The project basically consists of four sub-projects, all of which deal with the acoustic analysis and optimization of aircraft cabin noise. Considering the increasing challenges of fiber composite materials and their use in modern CFRP fuselage of future single aisle Airbus aircraft a system has been developed to reduce actively the cabin noise in a lightweight fuselage design. The results obtained from fuselage designs with increasing complexity show that the system developed within this project significantly reduces the measured sound power even with a broadband stochastic excitation. In another sub-project numerical prediction tools have been developed and evaluated to calculate surface pressure fluctuations under a transonic turbulent boundary layer on an aircraft fuselage. The calculated results have been validated against wind tunnel measurements (Transonic Wind Tunnel Goettingen, DNW-TWG) and flight test data (DLR-ATRA). A of predictive accuracy 5 dB has been achieved. The project focusses on several flight tests conducted on the ATRA test carrier. The aim of these flight tests is a well-founded measurement analysis of the sound field inside the cabin, including the identification of main sound transmission paths and the emission of sound insWe the cabin. Two test campaigns were carried out at cruise flight conditions using the DLR's ATRA test carrier. Each flight test contained several flight attitudes in order to vary the composition of different sound source strengths. A main result of the tests was the preparation of an extensive experimental database for the validation of numerical and semiempirical cabin noise models. This database contains data from two different cabin sections measured at more than 80 different flight attitudes. By means of this data new models for the sound source location and sound transmission can be developed and validated. The investigations have been completed by psychoacoustic evaluation. The acoustic situation in the aircraft cabin has been assessed by test persons. One objective is to improve the frequency response of the loudspeaker announcements with respect to an optimal speech intelligibility at a given cabin background noise. The results of this investigation show that the cabin safety and comfort can be significantly increased by modifying the frequency components of the announcements and that this effect strongly depends on the position in the aircraft cabin.


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    Title :

    Akustische Rechenverfahren für Flugzeugkabinen, Entwicklung und Verifikation: Lufo IV Projekt Simplifizierte Kabine (SIMKAB) . Abschlussbericht


    Contributors:


    Publication date :

    2014


    Size :

    99 Seiten, Bilder, Tabellen, 46 Quellen


    Type of media :

    Theses


    Type of material :

    Print


    Language :

    German