LIGGGHTS® - User Forum

Dear all,

I am doing a triaxial compression test using LIGGGHTS. First, I applied six servo controlled wall using command: fix mesh/surface/stress/servo to execute a confining pressure on a cube soil specimen. After this process, I want to execute a constant velocity on the walls instead of a target force on the servo walls. This means I may need to change the servo controlled wall to velocity controlled wall.

Hi!

I have compiled liggghts with make clean-all and then make auto in order to get the latest version of liggghts (3.7). The compile process end without problems but then the system doesn't recognize liggghts, in other words, when i type "liggghts" in the terminal, i get the following message:

Software «liggghts» Is not installed. You can install it by typing:
sudo apt-get install liggghts

Dear all,

I am coding a triaxial compression test using LIGGGHTS and want to apply the command: Fix mesh/surface/stress/servo. I set my servo wall as follows:

Hello all,
I am trying to write a script that will read in values from a datafile and then use that data to preform calculations on each capillary bridge between particles in a fluid bed. I am having trouble, however, employing my newly written module. I have the following line in the header file : PairStyle(cap/vis/field,CapViscHist) and have compiled lammps to include my .cpp and .h files, but I receive and unknown pair_style error when I try and run the input file. Any help would be much appreciated!

Carter Rhea

Dear all,

I am trying to grow particles which works fine on one core but my simulation crashes whenever I try to run it on multiple cores.
I have tried out a couple of things and I am pretty much certain that the "fix adapt" command is causing this issue. I attached the script("growth") the stl file ("quadr")and the error message("error").

I am using a 4 core processor and running other simulations on my computer worked just fine...

Hi,

I have problems with the overlapcheck using liggghts 3.3.1. I would like to get particles without any force or velocity, but when I'm creating the particles they overlap and have a big kinetic energy. I use this command:

fix ins5 nve_group insert/pack seed ${seed} distributiontemplate pdd5 maxattempt 200 insert_every once overlapcheck yes all_in yes vel constant 0. 0. 0. region pi particles_in_region ${nliggghts_CB}

I attached my code. Maybe someone has an idea what's wrong.

Regards,
Laura

Dear all,

I want to ask a question about the times of RUN command. In most cases, we set the determined timesteps for RUN command, e.g. run 400000. Would it be possible that we set a condition until which the code will stop (e.g. run until c_force > 1000)? Could someone give me some clues about how to code this? Many thanks.

Regrads,
Zheng

Hi Guys,

Can you please advise me how I can exert the force on mesh elements?

Regards
Matt

Dear all,

I am facing a problem about saving the maximum of contact force.
I first get the pair-force with:

compute fc all pair/gran/local force
variable fmag atom sqrt(c_fc[1]^2+c_fc[2]^2+c_fc[3]^2)
compute maxfmag all reduce max v_fmag
variable maxcm equal c_maxfmag

There seems no mistakes while operating the above code, however, when I tried to output the result using:

fix data_max all print 10000 "The maximum of contact force = ${maxcm}" file data.txt