[lammps-users] additive manufacturing SLM

suniliitd14 · September 27, 2021, 3:11pm

Dear LAMMPS developers and Users
I would like to do MD simulations of additive manufacturing (SLM process) as a similar simulation is described in the paper https://www.sciencedirect.com/science/article/pii/S187770581732828X
I dont know which fix or set command is applicable for laser heating with constant/variable velocity over metal substrate. I will be very grateful for any help to create input scripts for the SLM process.
With best regards
Sunil

akohlmey · September 27, 2021, 4:29pm

You have to read through the paper and carefully study the methodology employed and then see if that can be replicated with the features available in LAMMPS.
I don’t think anybody will do that for you.

suniliitd14 · September 27, 2021, 4:46pm

Following is my script. I have selected a spherical region on the metal substrate and with a move command. But during the simulation it is not moving. Please comment.
I will be grateful to you
Thanks
SUNIL

--------------- INITIALIZATION ----------------------------

units metal
dimension 3
boundary p p p

atom_style atomic

#Fe
lattice bcc 2.856 orient x 1 0 0 orient y 0 1 0 orient z 0 0 1
region box block -50 50 -50 50 -50 0 units box

create_box 1 box
create_atoms 1 box

-------------- FORCE FIELDS -------

pair_style eam/alloy
pair_coeff * * Meyer.setfl Fe

-------- SETTINGS --------------

change_box all x final -52 52 units box
change_box all y final -52 52 units box
change_box all z final -52 52 units box

akohlmey · September 27, 2021, 5:27pm

I don’t have time to debug other people’s inputs.

LAMMPS will do what you tell it to do, if it doesn’t, the most likely explanation is that you didn’t tell LAMMPS the right things to do.
to identify what is causing the issue, you need to start from a simple input that you know is working correctly and where you are sufficiently experienced to understand why. Then you can add new features or make modifications, one step at a time and check if that changed the simulations as expected. if not you have to go back and re-read the documentation and consider the physics and then correct and continue. that way you will eventually get to the final simulation. if you cannot figure this out on your own, you need to find a colleague or collaborator that is willing to work with you on that project. that is how progress in science usually is obtained.

suniliitd14 · October 7, 2021, 11:28am

Dear Developers and USER

I have prepared an input script for laser heating over a metal substrate as given below. A spherical region is defined by using the region with move command. But, during simulations, the selected region does not move and remains fixed. Can anyone suggest to me, how to move selected region with constant speed during simulation?