LIGGGHTS® - User Forum

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

I am new user of LIGGGHTS and I have to study the granular flow on inclined plane with walls .

1. For that should i design the mesh which is already at desired angel or it can be simple plane with walls and gravity with component in x y and z direction.
2. How to design the inclined plane and and used mesh/gran command
3. how to see the simulation animation with LIGGGHTS.

Please any one clarify my doubts.

Regards
pnkumar

Hi All,

In some book and articles it's mentioned that coefficient of restitution isn't a constant parameter and it depends on impact velocity. I think it isn't implemented in liggghts and it may affect simulation results, so how we should consider this problem?

Thanks in Advance,
Reza

I find that the compute property/atom command dose not work with multisphere, it cant give the force on each atom(fx fy fz). It always be 0 0 0. I guess there should be a restriction along with the compute property/atom command. And I wonder how to get the resultant force on each multisphere body on each time-step.

Hi all.

I've downloaded the Voro++ package and installed it, but I still get the following error while using compute voronoi/atom:

ERROR: Invalid compute style (../modify.cpp:982)

I've followed the steps mentioned in the documentation while installing it, but I'm not sure what the following steps mean:

Hi all,

I'm trying to use langevin thermostat which is described in below link of liggghts:
http://www.cfdem.com/media/DEM/docu/fix_langevin.html

I use LIGGGHTS (Version LIGGGHTS-PUBLIC 3.3.0, compiled 2015-12-14-18:26:11) version of liggghts, but i got this error:
ERROR: Invalid fix style: "langevin" (../modify.cpp:820)

is this command supported by mentioned version of liggghts !??

Thanks in Advance,

Reza

Hi,

Recently, we were able to work in a cluster. Specifically it's a Stack IQ cluster, and we have some troubles with the mpirun command in order to use all the processors. My doubt is how is it work LIGGGHTS with a STACK IQ cluster?,is there a problem with his architecture?

Thanks and cheers

Nicolas.

I want to rotate a cylinder on its own axis at 3000 rpm as well as the origin (0,0) at 200 rpm. I am using move/mesh for this purpose. I am only able to rotate either on the local origin or on (0,0). I am unable to specify two rotations at the same time. Please let me know how to do this as in the manual it says it is possible to specify two rotations on a mesh. I would grately appreciate any help.

The code I am using is:
fix movecad all move/mesh/gran rotate 0.0 0.0 0.0 0.0 0.0 1.0 0.03 cad1