Squeeze-film Damping In Perforated Torsion Micro-resonators

Along with the progressive development of MEMS technology, MEMS resonator devices are widely used with its excellent mechanical properties. MEMS resonators will be significantly affected by the ambient air because of their small size in the process of working, which is different from the macro-mechanical, especially when the vibration plate is vibrating close to the substrate vibration, the gas gaps film in the gap will generate higher damping effect on the device, which is also named the squeeze film damping. As one of the air damping,squeeze film damping is a main energy dissipation mechanism in the working process of the MEMS resonator devices, so it has a important influence on the quality factor which is a key indicator for measuring the dynamic characteristics of MEMS resonant. Therefore, how to predict the squeeze film damping accurately has became the key for designing resonant devices with high quality factor.For the squeeze film damping of devices working under the atmospheric pressure, the corresponding damping model is often obtained by establishing and solving the Reynolds equation on the basis of the continuum theory. For this kind of devices, the predecessors has do a lot of research.But these researches are main about the MEMS devices of which the motion is extrusion-vibration, there are almost no research about the squeeze film damping in perforated torsion resonators, but this kind of resonant devices are applied more and more widely along with the promotion of the MEMS devices. So in this paper the control equation of the squeeze-film gas in the perforated torsion micro-plate is established by using the modified Reynolds equation proposed by Pandey, the analytical model of the squeeze film damping in two kind of perforated torsion rectangular resonators is obtained by solving the Reynolds equation, then using the CFD module in ANSYS to calculate the numerical model, the validity and accuracy of the analytical model is verified by comparing the results of the analytical model and the numerical model, and the influences of the perforation ratio, vibration frequency, the thickness of the devices and the gas film on the squeeze film damping and the quality factor of the system are also discussed at the same time. This paper provides a theoretical basis and guidance for the optimization design of the perforated torsion resonant devices.