Dear All,
I have a similar question on relaxation after dynamic run for few time steps. I am twisting a beam for some time steps and relaxing the system to settle using Minimization command (I am using LAMMPs).Using the following commands of LAMMPs in a loop:
variable i loop (Loop starts)
run 1000 (dynamic run)
min_style cg
minimize 1.0e-4 1.0e-6 1000 1000 (relaxation run)
next i (loop ends)
The system is under NVT ensemble with non-periodic BCs. If I do minimization for longer time the system returns to the original configuration and the net twist is zero. If I adjust the parameters of minimization command, the system deforms well, but the results do not match with literature (I mean I get higher regime of elastic deformation).
Can anyone give some input on this or suggest an alternative to relax the system after dynamic run.
Thanks a Lot...I really appreciate your help ..!
Hi, I don't understand well what are you doing there. Why do you interrupt the dynamic run to relax the energy?
Hi Hegoi,
Thank you. I am not interrupting the dynamic run. Instead, I am trying to relax the system after the dynamic run completion for few steps (in a quasi static manner) I do the relaxation for the system, so that the thermo dynamic quantities oscillations would settle down, then again I load the system. repeat the process...
I think, you have to reduce the rate of twisting instead of relaxing on each twist.
I assume you are dealing with a nano-wire (no PBC). I am curious as to your interpretation in the two cases: (1) wire returns to its original position after a long minimization and (2) It deforms but does not return to its original state by adjusting parameters of minimize command. It looks like you have used parameters of minimize command such that the minimization does not go through fully and you get a twisted intermediate state - which most likely will not match literature. Unless one knows more about the system, this is the best one can do.
Best'
Hi Viorel Chihaia,
I fix the ends of the beam during the minimization run (relaxation run).
Hi Verababu
I want to simulate quasi-static behaviour, so I need to relax the system after every few dynamic run steps. I have used very small torsion load 0.093717068 deg/ps .
Hi M. warrier,
As you said, I noticed that the system is in the middle of the minimization. If I do complete minimization for longer time, then the net twist is zero. I want the system to deform in a quasi-static manner, so I intend to relax the system through minimization after every few dynamic runs or deformation runs. Can you please suggest any alternative to relax the system after every few dynamic runs?
It is not clear for me what happen with your system. How the net twist is zero after minimization if you fix the ends of the ends of the beam? Can you send some pictures of the system (especially, before and after minimization)?
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