Problem with higher strain rate

Dear All
I found that the strain rates for simulating tension or shear at the atomic scale are very high, generally reaching around 10 ^ 10 s-1 (0.01 ps-1), while the highest strain rate at the macroscopic scale is only 10 ^ 3 s-1. Could anyone tell me why the strain rate at the atomic scale needs to be so high?

Thanks!

Have you considered asking your adviser or senior colleagues about this?

This is not really a LAMMPS question and thus off-topic for this category. You could post to the “Science Talk” category instead. But talking to “practitioners” is the best way to get meaningful answers to the “why do we do this?” kind of questions

Thank you for the suggestion !

A typical molecular dynamics simulation samples a simulation time of nanoseconds (microseconds at the most).

Thus it is only possible to reach a steady state when using picosecond-long shear “cycles” (when the Lees-Edwards boundary condition offset “wraps around” back to its initial condition), and thus per-picosecond shear rates.

This is a fundamental molecular dynamics limitation. Theoretically you can extract information at much lower shear rates with advanced nonequilibrium theory. In practice that trades sampling a few long trajectories with many short trajectories, and there is not necessarily a computational advantage.