Tuning of centrifugal pendulum vibration absorbers for translational and rotational vibration reduction

• CPVAs are tuned to orders jN ± 1 to reduce rotor translational vibration.
• CPVAs are tuned to order jN to reduce rotor rotational vibration.
• The structured vibration modes of CPVA system are critical in the derivation.
• Vibration reduction at a desired order may increase vibration at other orders.
• Tuning between jN ± 1 is effective for system with large substructure number or j.

This note provides an analytical proof of the optimal tuning of centrifugal pendulum vibration absorbers (CPVAs) to reduce in-plane translational and rotational vibration for a rotor with N cyclically symmetric substructures attached to it. The reaction forces that the substructures (helicopter or wind turbine blades, for example) exert on the rotor are first analyzed. The linearized equations of motion for the vibration are then solved by a gyroscopic system modal analysis procedure. The solutions show that the rotor translational vibrations are reduced when one group of CPVAs is tuned to order N − 1 and another group is tuned to order N + 1. Derivation of this result is not available in the literature. The current derivation also yields the better known result that tuning CPVAs to order N reduces rotational rotor vibration.