VIBRATION ANALYSIS OF A FLAT PLATE UNDER AERODYNAMIC LOADING

Aeroelastic instabilities may occur in aircraft surfaces, leading to fatigue or structure failure. Flutter is an aeroelastic instability that results in a self-excited divergent oscillatory behavior of the structure. A classical two-degree-of-freedom flutter is a combination of bending and torsion vibration modes. A flexible mount system has been developed for flutter tests with rigid wings in wind tunnel. This flexible mount has to provide a well-defined two-degrees-of-freedom system on which rigid wings encounter flutter. Experi-mental Modal Analysis (EMA) and Finite Element Model Analysis (FEM) were performed to verify the natural frequencies and modes prior to any wind tunnel flutter test. The equations of motion of the system were developed using Lagrange s equation. The critical flutter speed was determined by three different methods: the p-method for steady flow, the classical flutter analysis and the k-method for unsteady flow, and comparing with experimental results.