LIGGGHTS® - User Forum

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

Dear LIGGGHTS users,

I want to apply a constant pressure on the top wall and let the bottom wall being frozen.
Could you please tell me the appropriate command to achieve this?

Thank you in advance.

Best wishes,
June