Hi all,
My lammps version is LAMMPS 7 Aug 2019. To elaborate my questions clearer, I’m writing this email to look for some ideas.
I conducted a simulation to equilibrate my system by using “fix npt drag” at 300k and with specific stress fields: 0 stress components except a given shear stress pxz. After a fairly long time, the system is at equilibrium around 300k. And all the stress components reach the expected values except pxx ~ 0.2 even if I try a smaller Pdamp value, which should be closer to 0, like 0.01.
Then I restart the simulation with the exact same setting. However the further relaxation of the system is observed and pxx gets close to ~0.01. Therefore the simulation trajectory is changed significantly.
My questions are:
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Why during the first simulation, I cannot get ~0.01 pxx, even if I specify:
fix 6 all npt temp 300 300 1000 x 0 0 10000 y 0 0 10000 z 0 0 10000 xy 0 0 10000 xz given_val given_val 5000 yz 0 0 10000 drag 2.5 ? -
Why can the system get a slight relaxation in terms of pxx once I restart it, but still hold other stress components and temperature as expected?
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Is drag 0.0 always more recommended than drag 2.5 to get the most accurate results?
The input files for the initial simulation and the restarted simulation are attached if you need them.
I hope I can get some ideas from you guys. Any suggestion would be valuable and helpful. Thanks.
Sincerely,
Joe
restart.in (2.32 KB)
initial.in (2.26 KB)