The Dynamic Properties of Annular Gas Squeeze Film Dampers

The step jump method is used to characterize the stiffness and damping of flat-faced gas lubricated squeeze film dampers. Analytic solution of a linearized form of the isothermal and compressible Reynolds equation yields closed form expressions for the step and frequency responses of the gas film. Results from the step jump method obtained both analytically and numerically are shown to be good approximations of the gas film stiffness and damping. A Prony series is proven to be an effective constitutive model capable of representing the stiffness and damping of the gas film in both the time and frequency domains in analytic form. Using the analytic constitutive model, closed form solutions for the motion of squeeze film dampers are now possible.