Eventos Anais de eventos
DINAME 2023
XIX International Symposium on Dynamic Problems of Mechanics
Time domain aeroelastic analysis of the Pre-Pazy and Pazy Wings
Submission Author:
João Pedro Tavares Pereira dos Santos , BA
Co-Authors:
João Pedro Tavares Pereira dos Santos, Guilherme Ribeiro Begnini, Flavio D. Marques
Presenter: João Pedro Tavares Pereira dos Santos
doi://10.26678/ABCM.DINAME2023.DIN2023-0136
Abstract
Aeroelastic analyses are performed either in time or frequency domains. Frequency domain analyses have the advantage of providing a fast computation of the flutter speed and are more widespread. Their results are presented in the so-called velocity-damping-frequency (V-g-f) plots, which shows the evolution of the natural frequency and damping ratio of each vibration mode as a function of airspeed. This way, the flutter speed (where zero damping occurs) can be determined with precision. On the other hand, time domain analyses allow the inclusion of different types of nonlinearities in the simulations, with the price of being more time consuming. Their results consist of time histories whose vibration amplitudes should be visually inspected to find a constant amplitude situation (zero damping condition). This paper presents a time domain aeroelastic analysis of the Pre-Pazy and Pazy wings, presented on the Large Deflections Working Group of the Third Aeroelastic Prediction Workshop. Time domain results are then used to generate V-g-f plots through modal parameter identification. For the structural dynamics modeling the classical beam theory (Euler-Bernoulli) has been applied, and the natural frequencies and mode shapes were obtained via the Finite Element Method (FEM). For the aerodynamic modeling, the Unsteady Vortex Lattice Method (UVLM) was used, which is a three-dimensional aerodynamic model based on a potential flow formulation. The structural and aerodynamic models are coupled using a surface splines interpolation method, and the movement equation is solved iteratively on a time-domain basis, applying a predictor-corrector method. The frequency spectrum of each time response serves as input to the modal parameter identification method, which uses the Least Squares Complex Frequency estimator (LSCF). The structural and aeroelastic results of those wings are evaluated. It was possible to obtain very clear V-g-f plots, with a precise identification of flutter speeds, for all tested cases. The influence of the wing skin on the flutter speed results was assessed.
Keywords
Aeroelasticity, Unsteady Vortex Lattice Method, Finite Element Method, System Identification, Flutter
