Vibration transmission suppression for propeller-shaft system by hub-embedded damping ring under broadband propeller force

Abstract

To suppress the vibration of propeller blades and vibration transmission from the blades to bearings under broadband propeller force, a damping ring placed under the propeller hub is proposed. The configuration of the damping ring is introduced first. Then the analytical dynamic model of the damping ring is established. The dynamic model of the propeller-shaft-multiple bearings system with and without the damping ring is developed based on the modal properties of the propeller-shaft-multiple bearings system, the damping ring and friction interface characteristics between them. Node-to-node contact elements are introduced with both normal and tangential relative displacements. The dynamic model is solved by the Duhamel integration of single-degree-of-freedom system and then by employing the superposition method. It is shown that the damping ring can suppress the responses of the propeller blades and the force transmitted to the foundation at the in-phase blade modes of an integrated forming propeller and the longitudinal mode of the propeller-shaft-bearings system. The suppression mechanism is energy dissipation due to the friction phenomena on the interface. The time histories of the contact variables (tangential relative forces) of given contact points on the hub/ring interface are given to illustrate the local behavior of the contact interface. Parametric analysis is carried out to investigate the influence of the inherent damping of the coupled system, rotation speed, tangential stiffness and friction coefficient on the interface. It is shown that the tangential stiffness and friction coefficient on the interface are two key parameters. The theoretical study will provide some references on designing the damping ring for propellers.