Active noise control in turbofan aircrafts: theory and experiments Free

This paper presents the activities developed by the authors within the research project M.E.S.E.M.A. funded by the European Commission. A noise and vibration control system using magnetostrictive actuators has been designed and experimentally tested on a large scale (fuselage mock‐up) test article, for controlling noise and vibrations between 150 ‐ 500 Hz. The environmental noise and vibration excitation was representative of a small/medium turbofan aircraft. Firstly a numerical model of the test article has been developed in MSC/NASTRAN coupling the structural part with the interior acoustic volume. Furthermore the experimental characterisation of the test‐article has been carried on. The model, updated by the mean of the experimental results, was employed to derive the required control actuators performances in order to achieve the best control predicted using a well consolidated "feed‐forward" approach. Genetic Algorithms have been employed in order to optimise the positioning of the actuators. Dedicated magnetostrictive actuators have been designed together with light power amplifiers meeting the specifications; on each actuator an optoelecronic sensor, based on Bragg grating, has been integrated to optimize the actuator performance. A two‐level ANVC system has been designed and tested on a full scale fuselage mock‐up. The paper present an overview of the activities developed as well as of the achieved results.