《MECHANICS OF AIRCRAFT STRUCTURES》求取 ⇩

1 Characteristics of Aircraft Structures and Materials1

1.1 Introduction1

1.2 Basic Structural Elements in Aircraft Structure2

1.2.1 Axial Member2

1.2.2 Shear Panel3

1.2.3 Bending Member (Beam)4

1.2.4 Torsion Member5

1.3 Wing and Fuselage7

1.3.1 Load Transfer7

1.3.2 Wing Structure9

1.3.3 Fuselage10

1.4 Aircraft Materials11

Problems15

2 Introduction to Elasticity17

2.1 Concept of Displacement17

2.2 Strain19

2.3 Stress24

2.4 Equations of Equilibrium in a Nonuniform Stress Field26

2.5 Principal Stresses27

2.5.1 Shear Stress32

2.5.2 Revisit of Transformation of Stress34

2.6 Linear Stress-Strain Relations36

2.6.1 Strains Induced by Normal Stress36

2.6.2 Strains Induced by Shear Stress39

2.6.3 3-D Stress-Strain Relations40

2.7 Elastic Strain Energy44

2.8 Plane Elasticity46

2.8.1 Stress-Strain Relations for Plane Isotropic Solids47

2.8.2 Stress-Strain Relations for Orthotropic Solids in Plane Stress50

2.8.3 Governing Equations51

2.8.4 Solution by Airy Stress Function for Plane Isotropic Solids52

Problems53

3 Torsion57

3.1 Torsion of Uniform Bars57

3.2 Bars with Circular Cross-Sections63

3.3 Bars with Narrow Rectangular Cross-Sections65

3.4 Closed Single-Cell Thin-Walled Sections69

3.5 Multicell Thin-Walled Sections79

Problems83

4 Bending and Flexural Shear87

4.1 Derivation of the Simple (Bernoulli-Euler) Beam Equation87

4.2 Bidirectional Bending92

4.3 Transverse Shear Stress due to Transverse Force in Symmetric Sections97

4.3.1 Narrow Rectangular Cross-Section98

4.3.2 General Symmetric Sections100

4.3.3 Wide-Flange Beam102

4.3.4 Stiffener-Web Sections103

Problems104

5 Flexural Shear Flow in Thin-Walled Sections107

5.1 Flexural Shear Flow in Open Thin-Walled Sections107

5.1.1 Symmetric Thin-Walled Sections108

5.1.2 Unsymmetric Thin-Walled Sections113

5.1.3 Multiple Shear Flow Junctions115

5.1.4 Selection of Shear Flow Contour117

5.2 Shear Center in Open Sections117

5.3 Closed Thin-Walled Sections and Combined Flexural and Torsional Shear Flow124

5.3.1 Shear Center125

5.3.2 Statically Determinate Shear Flow129

5.4 Multicell Closed Sections132

Problems136

6 Failure Criteria for Isotropic Materials141

6.1 Strength Criteria for Brittle Materials141

6.1.1 Maximum Principal Stress Criterion142

6.1.2 Coulomb-Mohr Criterion142

6.2 Yield Criteria for Ductile Materials145

6.2.1 Maximum Shear Stress Criterion (Tresca Yield Criterion) in Plane Stress145

6.2.2 Maximum Distortion Energy Criterion (von Mises Yield Criterion)147

6.3 Fracture Mechanics151

6.3.1 Stress Concentration151

6.3.2 Concept of Cracks and Strain Energy Release Rate152

6.3.3 Fracture Criterion154

6.4 Stress Intensity Factor159

6.4.1 Symmetric Loading (Mode I Fracture)159

6.4.2 Antisymmetric Loading (Mode II Fracture)162

6.4.3 Relation between K and G164

6.4.4 Mixed Mode Fracture169

6.5 Fatigue Failure169

6.5.1 Constant Stress Amplitude170

6.5.2 S-N Curves171

6.5.3 Variable Amplitude Loading171

6.6 Fatigue Crack Growth172

Problems174

7 Elastic Buckling179

7.1 Eccentrically Loaded Beam-Column179

7.2 Elastic Buckling of Straight Bars181

7.2.1 Pinned-Pinned Bar183

7.2.2 Clamped-Free Bar185

7.2.3 Clamped-Pinned Bar187

7.2.4 Clamped-Clamped Bar188

7.2.5 Effective Length of Buckling190

7.3 Initial Imperfection191

7.4 Postbuckling Behavior193

7.5 Bar of Unsymmetric Section199

7.6 Torsional-Flexural Buckling of Thin-Walled Bars202

7.6.1 Nonuniform Torsion202

7.6.2 Torsional Buckling--Doubly Symmetric Section205

7.6.3 Torsional-Flexural Buckling208

7.7 Elastic Buckling of Flat Plates212

7.7.1 Governing Equation for Flat Plates212

7.7.2 Cylindrical Bending215

7.7.3 Buckling of Rectangular Plates216

7.7.4 Buckling under Shearing Stresses220

7.8 Local Buckling of Open Sections220

Problems223

8 Analysis of Composite Laminates227

8.1 Plane Stress Equations for Composite Lamina227

8.2 Off-Axis Loading233

8.3 Notation for Stacking Sequence in Laminates236

8.4 Symmetric Laminate under In-Plane Loading238

8.5 Effective Moduli for Symmetric Laminates241

8.6 Laminar Stresses243

8.7 [±45??] Laminate246

Problems248

Index251