This MSc. thesis has been carried out at GE Avio Aero S.r.l. under a mutual industrial agreement between Politecnico di Torino and the company. The aim of this thesis is the development of a tool able to optimize the performances of toothed wheels typically employed in the gearbox of aircraft propulsion systems. According to aeronautical trends, components and gears must weigh less and less e so they tend to vibrate. Forced vibrations at resonance conditions reduce the fatigue life of the component and for this reason, to achieve better dynamic properties is in contrast with the need to reduce its mass.