LIGGGHTS® - User Forum

In the LIGGGHTS documentation, it explains how to use

fix ID all property/global gamman peratomtypepair ... and
fix ID all property/global gammat peratomtypepair ...

to set the normal and tangential viscoelastic damping constants. It also talks about a gamman_abs and gammat_abs alternative to that fix.

However, I cannot seem to set them myself in an input script. The function "deriveContactModelParams" in pair_gran_hooke_history.cpp seems to override any settings I want to make.

A snippet of my contact parameters section looks like this:

Hi everybody,
Is there a easy way to dump the six components of virial stress.
As far as i know, following commands to be used for determining contact forces are not working properly.
1. pair/gran/local
node/601
2. stress/atom
node/361
regards,
Samantaray

Hi,

I am trying to simulate shear flow of soft particles with a given pair interaction. I have a periodic box. Is there a way to implement Lee's Edwards boundary in the gradient direction ?

Lee's Edwards Boundary condition : influence of shear on the periodic images is taken into account by shifting the periodic images according to the bulk shear rate.

Thanks,
Lavanya

hi everybody,
I obtained Neighbor list builds = 3405 on screen
for the following parameters.
neighbor 0.001 bin
neigh_modify delay 0
timestep 1.0e-4
run 1
run 40000 upto

My question is for 40,000 timesteps, I would expect to get 40,000 neighbor list builds from neigh_modify command for delay 0.
Thank you in advance for the reply.
regards,
Samantaray

hello everyone,
I feel confused with some questions on liggghts,

#1. what is the largest number of particles can be simulated in liggghts? depend on the operating system?

#2. when particles contact with wall for a long time,. for example, when many particles were dumped into a container which was imported with STL file, the wear quantity of the all the walls of the geometry became negative infinity(-6E+6) after a long time's run. So if I want to calculate the wear quantity of an immersed surface, I have to import the immersed surface seperately?

Looking forward to your reply

Hi all:

I am completely new to this software. I want to start knowing about LIGGGHTS(DEM). My work is about packing of the sphere under gravitational force based on the work of Cundall (the one who creates Discrete element method).

I am familiar with the knowledge of the DEM (honestly, it is not so hard), but about LIGGGHTS, I dont know anything.

I already installed the software in UBUNTU. I run the example of the packing. One log file has been appeared after running, but honestly I dont know what it is.

I installed paraview viewer, python and ...

Hi!

I am new with linux,

I have a machine with 8 Intel(R) Core(TM) i7-2600K CPU @ 3.40GHz processors.

I am using the following command for multi processor simulation in liggghts.

mpirun -np 8 liggghts < in.rot_chute

The program is running good for sometime after which the systems reboots in itself.

I know that it is not directly related to liggghts, but, it would be great if you could give me some indication about the source of problem. I also tried with 6 processors with same problem.

I apologize in advance for not knowing how to do this -- I would imagine this is pretty simple for someone who knows what they are doing (this excludes me, apparently):

I am trying to develop a sintering interaction (pair_gran_sinter.cpp) for LIGGGHTS 1.4.6, and I need to ensure that it is conserving particle volume as the particles sinter together (see movie below for example). To do this, I need to store an array of initial particle sizes (radii) such that it is available to pair_gran_sinter.cpp for subsequent volume and updated radius calculations.

I installed LIGGGHTS in my local LIGGGHTS directory (myliggghts).
step 1 git clone git://cfdem.git.sourceforge.net/gitroot/cfdem/liggghts myliggghts
My system is Ubuntu.
But in the /src directory, when type "make fedora" ,
make[1]: Entering directory `/home/cheng/LIGGGHTS/myliggghts/src/Obj_fedora'
Makefile:93: angle_charmm.d: No such file or directory.....
.
.when type"which mpirun", message is "/usr/bin/mpirun"

And I can not find the ./lmp_fedora

So what can I do to install successfully?please help me

cheers

cheng

Hi,
I want to visualize force network in grains by paraview. How can I dump force so that paraview can show force chain network?
Thanks for help in advance...
A