LIGGGHTS® - User Forum

Hi all, I set the units system to be si in the beginning.
Later I used fix mesh/surface/stress and export the pressure/shear/stress by dump mesh/vtk.
what's the unit of the output??? the pressure, shear, stress components??
N? Pa? kPa??
I am not sure.
thanks for help

Regards,
Xiuhan

Dear Friends,

I have a few questions about valid input geometries for LIGGGHTS.
What kind of geometries can LIGGGHTS handle? What softwares can create these kind of files?
I have Gambit, Maya, Autocad on my pc. Are there any tutorials for building geometries for LIGGGHTS?
Should I mesh the geometry and export it to LIGGGHTS?

Regards,
Shahab

Hi everyone,

I have one question about cofficient rolling friction. In my case, I used three different material, called type 1 type 2 type 3. the particles (type 1) alway roll a long time to stop on the plane (type 3). the different rolling frictions from (0.1-10) were tried, But still have the same issue.
the following is the line:

fix m5 all property/global coefficientRollingFriction peratomtypepair 3 0.75 0.1 10.86 0.1 0.65 0.59 10.86 0.59 0.65
pair_style gran/hertz/history rolling_friction cdt #Hertzian without cohesion
pair_coeff

Hi, I along with Christian Richter have re-added the fix breakparticle/force feature in LIGGGHTS 2.3.8. The modified repo can be clone from https://github.com/rahulksoni/LIGGGHTS-PUBLIC

The repo contains a breakparticle example and a successful animation of it can be found at https://www.youtube.com/watch?v=QM4JYtjU8v0&feature=player_embedded

Please have a look and suggest for improvements.

Hello Everybody,

I have a problem with this Error: "Use of region with undefined lattice " ;-)

I want to create a region defined by a VTK-Mesh. Unfortunately i can't read the VTK with the following command: "region myreg mesh/tet file test.vtk scale 0.001 move 0 0 0 rotate 0 0 0" I generated the mesh in NETGEN from a step-file. The same Error appears if I change the name of the file to test2.vtk so LIGGGHTS can't find the file. Am I doing something wrong or is there a bug in LIGGGHTS? I attatched the vtk file.

Greetings
Hendrik

Hi,
I want to start dusty plasma simulation. Is there a way to perform such type of simulation using liggghts (or with CFDEM)?
Thanks in advance for help..
Ram

I was wondering if anyone can explain more about the "history", "periodicity flag" and "triangle id" in compute wall/gran/local command and also how mesh id and triangle id are different from each other. I also need to know if there are 17 output values(in total) for this command or, if there are more than one value for history. I am using "pair_style gran/hertz/history rolling_friction cdt".
any answer is appreciated.

Cheers,
Mahsa

hi,
i want to calculate the volume change according to the change in the diameter of the particles but
i cant able to use the atom style variables in the calculation.

i cant able to use the variable radi for the formulation of the volume and i am getting an error saying
ERROR: Per-atom compute in equal-style variable formula (variable.cpp:895)

variable vtotal equal 1^3
variable vp1 equal ${radi}^3)*3.1415/4
print ----- ${vp1} -----
variable n1 equal (${vtotal}-${vp1})/${vtotal}
print "## quit"
quit

I try to visualize the speed of a running solver. To do this I want to dump into a CSV file for example the elapsed time since the first run and the current time steps. This CSV file can be visualized and periodically updated (e.g. with gnuplot or LiveGraph) to estimate the required time to finalize the simulation and to see the change of the simulation speed.

Hej guys.

I need to use the "move/mesh mesh cad rotate/variable" command because I can spezifiy angular velocity.

My problem:
A)
variable omega equal 2
fix bewegung all move/mesh mesh cad rotate/variable origin 0 0 0 axis 0 1 0 omega ${omega}

B)
variable omega equal 2
fix bewegung all move/mesh mesh cad rotate/variable origin 0 0 0 axis 0 1 0 omega omega

C)
fix bewegung all move/mesh mesh cad rotate/variable origin 0 0 0 axis 0 1 0 omega 2