LIGGGHTS® - User Forum

I'm trying to compile LIGGGHTS 3.8.0 in CentOS with MPI and without VTK. I used the same process as for Fedora in the documentation, but using yum instead of dnf. Everything seems to be compiling alright, but then when it gets to the end and spits out all the *.o it says

/usr/bin/ld: cannot find : no such file or directory
collect2: error: ld returned 1 exit status

However, when I go to /usr/bin there is an ld there.

Does anyone know what's going on?

Hello everyone

Can anyone suggest a method for inserting particles of range 50-100 micrometer in to a cylindrical container until the container is full.

Thanks in advance
Jyothish

Hello everyone,

If one tries to find official installation instructions for liggghts and goes through the CFDEM website, i.e., LIGGGHTS --> Installation, then this leads to "https://www.cfdem.com/installation". On this website, a link to the official documentation is provided. However, no relevant information can be found in the linked part of the documentation [1].

It would be great, if there was actual, official information about liggghts' installation.

Dear all,
I am doing a research on triaxial test in soils. In my simulation, I have two process, i.e. consolidation and shear process. I want to use the coefficient of friction f=1.0 during consolidation while use f=0.5 during shear process. I haven't found any command about changing this coefficient during simulation. Could anyone please give me a clue about how to realize this function?

Hello all,
I want to replace a large particle with two smaller particles if the contact force exceeds a fixed value (for simulation of particle breakage). Any suggestions how to do it?

I have used the fix break_particle in LIGGGHTS 2.3, but I could not successfully compile that version of LIGGGHTS in CFDEM coupling. So, I decided to find another way to simulate the particle breakage in a CFD-DEM simulation.

Regards,
Shahab

Hello everyone,

I am doing a simulation about triaxial compression test using Liggghts, and I am wondering if there is any command for us to obtain the instant porosity or void ratio so that we can output them into a txt file?

Any suggestion or clue is greatly appreciated!

Best regards,
Rachel

Hello,

I am trying to simulate the behavior of a shear cell and in order to do that I would like to apply a simulation environment reduction by application of periodic boundary conditions. Is it possible to use the Lees Edwards boundary conditions in LIGGGHTS? I read on the internet that this should be achieved through the use of fix nvt/sllod and fix deform but the fix nvt/sllod isn't there anymore, so what could I do in order to do that?

thank you in advance and best regards,

Hi,

i have setup a simulation with 6000 spheres using the "hertz tangential history" contact model and the atom_style granular. Each sphere has a specific radius, initial position and a my_val property (see below). my_val is related to the radius (external lookup table). After running 500000 steps, i change Youngs modulus from 5.00000e+006 to 5.10000e+006 using the fix-line below. In the next dump-file saved afterwards (501000), my_val and radius of 484 spheres (out of 6000) no longer matches.

Why?

Hello everybody,

I want to write out the sums of the forces in x, y, and z of all particles in a defined group at eveyr 100 steps.
So I create a region

region count1 block -0.7 0.7 -3.0 -1.5 0.0 0.6 units box

then I create a goup

group count1 region count 1

Dear all,
In fix heat/gran description has mentioned that:
h_c,i-j = 4 * k_pi * k_pj / (k_pi + k_pj ) * sqrt (A_contact,i-j)
However, based on the references, it seems that h_c,i-j related to the radius of contact circle. Thus, I think the formula should be like the following:
h_c,i-j = 4 * k_pi * k_pj / (k_pi + k_pj ) * sqrt (A_contact,i-j / pi )
Can you kindly tell me that I am right or is there another explanation?
Best regards,
Mohammad