Aerodynamic Flutter Analysis Based on Experimental and Hybrid Modal Parameters

Abstract

The use of experimental data is a relevant topic in aeroelasticity. A new aircraft prototype design and certification involve both flutter analysis and tests. The latter is essential to assess a proper finite element (FE) model for the aeroelastic analysis. The current work perfectly fits in this framework, presenting a novel methodology exploiting data from ground vibration testing (GVT) for flutter calculations. The first application relies on the only experimental modal parameters employed to perform aerodynamic flutter calculation. This method does not necessitate a consistent structural model, allowing fast and reliable computation of the flutter clearance just based on GVT results. This application is especially valuable when it is not possible for a structural dynamic model development, e.g., in the absence of a sufficient amount of technical data. The method also allows combinations of experimental and numerical mode shapes to perform flutter calculations. All or some modal parameters can be incorporated in the standard numerical flutter model, adjusting the computed numerical modes, or adding/deleting a few. The method allows a real true correlation between the GVT results and the numerical model, which is usually very difficult to obtain. This work represents the first case based on a combination of experimental and numerical results, paving the way to various possible levels of hybridization to perform aeroelastic analyses.