Aeroelastic Modeling, Modal Testing, and Wind Tunnel System Identification of the MARGE II Aeroservoelastic Model

Abstract

Wind tunnel testbeds and their mathematical models are crucial for the development of aeroelastic control laws. Yet, developing accurate aeroelastic mathematical models adequate for control law synthesis remains a challenge. Aeroelastic models often require fine tuning of the unsteady aerodynamic matrices and the finite element (FE) structural model through ground vibration testing to predict the wind tunnel frequency response well. In this thesis, an overview of the aeroelastic mathematical modeling, modal testing, and wind tunnel system identification process of MARGE II—the University of Washington's new aeroservoelastic wind tunnel model—is presented. An alternative to FE modeling for obtaining structural mode shapes is explored: digital image correlation (DIC) modal testing, making it possible to create aeroelastic models without an FE model. Light is then shed on the challenges of wind tunnel frequency response system identification. Finally, the accuracy of two aeroelastic mathematical models (created with FE and DIC-based structural modes) is evaluated by comparing the resulting frequency responses to wind tunnel data.