LIGGGHTS® - User Forum

Hello Community,

I have a question regarding the implementation of the contact models. Like I understand and has been discussed allready in the forum Liggghts follows the integral implementation of the spring force according Di Renzo and Di Margio. Thats fine. I am more unsure about the implementation of the damping force and the coulomb criterion.

Like i understood from literature there are 2 ways:

1) First check tangential spring forces for coloumb considering the normal spring force and than add the damper afterwards in both cases if necessary:

Hello,

Does LIGGGHTS have the linear spring-dashpot contact model? If not, how can it be implemented?

Hello everyone,

I have installed LIGGGHTS successfully by the file 'makefile.auto' in source. And I can successfully run the examples provided in the examples/LIGGGHTS/Tutorials_public such as the chute_wear by the command 'lmp_auto < in.chute_wear'. But for some reasons I'd like to build LIGGGHTS as a shared library. Having done this, when I tapped 'lmp_auto' in the terminal, it got error as 'bash: lmp_auto: command not found'. However, command 'python chute_wear.py in.chute_wear' ran with no errors, where 'chute_wear.py' is a file shown as follows

I am Stephen and a beginner of LIGGGHTS. I am interested in simulating undrained cyclic triaxial test, but I am not finding the resources, could anyone please share them with me?

This is my e-mail address: akosah@tongji.edu.cn/akosah.as@gmail.com.

Thank you.

Kind regards,

Stephen.

I have created a particle growth simulation in LIGGGHTS using fix command:
fix ID group-ID insert/pack seed seed_value distributiontemplate dist-ID general_keywords general_values pack_keywords pack_values ...

I want to shrink the same particle. The growth that has already happened, I want to undo the process overtime again.

I don't understand how to proceed it.

Dear all,
I am trying to set up a simple simulation with particles settling in stagnant water.
To run the simulations I need both in.liggghts_init and in.liggghts_resume. What is the role of these two scripts respectively.
If I change for instance the timestep or the dump in in.liggghts_init, it does not affect the simulation. It appears that the simulation is reading these settings from in.liggghts_resume. Are they then needed in in.liggghts_init.
Thank you in advance
Best regards
Bjarke

Hello all,

I would like to simulate growth and reduction of particles.
So, I insert particles on system I defined and relax the particles with hertz contact model and cohesion model.
After then, growth and reduction of particles start by using diameter change rates.
As a result, I could get the system volume change during the diameter changing.

Trying to install LIGGGHTS on ubuntu 22.04 with VTK version 7.1. I also checked the opnmpi version which is latest version

But I am facing the following error

Hello Liggghts users,

I have encountered on one problem that I currently can't solve.

I have a filled up cylinder with up-down motion. Riggle move/mesh feature was used for the movement of the cylinder.
Now the task is to track the particles in one exact part of that cylinder, which means that it needs to be moved at the exact same trajectory.

Riggle movement is not implemented in move command of the region. I tried to describe the movement with the movement of the region with rotate feature, but the problem is that I can't see if it is correct.

Hi guys,

I'm using insert/ stream to inject particles from a mesh. I want to make the injection velocity vary along time, like cyclic over time. Can anybody give me a hint on this?

Many thanks,
Jacob