LIGGGHTS® - User Forum

Hi all,

In the doc of DEM simulation, the effective shear modulus is:
1 2(2+v1)(1-v1) 2(2+v2)(1-v2)
-- = ------------------ + -------------------
G Y1 Y2

but, the in the global_properties.cpp, line 217:
matrix->data[i][j] = 1./(2.*(2.-vi)*(1.+vi)/Yi+2.*(2.-vj)*(1.+vj)/Yj);

The above two don't match, which one is wrong?

Appreciate any help in advance!

Hi guys,
What happened wrong when there is a erro message like Internal error (tri_mesh_I.h:90)? Thank you in advance for your answers
Cheers,
Zyan

I am using a cylinder region to add external force in a domain. The script for the domain is a s follows

region a cylinder z -0.343 -0.004 0.6 -0.4025 -0.2375 units box
fix push all addforce 0.0 0.0 -0.1 region a

Is there any error in the script. Please help me out.

Thanks in advance.

Hi all,
this might be an easy one for some of you, but I can't figure it out.
Basically I want that all particles are fixed/stationary throughout the entire simulation.
Thank you soo much

I am trying to incorporate two separate force fields for two separate block regions in a single input script as I need to giving force in two separate regions

I am using the following script for one block

#zone 1
region spray block -0.0295 0.0555 0.2 0.24 -0.016 0.014 units box
fix push all addforce 0.0 0.1 0.0 region spray

I tried to add the same set of commands for the other for the other zone but its giving error

#zone 2
region spray block -0.01 0.05 0.3 0.4 -0.06 0.01 units box
fix push all addforce 0.0 0.1 0.0 region spray

Hello,
I'm trying to model a mixer, which mixes two different particles. To improve the handling of the results, I'm trying to save the data of the particles/atoms in to different files.
Without any success ...

Here the basic situation:

Hi,

I have 6 particles rotating with the same angular velocity. The rotation is caused by a torque, set by fix addtorque.
The problem is that i cant get the rotational speed by compute property/atom and also in paraview it is shown that the aprticles have no angular velocity but I can see them spinning in paraview.

fix integr all nve/sphere

dear all
I want to simulate separation of heavy and light particles in Knelson concentrator using DEM by LIGGGHTS 3.0.1
this concentrator works with mixture of particles and water but here I ignore the water. heavy and light mineral particles are separated based on differences in gravity and centrifugal forces while the concentrator rotates very fast.
there are some problems I encounter during my simulations:
1) I can not insert particles with specific features like size, density, percent ... uniformly inside the concentrator (look at the input attached file) ?

I have recently started using lammps and am trying to simulate granular poiseuille flow using the LIGGGHTS. Now I want to use gran/hooke as pair_style but it showed me the following error on compilation "Illegal fix property/global command, not enough arguments (fix_property_global.cpp:50)", though I have used all the fixes for the gran/hooke pairt_style. including the coefficient of restitution, young's modulus, poisson's Ratio ,characteristic velocity and coefficient of friction.

Hi,

I'm going to simulate a cylinder with the bottom lid as a rotating disk. I do not need mesh. Is it possible to declare the region in this way or I have to import CAD ?

Thank you in advance for your assistance