Design and Analysis of Composite Structures With Applications to Aerospace Structures

About the Author xi

Series Preface xiii

Preface to First Edition xv

Preface to Second Edition xix

1 Applications of Advanced Composites in Aircraft Structures 1

References 7

2 Cost of Composites: a Qualitative Discussion 9

2.1 Recurring Cost 10

2.2 Nonrecurring Cost 18

2.3 Technology Selection 20

2.4 Summary and Conclusions 27

Exercises 30

References 31

3 Review of Classical Laminated Plate Theory 33

3.1 Composite Materials: Definitions, Symbols and Terminology 33

3.2 Constitutive Equations in Three Dimensions 35
3.2.1 Tensor Transformations 38

3.3 Constitutive Equations in Two Dimensions: Plane Stress 40

Exercises 52

References 53

4 Review of Laminate Strength and Failure Criteria 55

4.1 Maximum Stress Failure Theory 57

4.2 Maximum Strain Failure Theory 58

4.3 Tsai-Hill Failure Theory 58

4.4 Tsai-Wu Failure Theory 59

4.5 Puck Failure Theory 59

4.6 Other Failure Theories 61

References 62

5 Composite Structural Components and Mathematical Formulation 65

5.1 Overview of Composite Airframe 65
5.1.1 The Structural Design Process: The Analyst's Perspective 66
5.1.2 Basic Design Concept and Process/Material Considerations for Aircraft Parts 71
5.1.3 Sources of Uncertainty: Applied Loads, Usage and Material Scatter 74
5.1.3.1 Knowledge of Applied Loads 75
5.1.3.2 Variability in Usage 75
5.1.3.3 Material Scatter 75
5.1.4 Environmental Effects 77
5.1.5 Effect of Damage 78
5.1.6 Design Values and Allowables 80
5.1.7 Additional Considerations of the Design Process 83

5.2 Governing Equations 84
5.2.1 Equilibrium Equations 84
5.2.2 Stress-Strain Equations 86
5.2.3 Strain-Displacement Equations 87
5.2.4 von Karman Anisotropic Plate Equations for Large Deflections 88

5.3 Reductions of Governing Equations: Applications to Specific Problems 94
5.3.1 Composite Plate under Localized In-Plane Load 94
5.3.2 Composite Plate under Out-of-Plane Point Load 105

5.4 Energy Methods 108
5.4.1 Energy Expressions for Composite Plates 109
5.4.1.1 Internal Strain Energy U 110
5.4.1.2 External Work W 113

Exercises 115

References 122

6 Buckling of Composite Plates 125

6.1 Buckling of Rectangular Composite Plate under Biaxial Loading 125

6.2 Buckling of Rectangular Composite Plate under Uniaxial Compression 129
6.2.1 Uniaxial Compression, Three Sides Simply Supported, OneSideFree 131

6.3 Buckling of Rectangular Composite Plate under Shear 133

6.4 Buckling of Long Rectangular Composite Plates under Shear 136

6.5 Buckling of Rectangular Composite Plates under Combined Loads 138

6.6 Design Equations for Different Boundary Conditions and Load Combinations 145

Exercises 145

References 152

7 Post-Buckling 153

7.1 Post-Buckling Analysis of Composite Panels under Compression 157
7.1.1 Application: Post-Buckled Panel under Compression 165

7.2 Post-Buckling Analysis of Composite Plates under Shear 168
7.2.1 Post-Buckling of Stiffened Composite Panels under Shear 172
7.2.1.1 Application: Post-Buckled Stiffened Fuselage Skin under Shear 177
7.2.2 Post-Buckling of Stiffened Composite Panels under Combined Uniaxial and Shear Loading 180

Exercises 181

References 187

8 Design and Analysis of Composite Beams 189

8.1 Cross-Section Definition Based on Design Guidelines 189

8.2 Cross-Sectional Properties 193

8.3 Column Buckling 199

8.4 Beam on an Elastic Foundation under Compression 200

8.5 Crippling 205
8.5.1 One-Edge-Free (OEF) Crippling 207
8.5.2 No-Edge-Free (NEF) Crippling 211
8.5.3 Crippl