LIGGGHTS® - User Forum

LIGGGHTS® related topics can be discussed here: discussion about models, installation, feature requests and general discussion

bond limit issue

Submitted by liggghtschr on Fri, 10/13/2017 - 15:38

When trying to create bonds in "LIGGGHTS-WITH-BONDS" , I get the following error:

creating bond btw atoms 726 and 1741 (i has now 12 bonds) at step 1001
creating bond btw atoms 726 and 1743 (i has now 13 bonds) at step 1001
ERROR on proc 0: New bond exceeded bonds per atom in fix bond/create (../fix_bond_create_gran.cpp:485)

About restarting servo wall and outputing its location

Submitted by Zheng Hu on Fri, 10/13/2017 - 06:22

Dear all,

I am using command "read_restart" to restart my simulation and used the same servo wall command as the original code which is applied to create the restart file (shown below).

"fix topwall all mesh/surface/stress/servo file meshes/topwall.stl type 2 com 0. 0. 0.1 ctrlPV force axis 0. 0. -1 target_val 300 vel_max 0.03 kp 1"

Gaussian Radius Distribution

Submitted by limone on Thu, 10/12/2017 - 15:21

Dear All,

I would like to create a gaussian or log-normal particle size distribution, I mean for the particles radii. Unfortunately, I cannot find anything in the documentation, even though someone implemented a "radius gaussian number" in the "in.liggghts_init" (input command file for DEM). For example:

Change servo controlled wall to velocity controlled wall

Submitted by Zheng Hu on Thu, 10/12/2017 - 05:37

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.

Make auto compile error

Submitted by FelipeL on Wed, 10/11/2017 - 19:45

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

Adding New Module

Submitted by crhea93 on Wed, 10/11/2017 - 02:21

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

MPI error

Submitted by liggghtschr on Tue, 10/10/2017 - 15:25

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...

overlapcheck

Submitted by laura on Tue, 10/10/2017 - 11:45

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

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