Introductory Guide on the Design of Aerospace Structures
Developed from a course taught at Concordia University for more than 20 years, Principles of Aeroelasticity utilizes the author’s extensive teaching experience to immerse undergraduate and first-year graduate students into this very specialized subject. Ideal for coursework or self-study, this detailed examination introduces the concepts of aeroelasticity, describes how aircraft lift structures behave when subjected to aerodynamic loads, and finds its application in aerospace, civil, and mechanical engineering.
The book begins with a discussion on static behavior, and moves on to static instability and divergence, dynamic behavior leading up to flutter, and fluid structure interaction problems. It covers classical approaches based on low-order aerodynamic models and provides a rationale for adopting certain aeroelastic models. The author describes the formulation of discrete models as well as continuous structural models. He also provides approximate methods for solving divergence, flutter, response and stability of structures, and addresses non-aeroelastic problems in other areas that are similar to aeroelastic problems.
Topics covered include:
- The fundamentals of vibration theory
- Vibration of single degree of freedom and two degrees of freedom systems
- Elasticity in the form of an idealized spring element
- Repetitive motion
- Flutter phenomenon
- Classical methods, Rayleigh-Ritz techniques, Galerkin’s technique, influential coefficient methods, and finite element methods
- Unsteady aerodynamics, and more
Introduction
Elementary Aerodynamics
General Concepts
The Joukowski Transformation for Airfoils
Dimensional Analysis of Force Experienced by a Solid Body in a Flow
Static Aeroelasticity
Introduction
Determination of Shear Center in a Thin-Walled Section
Divergence of a Lifting Surface
Introduction
Divergence of a Typical Section with a Control Surface
Introduction
Control Surface Reversal
Dynamic Aeroelasticity
Introduction
Vibration Theory
Damped Single DOF System
Energy Method
Sinusoidal Excitation
Periodic Force
Arbitrary Force
Two DOF System
Equations of Motion of a Two DOF Model of an Aircraft Wing
Quasi-Steady Aerodynamic Theory
Can Flutter Be Seen If Only Torsional Motion Is Considered?
Dynamics of Airfoil
Random Motion
One-Dimensional Aeroelastic Model of Airfoils
Introduction
Simple Torsion of a Bar
General Approximations for Aerodynamic Theory
Eigenvalue and Eigenfunction Approaches
Rolling of a Straight Wing
Introduction
Determination of Aerodynamic Influence Functions
Flutter of a Cantilever Wing
Introduction
Simple Bending of Beams
Stability of the Motion
Approximate Techniques of Modeling Continuous Systems
Influence Coefficient Method
Galerkin’s Method
Rayleigh-Ritz Method
Finite Element Method
Assembly of Finite Elements
Finite Element Representation of the Response and Flutter Problems
Elastic Foundation
Eigenfunctions and Eigenvalues
Nonairfoil Physical Problems
Divergence
Stall Flutter
Flutter and Buffeting of Bridges
Aeroelasticity of Turbomachinery Blades
Nonlinear Aeroelasticity
Generic Nonlinear Aeroelastic Behavior
One Degree of Freedom Nonlinear System: Divergence
One Degree of Freedom System: Dynamic Effects
Two Degrees of Freedom System: Dynamic Effects
Unsteady Aerodynamics
Introduction
Theodorsen’s Unsteady Thin-Airfoil Theory
Flutter Prediction via Assumed Modes
References
Biography
Rama Bhat is a professor of mechanical and industrial engineering at Concordia University, Montreal, Canada. His research areas include dynamics of structures, vibration of continuous systems, rotor dynamics, sound transmission into aircraft fuselage, dynamics of micro-electro-mechanical systems, ride dynamics and biodynamics. He has published widely and taught courses in the above areas. In particular, he has been teaching a course on the principles of aeroelasticity for over two decades. He was awarded the NASA Award for his contribution as a member of the team that developed the "PROSSS-Programming Structured Synthesis System" and is a Fellow of several technical societies.
