LIGGGHTS® - User Forum

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

Deformation in geomtry import

Submitted by rahulsoni on Wed, 03/27/2019 - 13:27

I am trying to import geometry with the help of following command. However, the imported geometry (after dumping by simulation run) looks distorted and different that the original stl file.


fix screen_stl all mesh/surface/stress file Geometry/Screen_VFinal.stl type 2

I tried with precision and heal settings also but to no luck

fix screen_stl all mesh/surface/stress file Geometry/Screen_VFinal.stl precision 0.00000000000001 heal auto_remove_duplicates type 2

USING LIGGGHTS HOW TO MAKE THE SUPERQUADRIC BONDED PARTICLES AS REALISTIC AS POSSIBLE ACCORDN TO ACTUAL MATERIAL SPECIFICATIONS

Submitted by Ashish James Philip on Thu, 03/21/2019 - 11:36

Hi,
As i am new to DEM simulation using liggghts ,

Based on bonded superquadric particle , we have developed a flexible film. Our objective is to make the flexible film as realistic as possible. For example I need to make a flexible film having properties as similar to a PVC film. Here I have 2 questions,

Issue with particles escaping out of the mesh wall

Submitted by erik2019 on Tue, 03/19/2019 - 10:50

Hi all LIGGGHTS users,

I've encountered an issue with particles escaping out of the nozzle mesh wall. My aim for the simulation is to create a steady state powder flow out of the nozzle which i've uploaded the CAD file. I used ovito as the visualization tool and i noticed the no. of particles started decreasing as the powder flow hits the entry of the nozzle. After zooming, i saw a few particles flying out of the nozzle walls. Any idea how to avoid this? I assumed there is something wrong with my 'fix wall/gran' command.

Thanks in advance.

Periodic BC for moved mesh

furkhat's picture
Submitted by furkhat on Thu, 03/14/2019 - 10:03

Dear community!
I'm trying to conduct the first part of triaxial test -confinig. For this I am moving 6 wall using stress/servo command. This wells shold be periodic.
Does anybody know what kind command should I use for periodic moved wall/mesh?

Below example from my script.

Fix x1 all mesh/surface/stress/servo file meshes/x1_conf.stl type 1 com 0. 0.00175 0.001 ctrlPV force axis 1. 0. 0. target_val 5.0 vel_max 0.05 kp 3

How to use the massflow/mesh command without a mesh .stl file

Min Zhang's picture
Submitted by Min Zhang on Wed, 03/13/2019 - 01:53

I have a complicated geometry and I want to count the particle through any cross-sections (which is basically a plane).

I was thinking to define a plane (for example the "region" command can define a "plane") and then use this massflow/mesh command. I thought it should be straightforward.

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