ANALYTIC MODEL FOR PERFORATED SQUEEZED-FILM DAMPERS

The concept of a perforation cell to derive simple analytic models for perforated squeezed-film dampers is applied. The perforation cell models the cylindrical volume around a single perforation. An extended Reynolds equation is then used to model the damping due both to the gas flow in the air gap and in the perforations. The method is applied in a rectangular damper with 4...64 square holes to derive the damping coefficient analytically. 3D FEM simulations are used to verify the model. The damping predicted by the model is in good agreement with that obtained with 3D FEM simulations. Sinusoidal small-amplitude velocities are assumed, and micromechanical dimensions are considered with rare gas effects in the slip flow regime (Kn $lt; 0.1).