Squeeze Film Damping Effect of the Micro Airflow in a Sealed Chamber

The squeeze film damping effect generating from the sealed air gap between a vibrating circular thin plate and a fixed substrate is analyzed in this paper. Both the Bessel series technique and the Rayleigh-Ritz energy method are utilized to investigate the gas damping effect on the micro airflow in a sealed chamber. The air pressure distribution of the squeeze film air damping is determined by solving the nondimensionalized and linearized isothermal compressible Reynolds´ equation and combined with the sealed pressure boundary condition. The coupled model of piezoelectric-Si film-micro airflow is derived according to the Rayleigh-Ritz energy method. The air damping factor is extracted. By adding and removing the air damping factor, there is no obvious variation of the resonance frequency of piezoelectric-Si film-airflow coupled vibration. The relation between the bending displacement and the cavity depth indicates that the effects of air damping become more intensive with the reducing of cavity depth