LIGGGHTS® - User Forum

LIGGGHTS® related topics can be discussed here: discussion about models, installation, feature requests and general discussion

Maximum z-cooridnate(height) of pile in a region

Submitted by Skavya on Wed, 09/07/2022 - 10:54

Hi
I would like to find the Maximum z coordinate of particles pile in a region so i tried using
compute zMax all reduce/region region-Id max z
variable zmax equal c_zMax
print "Height of pile = ${zmax}"
i tried by placing run 0 also and giving compute id in thermo style and update_on_run_end also in compute id and how many times i tried it showing me same error
"compute in variable between runs is not current. try using update_on_run_end"
Can anyone help me with this problem
Regards,
Kavya

Is it possible to save dump files in separate folders based on rotation?

Submitted by gibel on Tue, 08/30/2022 - 07:47

Hi, I am doing simulation in rotating drum.
My rotating drum rotates for 60 sec and per rotation is defined as 4 sec.
i.e I am going to have total 15 rotaions.

Right now I am saving whole simulation in a single folder.

For some specific tasks, I need information from each rotation.

Is it possible to save dump files based on each rotaion?
e.g. : for 15 rotations, I would like to have 15 folders with corresponding files from each rotation.

Any help would be appreciated.

Neighbor Page and One Settings

Submitted by estefan31 on Tue, 08/30/2022 - 01:19

My main question here is: should the simulation results be dependent on the values chosen for the neighbor page and one settings?

My neighbor settings are set as follows with the skin set to the diameter of the biggest particle in my simulation, and my particles are uniform or in some cases have a small range of sizes:

neighbor ${maximum_particle_diameter} bin
neigh_modify delay 0 every 1 check yes page 100000 one 2000

Spring-Dashport model

Submitted by braj on Fri, 08/26/2022 - 14:36

Hello LIGGGHTS experts,

I am working in the field of particle dampers and I am very new to the LIGGGHTS world. Therefore, it would be great if I can get some help from the LIGGGHTS community.

I have attached the figure of the Spring-dashpot system, which I am trying to simulate. My question is how I can model the Spring and Dashport, which are connected to the box in LIGGGHTS?

Thank you for your Help.

torsion torque with primitive wall?

Submitted by efrizz on Thu, 08/11/2022 - 23:30

Hello,

How can I enable torsion torque for a primitive wall? Please see the error below. The ordering works for pair_style, but not for wall/gran. Thanks!

fix wall_z1 all wall/gran model hertz tangential history cohesion sjkr rolling_friction epsd torsionTorque on primitive type 1 zplane 0 # floor
ERROR: Fix wall/gran (id wall_z1): Unknown argument or wrong keyword order: 'primitive' (../fix_wall_gran_base.h:131)

% script, up to error

Sinusoidal torque output

Submitted by kees_bulk on Mon, 07/18/2022 - 12:24

Hi,

In my simulation a disk is rotating around its own axis while translating and where a small part of the disk is submerged within a bed of material.

For my research I need the torque output on the rotation axis. However, when outputting the torque on my rotating disk in a .csv file, I get a sinusoidal torque for each component X,Y,Z, (see picture 1) which is not what I would have expected beforehand. Especially because it moves through 0 meaning my particles give the disk a 'push' at some points in time. Some directions:

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