Development of solutions to evaluate some of the key factors for the optimal execution of aerospace bearings

SKF AeroBEAST (Aerospace BEArings Simulation Tool) is the SKF calculation tool designed to meet the specificities of aerospace applications and thinked to make the work of SKF engineers in this sector easier. It takes advantage of the great computing potential of SKF BEAST but unlike it, it gives to the user the possibility to create models and execute simulations easily. The application can also work independently from BEAST and executes certain tasks through calculation modules. The present work is the result of an internship at SKF Aerospace France and it aims to detail the solutions implemented in the SKF AeroBEAST software to allow the users to analyze three key aspects of aerospace bearings: the wear taking place in self lubricating spherical plain bearings, the axial preloading and the dynamic behaviour of the cage in ball bearings. The correct prediction of the wear depth of a self lubricating spherical plain bearing during a duty cycle is a central issue, since it determines the bearing suitability for a particular application. The wear calculation module is based on an experimental wear model described in this work. This module provides the AeroBEAST user with a tool to easily and quickly estimate the wear depth, since its operation requires only the insertion of the bearing features and the operating parameters. The axial preloading increases the bearing stiffness and is tipically required in double row angular contact bearings for high speed applications when it is demanded an high degree of running accuracy. The estimation of the operating axial preload force is necessary to ensure that the initial preload set after manufacturing makes it possible to aim at the value demanded by the application. The operating preload calculation module, whose calculation is based on the Hertzian contact model and on technical documentation, provides the user with an instrument to easily perform this task. The cage is a key component of the rolling bearings for aeroengine applications and its performance affects the bearing performance. Furthermore its dynamic behaviour is not a clear phenomen and is mainly investigated using multibody simulations. At SKF this is done using the BEAST simulation tool, that has great computing capabilities but complex interface. The creation of the BEAST models of ball bearings and of the post-processing codes and their subsequent integration in SKF AeroBEAST will allow the user to run dynamic simulations, provide him with some relevant variables to take into account during the cage design or failure analysis and at the same time will enable him to benefit from a user friendly interface.