Development of a tool for power gearbox bearings design

The paper is the result of a study conducted at the Third Parties NPI Department of GE Avio S.R.L. aimed at developing a tool based on models and calculation procedures that allow to determine the fundamental parameters for the design of roller bearings for aeronautical use. Bearings are one of the most critical components in aerospace transmissions because of the environment that they have to perform in. In fact, aerospace bearings are expected to operate at high speeds and high temperature, while minimizing their mass. Therefore, the centrifugal forces increase the hoop stresses on inner rings of the bearings and the presence of tensile stresses leads to initiation and propagation of fatigue crack, thus leading to premature failures. Another design concept that is now followed for aerospace bearings is the integrated design approach in which one of the bearing rings or races is made integral with the mechanical system. This functional integration reduces weight, size and simplifies the integration process. For these reasons, it is important to have a tool that helps in the design of complex bearings. Avio Aero uses several tools to take into account different aspects of roller bearing design. However, the process is lengthy and error-prone due to the need to use multiple design tools. In addition, there is no accurate tool for the analysis of tapered roller bearings. The goal of this thesis is therefore to create an integrated tool that allows to analyze both cylindrical and tapered roller bearings, decreasing design time and increasing reliability.