LIGGGHTS® - User Forum

I'm a new user and I'm still learning the most helpful commands to run my simulation. In my script I use the ''hertz tangential history rolling_friction cdt'' model. I would like export:
- the collision time
-number of collision
-normal and tangential forces
-energy dissipated

do you know which commands allow me to export these quantities?

kind regards
I hope someone can help me.

Hi All,

Attached are STLs and input script (remove the .txt). I want to know how to run this script so that ins1 runs 20000 time steps then ins2 gets in and runs for 30000 time steps. In short, ins1 will run 50000 time steps and ins2 runs for only the last 30000 time steps.

Thank you for your help.

Hello. I need someone to help me.

I installed and compiled Liggght version 3.3.1 and I have done checking at SRC / version liggghts.h for double check the version.
Then, I have tried many times to run the example. Unfortunately , still it does not work. This is due to my current liggght version is 2.3
8 as stated in terminal.

ERROR :Invalid pair style (/build/buildd/liggghts - 2.3.8/src/force.cpp:181)

What could I do to fix this problem.. Anyone could help me pleased.

Thank You.

Hello!
I am using LIGGGHTS 3.0.7.
I am trying to add a force to the group of particles of a particular type.

Here, what i do:
//create region in which the force should be applied
region field_region block -0.1 0.1 -0.1 +0.1 0 0.1 units box
//define group gg which consists only of particles of type 1
group gg type 1
//trying to apply the force which will try to decrease the speed of the particles
fix mag_field gg addforce 0.0 0.0 +0.3 region field_region

I am trying to extract the total torque on a mesh that rotates about the x axis and I'm having trouble getting the syntax right (LIGGGHTS-3.3). As an example, defining the wall as:
fix mixer all wall/gran model hooke tangential history mesh n_meshes 2 meshes cad1 cad2 store_force yes

can I access the stored forces as shown below?
variable torque atom force_mixer*sqrt(y*y+z*z)

If I try to reduce the x component of the total torque using:
compute c2 all reduce sum v_torque[1]

Greetings,

I have a doubt about the use of a data file. Recently, i was simulating a mill, and instead of use the particletemplate/sphere keyword, i was using a data file to load all the particles. The total amount of particles that i used was 1344278. However, in a second simulation, i increased the number to 1728272, and when compile LIGGGHTS, the program generated a error and then it close unexpectedly.

My question is if there is a limit of particles in a data file, or is a problem with the computer that i use for simulations. My computer has 8 processors.

Hello Everyone,

I have a question about the fix wall/gran command - I am using the ver. 3.3.1. of LIGGGHTS.

I am using boundary p p f and I want three walls, two bounding the simulation and one in the middle (to create two layers)

fix zwallsdown all wall/gran model hertz tangential history primitive type 1 zplane ${bottom_plane}
fix zwallsmid all wall/gran model hertz tangential history primitive type 1 zplane ${mid_plane}
fix zwallsup all wall/gran model hertz tangential history primitive type 1 zplane ${upper_plane}

Hello everybody,
I am a new user of LIGGGHTS and I am running simulations by inserting a particle packing in a fixed volume:

insert/pack ... particles_in_region 100000

Of course, as I expect, I have a "less inserted than required" since less than 100000 particles are needed to fill the volume.

Dear users and developers,

Hi,
(SEE EDIT)

*****UPDATE****
- I have this simulation with a capillary model for cohesion.
- The simulation run without any problem on 32 cores.
- If I add a compute pair/gran/local, a Segmentation Fault happens for 32 cores depending on the mapping of the processors!
- No ERROR for 8, 16 cores or single core.
- If I change the maxSeparationDistanceRatio to 2.0 I have the error for single core!

Do you think there is a bug?
********

*****ORIGINAL POST****