Viscous damping of perforated planar micromechanical structures.
The paper gives an analytical approximation to the viscous damping coefficient due to the motion of a gas between a pair of closely spaced fluctuating plates in which one of the plates contains a regular system of circular holes. These types of structures are important parts of many microelectromechanical devices realized in MEMS technology as microphones, microaccelerometers, resonators, etc.The pressure satisfies a Reynolds' type equation with coefficients accounting for all the important effects: compressibility of the gas, inertia and possibly slip of the gas on the plates. An analytical expression for the optimum number of circular holes which assure a minimum value of the total damping coefficient is given. This value realizes an equilibrium between the squeeze-film damping and the viscous resistance of the holes.The paper also provides analytical design formulas to be used in the case of regular circular perforated plates.
Department of Mechanical Engineering, SUNY, Binghamton, NY 13902-6000, USA.
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Miles