Interior noise in tiltrotor aircrafts is becoming more and more important. Customers are more aware of noise as a key element for comfort and health. This project aims to investigate two topics to further deepen the analysis and the improvement of interior noise in civil tilt rotors.
The first topic is the Advanced Transfer Path Analysis application in a tiltrotor. ATPA is a powerful analysis method to quantify noise and vibration paths in a complex structure, as well as differentiate air-borne from structure-borne paths.
Currently, simulation models based on SEA are widely used to predict aircraft interior noise. The accuracy of the input model parameters has a direct impact on the model results. The knowledge on how to model junctions is a key point to obtain a realistic model. The experimental characterization of the aircraft through ATPA has the objective to deduce the SEA factors.
As a first step, prior to the paths identification, the complex system has to be defined as a set of subsystems. A clustering technique based on the DTF matrix is proposed here, with the aim of dividing the studied system in vibroacoustic subsystems. Once the subsystems are well-defined, ATPA will be experimentally applied. This will provide a deep characterization of the system from a vibroacoustic point of view and will be used as input for SEA factors derivation.
The second topic is the mitigation of tonal noise through innovative active noise control techniques. Low frequency and tonal noise sources are difficult to be improved with classical passive solutions. Nowadays, ANC systems may reduce noise both locally or globally. Innovation is centered in achieving a remarkable reduction of tonal noise, without increasing too much weight and at a reasonable cost. A complete definition of the architecture and the components ready to be installed will be supplied.