Does anyone have a Ligghts code for the Triaxial compression test?

Submitted by wangxiukai on Thu, 05/06/2021 - 14:50

I want to servo the wall with a target confining pressure in LIGGGHTS. But, there are only "target force" that can be choosn in LIGGGHTS. So, we need to obtain the area of the wall and update the area timely. It confuses me a lot.

In addition, can we define functions, use "if" statement and "for" statement like python and other high level programming languages?

I look forward to your answers very much, if you have the relevant code, I would not be very grateful.

Thank you!

Wang Xiukai

Forums:

mschramm | Thu, 05/06/2021 - 19:20

LIGGGHTS has if statements and for loops can be done via labels and jumping
Below is an example of using both in one of my flexible fiber examples (https://github.com/schrummy14/LIGGGHTS_Flexible_Fibers/blob/master/examp...)

# Run until we get the kinetic energy below our set tolerance
run ${set_step} # Run once to set/update all geometries and fixes
label begin_set_loop # Start of the loop
variable old_height equal ${max_h}
run ${set_step} pre no post no # Run so many steps until we check the KE again
variable res equal abs(${old_height}-${max_h})
if "${my_ke}<${ke_tol} && ${res}<${res_tol}" then &
"jump in.read_restart end_set_loop" &
else &
"jump in.read_restart begin_set_loop"
label end_set_loop # End of the loop

wangxiukai | Fri, 05/07/2021 - 14:26

Thank you very much!
Do you work on trixial compression test?

Thank you again.
Wish you have a nice day.

wangxiukai | Fri, 05/07/2021 - 14:42

Dear mschramm,

I want to consult another question.

I am a new user of liggghts. I want to use the liggghts to study trixial compression tests, and then coupled with openfoam.
I learn it by reading the document. But there is too much content.
Do I need to read the document from section 1 to section 11?
How can I get started quickly？
Thank you.

Delinz | Mon, 05/15/2023 - 08:59

Hi Wang Xiukai,

Have you solved your problem "trixial compression tests with liggghts"? Im working on it recently. Could you plz share your case with me?

Thank you!
email:Delinz1@163.com

Delinz

espatinom | Wed, 06/14/2023 - 06:04

Hi,

I am interested to study the shear strength in granular soils with different fines content using DEM. Your example of triaxial test helps. could you please send me a copy to espatinom@unal.edu.co Thank you very much!!!!

Best regards,
Esteban Patino-Marin
National University of Colombia

hajmo30 | Sat, 01/11/2025 - 21:38

I need the triaxial test script to investigate internal erosion. If you have the script for the triaxial compression test, could you please give me a link or share it??

ZY | Wed, 04/23/2025 - 17:28

Hi, guys. I am trying to do the triaxial compression test of mixture of soft and hard material in LIGGGHTS, can anyone share the basic triaxial compression code to me.

foamer94 | Tue, 04/29/2025 - 02:18

Hello everyone,
I am a new user of LIGGGHTS. I have a very basic idea of coding in liggghts but not much. I have to perform TX CD test and for now I am just trying to insert particles in a box of dimensions 38 mm x 38 mm x 80 mm. However, I have been trying this since 3 days and I dont know how many syntaxes I have tried, but I am not able to insert and fully pack the box with particles of different PSD. I have been successful in generating the PSD but the box is always half full and particles seem to be suspended. the maximum I could enter is 5000 particles and not more. Can anyone help me in resolving this? If anyone can share the first portion of TX test where we develop the sample, that would be very helpful. Thanks!