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Flutter analysis of fixed and rotary wings

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2019
Çiçek, Orhun
Flutter is a critical stability problem that needs to be considered for the design of fixed and rotary wings. Although flutter susceptibility is addressed during the test phases of the most of the aircraft, an analytical model is required for the determination of flutter boundaries and most importantly for supplying feedback to the design procedure in order to have a structure that is free from flutter. In this thesis, several flutter analysis methodologies are investigated for both fixed and rotary wing structures. For the analytical models, a theoretical background is given for Theodorsen, Loewy, Wagner unsteady aerodynamic theories and Pitt-Peters and Peters-He inflow theories. In addition, derivation of the simple beam theory is explained with the expansion methods of Rayleigh-Ritz and Galerkin. Three different solution types; k-method, modified k-method and p-method are studied based on the aerodynamic theory implemented. The flutter analysis results are verified and compared with the results given in the literature. The fixed wing analyses are validated with Goland’s fixed wing results, rotary wing analyses are validated both with helicopter blade and wind turbine blade analyses results. Case studies are performed to investigate the effects of the shear center and center of gravity locations and the forward velocity of the helicopter on the flutter analysis results.