Hydroelastic effects and dynamic response of propellers and thrusters

The project aims at solving the in-service problems of azimuthing thrusters related to failure of bevel gears, shaft bearings and seals, which are believed to be caused by large dynamic loads occurring in extreme waves, during intermittent propeller venti lation, and strongly oblique flow. The nature of these dynamic loads is not sufficiently known. Previous studies have not identified loads that, with conventional analysis methods, are sufficient to cause the type of damages occurring in service. Previous studies have not taken the interaction between hydrodynamic loads and structural response into account. In this project, an advanced multi-body simulation of the entire thruster and drive-train will be combined with state-of-art hydrodynamic load models in a coupled analysis that shall enable hydroelastic effects to be studied. Also, propeller-ice interaction loads will be studied in the same type of coupled analysis. The detailed load pattern in the bevel gear will be studied, in order to identify possi ble improvements to the bevel gear design or manufacturing process (the tooth hardening process). With the real dynamic loads properly known, improved mechanical design of the azimuthing thrusters is possible.