LIGGGHTS® - User Forum

Hi,

I want to have a massrate that vary in function of time. Is it possible with Liggghts 3.8?

Best regards

Michael Page

Hi, I'm trying to do a cfdem simulation, I try to read a restart file with a liggghts script that contains multi sphere data generated by another script. when compiling the second liggghts script I face an error, incompatibility of fix and set command in multi sphere script. after reading the multi sphere restriction I deleted the heat transfer commands (set command included) and now another error with fix gravity shows up. I read the fix and fix multi sphere command description but I don't know why I get this error? I'll be grateful if anyone has an idea. thanks in advance

Hi everyone
In some papers, the authors increasd the particle density a thousand times to increase the time step.
Can we do that in LIGGGHTS? Is there any paper refer to it?
Best regards

I have gone through the move/mesh command, it gives the option for linear, wiggle, riggle, viblin and vibrot type of mesh motions. However, I want to achieve the elliptical type motion of the body. It is for the simulation of industrial screens. So, it is like there is an inclined meshed screen. The screen should move in the elliptical path without rotation or changing the angle (as shown in the attached figure).

How is it possible to achieve in LIGGGHTS? Someone, please help.

Hi everyone
I am doing triaxial test simulation, and I am unable to control the strain rate of the servo wall.
Can anybody help me in this. I want to attain the strain rate of 1.25 mm/min.

I've had some questions about applying coarse-grain models in LIGGGHTS public version. I would like to put a self-defined coarse grain ratio into the formula in the code. When I checked the normal contact and force model in the code, I happened to notice that there are serval keywords related to the coarse-grained model, such as:
class Force : protected Pointers {
friend class Coarsegraining;

I'm trying to install LIGGGHTS using intel compilers. I get an error that a simple MPI program cannot be compiled while using $make auto. After manually entering the include and lib paths in Makefile.user, I still get the same error. I tried compiling with $make mpi and just replacing mpic++ with mpiicpc in Makefile.mpi, which worked. While this workaround works, it would be nice to figure out what's going on with make auto. Does anybody have any ideas as to what's going on?

Hey everyone,

I'm using DEM for the first time and I have some troubles using the lpp/pizza postprocessing package.

when I'm running the lpp.py script in my post directory where the dumo files are located I get following error:

"python lpp.py
File "lpp.py", line 45
raise ValueError "Invalid or no argument given for chunksize"
^
SyntaxError: invalid syntax"

Is it a problem becaus of python2 and 3? Or what is the main issue I'm facing here?

Hi all,

Is it possible to drop a CAD file under the action of gravity? For example, I would like to drop a sphere CAD file into a bed of particles. I would like to see the depth at which the sphere stops moving.

I looked at the "movecad" command, but it seems like it is actively driving the CAD file with set kinematic parameters. But I want my CAD to start from rest, fall into bed of particles, and stop naturally by the action of the particles resisting. Is this possible?

Best,
Brian

We seem to have developed a segmentation fault on our CENTOS 8 system. Everything was working fine, then all of a sudden we started getting seg faults on our scripts. I've tried downloading a fresh copy of LIGGGHTS and recompiling with $make auto, and I've reinstalled openmpi and openmpi-devel, but we're still getting the same faults. I'm unable to even run the examples. Has anyone had a similar problem?

output from running cohesion :