High-resolution vibroacoustic characterization of DLR's Falcon 2000LX ISTAR aircraft

Kurzfassung

In the framework of CleanSky2's Airframe project DA9 - Engine tonal noise is a cooperation between Dassault Aviation and DLR. The project aims to enhance the understanding and mitigation of engine related tonal noise in the aircraft cabin. The presented work was done to get an in-depth understanding of the vibroacoustic behavior of DLR's Falcon 2000LX ISTAR aircraft. A two and a half weeks long vibroacoustic ground test was conducted utilizing artificial shaker excitation and operational engine excitation. The responses were measured using a rowing grid of accelerometers at more than 1200 positions, meaning a subset of about 250 sensors were installed at every given time and then moved along the fuselage in a predetermined way to get a high-resolution measurement of aircrafts fuselage. The accelerometer data was than processed to show operational deflections shapes and calculate experimental structural intensity vector fields to analyze the energy transfer through the structure for optimized placement of active or passive counter measures. Specifically the transport of tonal frequencies generated by the engines was analysed.