Optimisation of passive/active systems for reduced interior aircraft noise

Aircraft (both fixed wing and helicopters) as well as launch vehicles are subjected to high external dynamic loads, both from mechanical and acoustic origins.Since structural design very rarely includes the reduction of interior noise into account in its specifications, manufacturers often resort to add-on systems to reach acceptable interior noise levels.Passive and active systems are implemented, but the physical complexity of the interior acoustic field leads to a very large number of such systems. On the other hand, the constraint of minimum weight penalty calls for an efficient optimisation of the global treatment.Airbus Group Innovations is developing a numerical tool to ease the designer task. Optivib_kit\texttrademark\space is a Matlab\texttrademark\space based software that allows the spatial as well as the parametric optimisation of a set of active or passive structural control devices. This optimisation can be carried out from a mechanical model of the structure of interest, or from a large set of measurements made on a real test article.In the paper, several examples will illustrate the use and the performance of this piece of software, targeted to the minimisation of vibration levels or that of interior noise.