LIGGGHTS® - User Forum

I just started out with LIGGGHTS and after running some of the standard tutorials, I found this Bin Flow turorial, which should work but is not working for me at the moment

Included is my case folder and when running this I get the following error:

Hello, (warning: new to liggghts.....)
I would like to add bonds to the particles from the hopper drain example.
Specifically I would like to bond multiple atoms together to create a ridged
group with the ability to break if a certain force is exerted on the bond.

I have attached a txt file that contains the tutorial script with added changes and both the input file
and script for the attempt at using atom style hybrid bond granular

Any help is greatly appreciated.

Hi!

I am looking for a possibility to account for heat generation due to friction. I have found the following commands that I think they are connected with this issue: heating_normal_hertz/hook and heating_tangential_history. Unfortunately in both cases the link to surface heating "surface sphere/heatable" is a dead one.

Hi everyone,

I want to simulate a remote interaction between particles and a bond's breakage situation when the tensile is over a certain limit. How can I do that?

I feel dumb but when logged in it says go to bottom of page for download - missing!!!!!

JB Perth Australia

Hi everyone,

when using gran model hooke/stiffness, I noticed that the gamman and gammat specified are weird for the case of absolute_damping = 'off'.
In another dem code PFC, the parameter specified for viscous damping is damping ratio, however liggghts gives the expression:
gamma(n)=m(eff)*gamma(n,specified)
I wonder if this gamma(n,specified) has a specific meaning that I ignore.

In PFC ,the expression is:
gamma(n)=2sqrt[m(eff)*kn]*gamma(n,specified)
and the gamma(n,specified) is called damping ratio in the normal direction.

thank you.

I am trying to use store_force_contact in wall/gran and I am using a mesh as the wall. Here is the line I am using:
fix granwalls all wall/gran model hertz tangential history meah n_mesh 2 meashes mesh1 mesh2 store_force_contact yes

But when I add the above keyword store_force_contact yes, then I get the following error:

Error: Invalid fix style: "contactproperty/atom/wall" (../modify.cpp:820)

I also want to output the above force value as well in dump please help me resolve these issues.

Thank you.

Hello,

I have a simulation of a process of sedimentation. Initially the particles are distributed over the whole simulation box but over time they concentrate in one end. To speed up the simulation I have two ideas/questions concerning the effective usage of processor power:

I am trying to run this script file but it is showing that velocity projection on face normal is less than 1e-3.

Script File

#Simple chute wear test

atom_style granular
atom_modify map array
boundary f f f
newton off

communicate single vel yes

units si

region reg block 0. 0.3 -0.05 0.05 0.0 0.2 units box # 30cm x 10cm x 20cm
create_box 1 reg

neighbor 0.003 bin
neigh_modify delay 0

#Material properties required for new pair styles