LIGGGHTS® - User Forum

Hello,
currently, I'm working with rigid body and spherical particle.
I tried several methods to restart the simulation properly. With out any success.
Can someone pleas give me a hint?

Best regards
RobertG

How could I generate a bidisperse packing with 2 kind of spheres differing, for example, in diameter and density?

Hi to all,

for gran/hooke there is only one friction coefficient necessary. But in reality are 2 friction states possible: Sliding (or dynamic) friction and static friction. Is there any difference in Liggghts, or is this always the same?

Thx
Orangensaft

Hi everybody,
I had started out with LIGGGHTS a while ago, and know a few basic commands. I would like to know if it is possible to add mass (or) density for that matter, to any of our imported geometries. eg I am importing a box (.stl geometry) and pouring particles inside it , but i also require the box to be of a particular mass. Is there a way to do it ? , or are there any other alternate solutions ? Kindly help.

thanks
anand

Dear all,

I want to dump movie with liggghts in my fedora system. How to change the makefile and make it with ffmpeg support? I've added "-DLAMMPS_FFMPEG" but it failed.
Thanks a lot!

Jian

Resolved....

Done!

I have created 3 .stl geometries using the " mesh/surface" command. Now I want to make to of these to make contact without penetrating one another.
for eg. I am trying to oscillate one geometry , which will hit the other one and this will eventually set the particles in oscillation. Can anybody please suggest how do I go about doing this. I have attached a snapshot of my simulation with 3 different geometries ( 3 different colors). Here, the red one needs to hit the green one.

Hello everyone,
I have done a simulation with a large amount of particles flow down a flume to a horizontal container at the bottom which already has particles in it, I want to know the displacement of the particles at the bottom. By enquiring the Manual, I found the "compute 1 all displace/atom", this command do the job of computing the displace of atom in specified group, but I don't know how to dump out the computed results. Can someone give me help? Any suggestion will be appreciate. Thanks!

Best Regards!
Qiao

Hello,

I'm trying to fill a cylinder with cohesive particles, using Hertz and a certain particle size distribution. However, the particles bounce around and/or then just seem to dissapear. I'm not sure whether they go through the wall or if they bounce out of the domain. Initially, I had no problems, but now I do. Changes I've made include switching from Hooke to Hertz, switching from legacy/pour to insert/stream (to allow a PSD), and adding cohesion, but I'm not sure what causes the problem.

Any help would be appreciated. I've added my code below.

hi all,

dt_h = 2.87*(m_eff^2/(r_eff*Y_eff^2*v_max))^0.2

I understand the concept/calculation of effective mass,radius and young modulus for particle-particle.
Eg: 1/m_eff = 1/m1+1/m2; (m1, m2 are masses of two particles).

How is liggghts code calculating for particle-wall? What can the mass of wall be? Is it going to be infinity?

Please help.
Thank you.