It is important to eliminate parasitic damping sources in the apparatus for an experimental spectrometer. The parasitic damping can be subtracted from measured total damping that is due to different mechanisms, such as air damping or support loss. On the experimental front, we develop a thin-film beam shaker apparatus consisting of a bimorph piezo actuator and two fiber-optics probes for displacement measurements on the piezo and sample, respectively. The cantilever sample is sinusoidally loaded at its fixed end. From the shape of experimentally measured resonant peaks, the damping of the vibration system can be determined either by the full-width-at-half-maximum method or lorentzian curve fit. In this work, numerical coupled fluid-structure interaction (fsi) is simulated by the finite element method to extract understand the effects of air damping on the cantilever. Both static beam and vibrating beam are considered for the fsi calculation.