LIGGGHTS® - User Forum

Hello , LIGGGHTS user, I am trying to run a simulation where particle drop and flows one after another in some time interval.
I was able to make a flow of only one particle. When I tried to insert more than 1 particles with different insertion rates and insertevery, it doesn't drop particle in different time interval. In my case all particles are dropping at the same time.

Similarly, I use restart command too, but didn't work for me.

Here is my 'insert command'. I think I did mistake in these commands.

Dear LIGGGHTS users,

I used the contact model hertz, and set computeDissipatedEnergy as well as computeElasticPotential on. The manual says this setting saves the dissipated energy and elastic potential for use in fix calculate/dissipated_energy and fix calculate/normal_elastic_energy.

But when I output the variable f_calculate/dissipated_energy, it reports ERROR: Invalid fix ID in variable formula.

Could you please tell me how to solve this problem?

Thank you in advance.

Best wishes,
June

Dear LIGGGHTS users,

I want to monitor the change of total energy during dynamic relaxation. But I don't find the command to compute the total energy, and there is no thermodynamic output of the total energy. So how can I output the total energy of the system？

Thank you in advance.

Best wishes
June

Hello
I am a new user of LIGGGHTS-flexible fiber version. My problem is similar to the shear tutorial. Its different in a sense that in my case I intend to make cross-linked fiber bonds. In order to avoid 'bond loss error', I am using a kinetic energy (KE) based logic, i.e if KE of all atoms is less than a certain thresold, we form the cross-links, otherwise NOT.
Following is the logical statement I am using:

Hello
I am using LIGGGHTS-flexible fiber version. I have a minor question regarding "bond/create/gran" to create granular bonds.
In one of the tutorial the syntax of the above command is as follows:
fix bondcr web bond/create/gran 1 1 1 ${bond_skin_web} 1 6 #every itype jtype cutoff btype newperts

I just wanted to understand the meaning of the last entry (newperts=6)

Thanks

Hi Everyone,

Is it possible to read a specific column of data from a text file?. This file is produced from the fix print, to be used in the next simulation steps.

Thanks

Hi
I am currently using liggghts-flexible fiber version. My question is related to the shear_box tutorial for the same.
Similar to the above tutorial, I first deposit fibers in a confined volume, then compress the fibers from above. For the wall geometry, I am using the .stl files. Once the assembly is fully compressed, I create bonds between the fibers. So, we now have a cross-linked fiber network.

liggghts tutorial "heatTransfer_1" set the temperature using the following codes defined to assign 800 degree to the particles at the right half packing.
see the official web: https://www.cfdem.com/heat-transfer

#set particle temperature for half the bed
region halfbed block 0 INF INF INF INF INF units box
set region halfbed property/atom Temp 800.

Dear LIGGGHTS users,

I tried to insert particles into a cubic simulation box with periodic boundary conditions. The particle sizes vary considerably (Dmax/Dmin=80, D: particle diameter). It is OK to construct the initial packing structure with a core, but when the number of particles become very large and need to use multiple cores, some domains are only filled with large particle with no small particles. I have used "communicate multi" and "neighbor multi" command.

Could you please tell me how to solve this problem?
Any help will really be appreciated.

Hello,
(Edit : Moved to liggghts users forum)
My simulations have been hanging when running them on several nodes. They work fine in a single node with several cpus. I was able to get a Minimal Working Example based on the packing example. Just by adding a single line
write_dump all custom out/dump_initial.gz id