bending of a nanowire

Hi Lammps users,

I'm running MD simulations to predict the mechanical stability of
metalic nanowires under flexural bending i.e the cantilever beam
problem. The nanowire is subject to the effect of a end load "F" via
the fix "addforce" command e.g fix kick flow addforce 1.0 0.0 0.0..
After running the simulation a certain number of timesteps I measure
the deflection (delta) . I would expect the nanowire to remain static
after a certain amount of deflection, but if i run the simulation more
time steps, the nanowire continues to deflect without stopping. I
need to calculate the flexural moment ( force/deflection) . I dont
think the calculation to be something trivial like measuring the
deflection (Delta) for a given force (F) and plot F vs Delta and
taking the slope to calculate the flexural moment.
It would be greatly appreciated any suggestion or ideas ?.

Thank you
Oscar G.