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

Abstract

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