LIGGGHTS® - User Forum

I can not build this last version of liggghts. even if making in serial manner I keep getting :
/usr/bin/ld: cannot find -latc
what is wrong with this new version?

Hi everyone,

I'm using if and label command to generate loops in a script. I'm using the fix ave/time command to write data to a file each time running through the loop. What I want is to write data into a file every loop. But this command replace the data in the file created in every loop time. Are there any methods to add data to a file rather than replace the data in each loop?

Thanks a lot

J. Wang

Hi Friends:

I almost read the documentation of the LIGGGHTS and I'm somehow getting familiar with the commands. I would be thankful if you can help me in fix deposit command.

I followed the pour_dev example to create my own input script, but the output are unacceptable.

What I'm going to do is to pour 1000 particles in cylindrical container (we have boundary interaction with particles) ; and in every pre-specified step, I want to calculate the void ratio (porosity) of deposited particles.

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.