Piezoelectric driven split pad squeeze film damper for the suppression of sudden unbalanced vibrations in rotor system

Abstract

Blade loss leads to excessive unbalanced vibrations of the rotor system in the gas generator of an aero-turboshaft engine. A squeeze film damper (SFD) cannot meet vibration control requirements owing to its fixed structural parameters. In this study, the outer ring of the SFD oil film is designed as three movable bearing pads. Piezoelectric actuators (PZTs) are used to adjust the oil film force by changing the radial displacement of the bearing pads, and sudden unbalanced vibration control of the rotor system is realised based on a switching control strategy. The oil film force formula of the split-pad squeeze film damper (SSFD) is derived, and a mathematical model of the SSFD-rotor system controlled by PZTs is established using finite element and lumped mass methods. The effects of the bearing pad clearance and stiffness of the PZTs on the rotor vibration characteristics are discussed, and the vibration control effect of the SSFD on the sudden unbalanced response of the rotor system is studied theoretically and experimentally. The results show that rotor vibration can be reduced by reducing the bearing pad clearance and increasing the stiffness of the PZTs. The SSFD can effectively suppress the sudden unbalanced response of the rotor system. The experimental value of the peak transient amplitude of the rotor decrease by 32%, and the rotor orbit in the stable state decreases with increasing PZT voltage.