Abstract
The ability of a squeeze film damper (SFD) to attenuate the amplitude of vibration and to decrease the dynamic forces transmitted to the support system, makes it an attractive means of supporting turbomachinery. The main reasons for using a squeeze film damper on a rotor are to improve the dynamic stability and also to reduce the forces transmitted to the foundation. Generally the squeeze film damper ring is centered by a retainer spring. For linearized stability evaluation this is an acceptable assumption. While evaluating the forced response of a rotor having a squeeze film damper, the damper ring is usually assumed to be centralized in the clearance space through the entire running speed range. During the actual running condition the damper does not remain in the centered position and the damper ring tends to find its own eccentric position. This paper discusses the effect of this non-linear behavior of the damper and on the response. A overhung compressor is used as an example to illustrate the influence of the non-linear damper as compared to the centered damper assumption.