High-Resolution Vibration Measurement And Analysis Of The Flight-LAB Aircraft Fuselage Demonstrator

Kurzfassung

A challenge to the analysis of aircraft cabin vibrations regarding acoustic comfort is the identification of propagation paths along the structure. Knowing how mid-frequency vibrations travel through the fuselage allows for the development of simpler and more cost-effective counter measures to reduce cabin noise caused by harmonic sources such as the engines and the axillary power unit. The Acoustic Flight-LAB demonstrator is built closely and in full-scale after a real aircraft fuselage section. It is located in a semi-anechoic chamber providing perfect conditions for the acquisition of a high resolution mid-frequency range vibrational dataset suitable to further test and develop analysis methods otherwise only possible in small scale laboratory tests. An enormous effort was expended to measure and analyse the demonstrator's vibrational characteristics in the low- to mid-frequency range at 12000 measurement points. Besides an overview of the test campaign conducted to acquire the data, the results of an operational deflection shape (ODS) synthesis based on principal component analysis (PCA) are presented alongside energy transfer paths calculated using a novel hybrid Numerical-Experimental approach to structural intensity (STI) analysis using aforementioned deflection shapes.