Mechanical stiffness ($k$) alters aggressively by $1/L^3$ based on the glass cladding boundary ($125\ \mu\text{m}$).
Increasing the Magnet Mass drops the resonance frequency ($f_1 \propto 1/\sqrt{m}$), which slows down the overall wave period but increases mechanical momentum.
The total dynamic phase shift accounts for the structural geometric stretching minus a $22\%$ reduction penalty forced by the counter-acting internal core photoelastic effect ($P_e = 0.22$).
Fringe Density Rule: Higher magnetic forces push multi-wavelength phase sweeps ($> 2\pi$), packing dense high-frequency fringe patterns directly at the zero-crossing positions where cantilever mechanical velocity hits its maximum.