Online monitoring of flutter stability during wind tunnel testing of an elastic wing with pylon and engine nacelle within the HMAE1 project

Kurzfassung

Flutter testing in high speed wind tunnels is very challenging and costly. In order to enhance safety levels and to increase the amount of scientific output, real time identification methods are indispensable. This paper addresses a technique for fast and reliable identification of eigenfrequencies and damping ratios using operational modal analysis methods. The procedure has been developed by the Institute of Aeroelasticity of the German Aerospace Center (DLR) in Goettingen, Germany. It uses acceleration signals from turbulence excitation during wind tunnel testing for output-only modal identification. The evolution of eigenfrequencies and damping ratios in the range of interest is tracked over time and wind tunnel parameters. In more detail, the paper focuses on a wind tunnel test campaign conducted by the aircraft manufacturer Embraer, the German Aerospace Center, the Netherlands Aerospace Centre (NLR) and German–Dutch Wind Tunnels (DNW) on a highly elastic fiberglass wing body pylon nacelle configuration.