C. Pasquali, N. Spyropoulos, R. Leibbrandt, M. Gennaretti, V.A. Riziotis, S. Radler, G. Bernardini, G. Papadakis

In the present work, a non-standard procedure for aeroelastic stability assessment of rotors is proposed, it exploits the potentialities of the new multi-fidelity comprehensive rotorcraft simulation tool CORAL. This procedure uses a system identification approach to obtain a data-derived, tridimensional unsteady aerodynamic linearised model to couple with the linearised structural dynamics of the rotor. The linearised aerodynamic model is obtained from suited chirp perturbations of the elastic degrees of freedom of the blade about a steady trimmed solution, followed by a rational approximation of the transfer function matrix, which allows you to account for the aerodynamic hidden states. The rotor structural model is obtained through an analytical linearization of the non-linear multi-body dynamic equations, where the blades are modelled as assemblies of full stiffness matrix Timoshenko beams discretised through FEM elements. Once the linearised aeroelastic system is assembled, it is expressed in a state-space form, and a generalised eigenproblem is solved to evaluate the rotor stability margin. The Sharpe experimental campaign of 1986, dealing with the stability analysis of a hovering rotor, has been chosen as a benchmark for the first validation of the proposed methodology. The experimental lead-lag damping coefficients are successfully compared with numerical ones, computed through the CORAL mid-fidelity Lifting-Line/free-wake aerodynamic solver.

49th European Rotorcraft Forum 2023, Bückeburg, 2023

Conference Paper

englisch

21,0 x 29,7 cm, 9 Pages

DGLR-Bericht, 2023, 2023-01, 49th European Rotorcraft Forum 2023 - Proceedings; S.1-9; 2023; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V., Bonn

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2023