“Steady-State and Transient Analysis of a Squeeze film Damper Bearing for Rotor Stability,”
This report presents a study of the steady-state and transient response of the squeeze film
damper bearing. Both the steady~state and transient equations for the hydrodynamic bearing
forces are derived. The steady-state equations are used to determine the bearing equivalent
stiffness and damping coefficients. These coefficients are used to find the bearing configuration
which will provide the optimum support characteristics based on a stability analysis of the
rotor-bearing system. The effects of end seals and cavitated fluid film are included. The
transient analysis of rotor-bearing systems is performed by coupling the bearing and journal
equations and integrating forward in time. The effects of unbalance, ca vita ti on, and retainer
springs are included in the analysis. Methods of determining the stability of a rotor-bearing
system under the influence of aerodynamic forces and internal shaft friction are discussed.
Particular emphasis is placed on solving the system characteristic frequency equation, and
stability maps produced by using this method are presented. The study shows that for optimum
stability and low force transmissability the squeeze bearing should operate at an eccentricity
ratio ϵ < 0.4.