Introduction to Aircraft Aeroelasticity and Loads

Introduction to Aircraft Aeroelasticity and Loads, Second Edition is an updated new edition offering comprehensive coverage of the main principles of aircraft aeroelasticity and loads. For ease of reference, the book is divided into three parts and begins by reviewing the underlying disciplines of vibrations, aerodynamics, loads and control, and then goes on to describe simplified models to illustrate aeroelastic behaviour and aircraft response and loads for the flexible aircraft before introducing some more advanced methodologies. Finally, it explains how industrial certification requirements for aeroelasticity and loads may be met and relates these to the earlier theoretical approaches used.

Key features of this new edition include:

• Uses a unified simple aeroelastic model throughout the book

• Major revisions to chapters on aeroelasticity

• Updates and reorganisation of chapters involving Finite Elements

• Some reorganisation of loads material

• Updates on certification requirements

• Accompanied by a website containing a solutions manual, and MATLAB® and SIMULINK® programs that relate to the models used

Introduction to Aircraft Aeroelasticity and Loads, Second Edition is a must-have reference for researchers and practitioners working in the aeroelasticity and loads fields, and is also an excellent textbook for senior undergraduate and graduate students in aerospace engineering.

Autorentext

Jan R. Wright
University of Manchester, UK

Jonathan E. Cooper
University of Bristol, UK

Zusammenfassung

Introduction to Aircraft Aeroelasticity and Loads, Second Edition is an updated new edition offering comprehensive coverage of the main principles of aircraft aeroelasticity and loads. For ease of reference, the book is divided into three parts and begins by reviewing the underlying disciplines of vibrations, aerodynamics, loads and control, and then goes on to describe simplified models to illustrate aeroelastic behaviour and aircraft response and loads for the flexible aircraft before introducing some more advanced methodologies. Finally, it explains how industrial certification requirements for aeroelasticity and loads may be met and relates these to the earlier theoretical approaches used.

Key features of this new edition include:

• Uses a unified simple aeroelastic model throughout the book
• Major revisions to chapters on aeroelasticity
• Updates and reorganisation of chapters involving Finite Elements
• Some reorganisation of loads material
• Updates on certification requirements
• Accompanied by a website containing a solutions manual, and MATLAB® and SIMULINK® programs that relate to the models used
  Introduction to Aircraft Aeroelasticity and Loads, Second Edition is a must-have reference for researchers and practitioners working in the aeroelasticity and loads fields, and is also an excellent textbook for senior undergraduate and graduate students in aerospace engineering.

Inhalt

Series Preface xxi

Preface to the Second Edition xxiii

Preface to the First Edition xxv

Abbreviations xxix

Introduction 1

PART I BACKGROUND MATERIAL 7

1 Vibration of Single Degree of Freedom Systems 9

1.1 Setting up Equations of Motion for SDoF Systems 9

1.2 Free Vibration of SDoF Systems 11

1.3 Forced Vibration of SDoF Systems 13

1.4 Harmonic Forced Vibration Frequency Response Functions 14

1.5 Transient/Random Forced Vibration Time Domain Solution 17

1.6 Transient Forced Vibration Frequency Domain Solution 21

1.7 Random Forced Vibration Frequency Domain Solution 23

1.8 Examples 24

2 Vibration of Multiple Degree of Freedom Systems 27

2.1 Setting up Equations of Motion 27

2.2 Undamped Free Vibration 29

2.3 Damped Free Vibration 31

2.4 Transformation to Modal Coordinates 34

2.5 Two-DoF Rigid Aircraft in Heave and Pitch 38

2.6 'FreeFree' Systems 40

2.7 Harmonic Forced Vibration 41

2.8 Transient/Random Forced Vibration Time Domain Solution 43

2.9 Transient Forced Vibration Frequency Domain Solution 44

2.10 Random Forced Vibration Frequency Domain Solution 44

2.11 Examples 45

3 Vibration of Continuous Systems Assumed Shapes Approach 49

3.1 Continuous Systems 49

3.2 Modelling Continuous Systems 49

3.3 Elastic and Flexural Axes 51

3.4 RayleighRitz 'Assumed Shapes' Method 52

3.5 Generalized Equations of Motion Basic Approach 53

3.6 Generalized Equations of Motion Matrix Approach 58

3.7 Generating Whole Aircraft 'FreeFree' Modes from 'Branch' Modes 61

3.8 Whole Aircraft 'FreeFree' Modes 64

3.9 Examples 65

4 Introduction to Steady Aerodynamics 69

4.1 The Standard Atmosphere 69

4.2 Effect of Air Speed on Aerodynamic Characteristics 71

4.3 Flows and Pressures Around a Symmetric Aerofoil 73

4.4 Forces on an Aerofoil 74

4.5 Variation of Lift for an Aerofoil at an Angle of Incidence 76

4.6 Pitching Moment Variation and the Aerodynamic Centre 77

4.7 Lift on a Three-dimensional Wing 78

4.8 Drag on a Three-dimensional Wing 82

4.9 Control Surfaces 83

4.10 Transonic Flows 84

4.11 Examples 85

5 Introduction to Loads 87

5.1 Laws of Motion 88

5.2 D'Alembert's Principle Inertia Forces and Couples 90

5.3 External Loads Applied and Reactive 94

5.4 Free Body Diagrams 95

5.5 Internal Loads 96

5.6 Internal Loads for a Continuous Member 96

5.7 Internal Loads for a Discretized Member 101

5.8 Intercomponent Loads 103

5.9 Obtaining Stresses from Internal Loads Structural Members with Simple Load Paths 103

5.10 Examples 104

6 Introduction to Control 109

6.1 Open and Closed Loop Systems 109

6.2 Laplace Transforms 110

6.3 Modelling of Open and Closed Loop Systems using Laplace and Frequency Domains 112

6.4 Stability of Systems 114

6.5 PID Control 121

6.6 Examples 122

PART II INTRODUCTION TO AEROELASTICITY AND LOADS 123

7 Static Aeroelasticity Effect of Wing Flexibility on Lift Distribution and Divergence 125

7.1 Static Aeroelastic Behaviour of a Two-dimensional Rigid Aerofoil with a Torsional Spring Attachment 126

7.2 Static Aeroelastic Behaviour of a Fixed Root Flexible Wing 130

7.3 Effect of Trim on Static Aeroelastic Behaviour 133

7.4 Effect of Wing Sweep on Static Aeroelastic Behaviour 137

7.5 Examples 142

8 Static Aeroelasticity Effect of Wing Flexibility on Control Effectiveness 143

8.1 Rolling Effectiveness of a Flexible Wing Fixed Wing Root Case 144 8.2 Rolling Effectiveness of a Flex...