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| Author(s): |
Carlos De Marqui Júnior
Total Authors: 1
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| Document type: | Doctoral Thesis |
| Press: | São Carlos. , gráficos, ilustrações, tabelas. |
| Institution: | Universidade de São Paulo (USP). Escola de Engenharia de São Carlos (EESC/SBD) |
| Defense date: | 2004-08-13 |
| Examining board members: |
Eduardo Morgado Belo;
Luiz Carlos Sandoval Góes;
Flavio Donizeti Marques;
Hugo Borelli Resende;
Fernando Garcia Santoro
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| Advisor: | Eduardo Morgado Belo |
| Field of knowledge: | Engineering - Aerospace Engineering |
| Indexed in: | Banco de Dados Bibliográficos da USP-DEDALUS |
| Location: | Universidade de São Paulo. Biblioteca da Escola de Engenharia de São Carlos; EESC/TESE 1857 |
| Abstract | |
Flutter is a dynamic aeroelastic instability that involves the interaction of aerodynamic, elastic and inertial forces. This instability may occur in aircraft surfaces, like wings, which will present a self-sustained oscillatory behaviour and possible structural problems if not suppressed. One of the classical types of flutter involves the coupling of bending and torsion vibration modes. This binary type of flutter is known as flexural-torsional flutter. A flexible mount system is developed for flexural-torsional flutter tests with rigid wings in wind tunnels. The design procedure of this mount system is based in simulations performed with a finite element model which results are tested in simulations performed with an Aeroelastic model formulated to simulate the aeroelastic behaviour of the experimental system. Then, to verify the analytical results, an experimental modal analysis is performed and mode shapes and frequencies are identified using the Eigensystem Realization Algorithm. After this, some wind tunnel tests are performed to verify flutter achievement, for flutter characterization and for flutter identification. The development of this experimental system allows the study and application of active control laws for active flutter suppression, which is the main goal of this work. A state feedback controller for active flutter suppression is designed using the aeroelastic model previously developed. This controller is initially tested in simulations and, then, wind-tunnel experiments are performed. The goal is to suppress flutter and to maintain the stability of the closed loop system. The wind tunnel model is a rigid rectangular wing with a NACA 0012 airfoil section with a trailing edge control surface used as actuator. (AU) | |