Dynamic behaviour prediction of a rotating shaft and an overhung bladed disk assembly

One of the most important challenges of our century is ensuring, as engineers, the design of the most sustainable machines guaranteeing anyway the right amount of performances. A clear example of this theme comes from the aeronautical field where it is possible to observe the will to push for an increase of weight reduction and aerodynamic efficiency, which lead to energy savings and performance increment. An effort in this sense has been made for what concerns the engine design in an open rotor configuration. An example of this trend is found in the increase of adoptions of the propfan engine. In fact, this architecture can be more efficient from the aerodynamic and thermodynamic point of view. On the other hand, the open rotor configuration and the goal of weight reduction lead to a flexibility increase of the of the engine parts. A particular focus is put on the propeller-shaft assembly. In fact, despite the classical approach for the study of the engine dynamics, which provides the analysis of each component separated, neglecting the Gyroscopic effect, the new trend goes towards a "whole engine philosophy design" analysis. This new way of working is exploited, in this thesis, in order to evaluate the impact of the Gyroscopic effect on a propeller-shaft assembly also in relation to the change of the pitch angle of the blade. To pursue the goal, a series of simple FE models, representing bladed discs mounted on a cantilever shaft, have been realized. From this, it has been analyzed the influence of the gyroscopic effect on the first families of frequencies using the Campbell diagram. At the end a schematic model of the ATR-72 propeller mount has been realized in order to compare the previous results with a case closer to the reality.