Floating ring squeeze film damper: theoretical analysis

The non-linear characteristics of squeeze film dampers can frequently promo te multi-stable operation, e.g. jump, or aperiodic response in rotating mac hinery. Such undesirable operation can sometimes be avoided in rigid rotor systems by replacing the rigidly supported damper housing with a flexibly m ounted rigid ring or 'floating' ring, but its applicability to flexible rot or systems is uncertain. This paper investigates theoretically the potentia l of such a modified damper in avoiding aperiodic response in a flexible ro tor rig, built to validate theoretical predictions. Parameters investigated include the stiffness of the damper ring mount, its mass and its damping f or various unbalance loads. For the parameter range investigated, the frequ ency response was highly dependent on the stiffness and the unbalance, some what dependent on the mass, and virtually insensitive to the damping. While aperiodic solutions could be avoided, a careful choice of parameters is ne eded to avoid excessive vibrations. (C) 2000 Elsevier Science Ltd. All righ ts reserved.