Instability Vibration by Internal Damping in Flexible Rotors Supported by Rolling Bearings
Aiming at the situation that rotors are prone to internal damping instability vibration under the combined ef-fects of material hysteresis damping and structural internal damping,a dynamic model for flexible rotors internal damping instability is established.The model incorporates the nonlinearities of contact and clearance in rolling bearings,as well as the influences of internal and external damping at the bearing locations.Through kinematic and load analysis of the roll-ing bearings,a contact restoring force expression considering clearance is derived.The characteristics of internal damping instability vibration of flexible rotors are studied using numerical integration methods,and experimental validation was conducted on a single-disc rotor test rig to examine the effect of bearing clearance on the threshold speed of instability.The research results indicate that the ratio of the external damping coefficient to the internal damping coefficient at the disc location has a more significant impact on the threshold speed of instability than at the bearing location,with the threshold speed increasing markedly as this ratio increases.Conversely,the ratio of the external damping coefficient to the internal damping coefficient at the bearing location has a minimal effect on the threshold speed of instability,with the threshold speed being insensitive to this ratio.Furthermore,the system's threshold speed of instability decreases notice-ably with an increase in bearing clearance,and at the same rotational speed post-instability,the limit cycle radius increas-es with increasing bearing clearance.These findings provide valuable guidance and reference for avoiding internal damp-ing instability vibration in the design,assembly,and testing of flexible rotor systems supported by rolling bearings.
rolling bearinginstability vibrationinternal dampingclearancethreshold speed
万方数据
维普
