step.

I suspicious about the input script. Do you think this problem can be related to insert_every value?

I did the changes in code to get the count of the particle-particle collision (discussed in another forum). But, I also need to count the total number of particle-wall collisions. How can I get this?

Thank in advance

Naveen

Hi,

I am very less knowledge of LIGGGHTS software. Actually after running a test case I tried to create vtk files using lpp tool which I installed from github. But after giving the command in terminal
lpp dumb.filename
it shows the message invalid or wrong chunk size. I set the chunk size 8 on lpp.py file. BUt still it shows the same.
Can you give me any suggection?

Hi,

Four years ago I used LIGGGHTS for generating a 3D packing geometry. At that time I used a virtual machine and installed Ubuntu to run a LIGGGHTS simulation. I read in the documentation the following:

On a Windows box, you can skip making LIGGGHTS(R)-PUBLIC and simply download an executable, as described above, though the pre-packaged executables include only certain packages.

I need LIGGGHTS again now (to generate a 3D packing geometry). But I can not find where I can download an executable. Does anyone have experience with is?

Regards,
Lisa

Hi
I am doing a simulation of density calibration I want to delete all atom doing outside the domain. I am using the following code, but it is not working.

#--------------define region of interest to delete particles outside
region del_region block -0.5 0.5 0.0 1.6 0.0 1.0 units box side out
delete_atoms region del_region
#-----------------------------------------------------------------------------------

I also want to check mass of particle within a region, how can I do it?

Hi, I as wondering if anyone has been able to achieve a free-standing column of grains with only gravity and friction as forces (no cohesion)?

Hi Users,

I want to apply a constant velocity to a specimen until a target value of variables a17 and a15 are reached, afterwards, I reverse the Velocity direction as my variables don't meet them. But, while the loop is working, LIGGGHTS is reading through the loop only once hence the variable is not updated to change the velocity direction.