Loading...

Aeroelastic Analysis of a Complete Aircraft Via State Space Modeling

Ghobadi, Amir Hossein | 2016

360 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 48501 (45)
  4. University: Sharif University of Technology
  5. Department: Aerospace Engineering
  6. Advisor(s): Keshavarz Haddad, Gholamreza
  7. Abstract:
  8. This dissertation presents aeroelastic stability analysis (flutter) pertinent to the complete flexible aircraft based on analytical dynamics, structural dynamics and aerodynamics. The unified formulation is based on fundamental principles and incorporates in a natural manner both rigid body motions of the aircraft as a whole and elastic deformations of the flexible components (fuselage, wing and empennage), as well as the aerodynamic, propulsion and gravity forces. The aircraft motion is described in terms of three translations and three rotations of a reference frame attached to the undeformed fuselage, and acting as aircraft body axes, and elastic displacements of each of the flexible components relative to corresponding body axes. For separation of variables and convertion of partial differential equations into ordinary differential equations, Ritz approximation is used. After separation of variables, the formulation consists of six ordinary differential equations for the rigid body motions and one set of ordinary differential equations for each elastic displacement. System of equations are nonlinear because of the flight dynamics variables. Perturbation approach is used for solving nonlinear system of equations. Perturbation approach permits division of the problem into a nonlinear “zero-order problem” for the rigid body motions, corresponding to flight dynamics, and a linear “first-order problem” for the elastic deformations and perturbations in the rigid body translations and rotations. Two kind of aerodynamics methods is used. A quasi-steady Aerodynamics for solving “zero-order problem” and unsteady aerodynamics with Jones approximation for solving “first-order problem”and stability analysis (flutter). For a certain rang of velocities, by using eigenvalue analysis of system of equations, flutter speed has been found. Finally, the result has been compared with results of the MSC/NASTRAN software
  9. Keywords:
  10. Aeroelasticity ; Flight Dynamics ; Flexible Aircraft ; Perturbation Method ; State Space ; Complete Flexible Aircraft ; Structural Dynamics

 Digital Object List

 Bookmark

No TOC