Date of Award

Fall 2007

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical & Aerospace Engineering

Program/Concentration

Aerospace Engineering

Committee Director

Chuh Mei

Committee Member

Jen-Kuang Huang

Committee Member

Brett Newman

Call Number for Print

Special Collections; LD4331.E535 K56 2007

Abstract

Suppression of nonlinear panel flutter at supersonic speeds has been investigated traditionally with system equations of motion in terms of in vacuo modal coordinates. For isotropic and symmetrically laminated orthotropic composite plates, the limit-cycle oscillations converged with six in vacuo natural modes at zero yaw angle. However, as laminated composite plates undergo the effect of an arbitrary yawed flow angle, complicated characteristics emerge when increasing the required in vacuo natural modes for an analysis of limit-cycle oscillations. In order to design an effective controller, the large number of modes should be reduced. As a result, the small number of modes produces the capability to alleviate the costly computational effort in designing controllers for suppression of nonlinear panel flutter. In the present study, aeroelastic modes that provide the reduced order basis are utilized for panel limit-cycle motion. Two or six to seven aeroelastic modes are implemented for developing an active controller of panel flutter with isotropic and anisotropic laminated composite plates at zero or non-zero yaw angle, respectively. Along with the aeroelastic modal equations of lesser number, a linear quadratic regulator, which is one of the output feedback controllers, is constructed to suppress nonlinear panel flutter. An added extended Kalman filter compensates for the nonlinearity of structural motion resulting by updating the system information on-line. The norms of feedback control gain matrix and the norms of Kalman filter estimation gain matrix are employed for the optimal placement of PZT5A or Macro-Fiber Composite piezoelectric actuators and sensors. Numerical results show that the designed controller based on aeroelastic modal coordinates can suppress the large-amplitude panel nonlinear flutter response. The maximum flutter-free dynamic pressure for isotropic and composite plates is evaluated to measure how much the performance is improved.

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DOI

10.25777/snjv-wz89

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