The vibration reduction mechanism of the Elastic Ring Squeeze Film Damper (ERSFD) is investigated.Based on the analyses of forces and motions acting on the journal of a rotor-support system with ERSFD and generalized incompressible Reynolds Equation

the model and differential equations of the vibration reduction mechanism of an ERSFD are set up.The features of the vibration reduction for both ERSFD and SFD are considered and compared.It is found out that SFD is only the special example of ERSFD.Theoretical analysis reveals that ERSFD has a very good dynamic characteristics and can be used for both reducing vibration and retuning the frequencies (critical speeds) of the rotor-support system.