SYSTEM IDENTIFICATION FOR MODAL AND FLUTTER ANALYSIS OF AN INFLATABLE WING

Abstract

The main objective of the presented work is to understand the aeroelastic characteristics of an inflatable kite. Experimental modal analyses of two test articles are conducted using system identification and signal processing. To understand the flutter behavior of inflatable wings, flutter test articles made from Nylon and Dyneema fabrics are tested first for their modal properties and then for flutter in a wind tunnel. Various experimental techniques are implemented for understanding the modal responses of these two test articles. Instruments such as a 3D-photogrammetry camera system and accelerometers are used to measure the dynamic and static responses of these test articles. Using MATLAB's System Identification Toolbox and Signal Processing Toolbox, the modal parameters are identified from measured responses, such as out-ofplane displacement and accelerations. The experimental and operational modal parameters are then used to estimate the modal responses. The Zimmerman- Weissenburger flutter margin parameter is used to predict the onset of the flutter modes from the identified modal parameters. The verified system identification technologies are leveraged to understand the aeroelastic dynamic instability of a tethered inflatable wing during a wind tunnel test.