Aircraft Structures For Engineering StudentsPDF电子书下载

PART A FUNDAMENTALS OF STRUCTURAL ANALYSIS 3

Section A1 Elasticity 3

CHAPTER 1 Basic elasticity 5

1.1 Stress 5

1.2 Notation for forces and stresses 7

1.3 Equations of equilibrium 9

1.4 Plane stress 11

1.5 Boundary conditions 11

1.6 Determination of stresses on inclined planes 12

1.7 Principal stresses 15

1.8 Mohr’s circle of stress 17

1.9 Strain 22

1.10 Compatibility equations 25

1.11 Plane strain 26

1.12 Determination of strains on inclined planes 27

1.13 Principal strains 29

1.14 Mohr’s circle of strain 30

1.15 Stress-strain relationships 30

1.16 Experimental measurement of surface strains 37

Reference 43

Problems 43

CHAPTER 2 Two-dimensional problems in elasticity 47

2.1 Two-dimensional problems 47

2.2 Stress functions 49

2.3 Inverse and semi-inverse methods 50

2.4 St.Venant’s principle 56

2.5 Displacements 57

2.6 Bending of an end-loaded cantilever 58

Reference 63

Problems 63

CHAPTER 3 Torsion of solid sections 69

3.1 Prandtl stress function solution 69

3.2 St.Venant warping function solution 81

3.3 The membrane analogy 82

3.4 Torsion of a narrow rectangular strip 84

References 86

Problems 87

Section A2 Virtual work，energy，and matrix methods 89

CHAPTER 4 Virtual work and energy methods 91

4.1 Work 91

4.2 Principle of virtual work 92

4.3 Applications of the principle of virtual work 106

Reference 117

Problems 118

CHAPTER 5 Energy methods 123

5.1 Strain energy and complementary energy 123

5.2 Principle of the stationary value of the total complementary energy 125

5.3 Application to deflection problems 126

5.4 Application to the solution of statically indeterminate systems 135

5.5 Unit load method 152

5.6 Flexibility method 155

5.7 Total potential energy 160

5.8 Principle of the stationary value of the total potential energy 161

5.9 Principle of superposition 164

5.10 Reciprocal theorem 164

5.11 Temperature effects 168

References 171

Further reading 171

Problems 171

CHAPTER 6 Matrix methods 183

6.1 Notation 184

6.2 Stiffness matrix for an elastic spring 185

6.3 Stiffness matrix for two elastic springs in line 186

6.4 Matrix analysis of pin-jointed frameworks 189

6.5 Application to statically indeterminate frameworks 196

6.6 Matrix analysis of space frames 196

6.7 Stiffness matrix for a uniform beam 198

6.8 Finite element method for continuum structures 205

References 223

Further reading 223

Problems 223

Section A3 Thin plate theory 231

CHAPTER 7 Bending of thin plates 233

7.1 Pure bending of thin plates 233

7.2 Plates subjected to bending and twisting 236

7.3 Plates subjected to a distributed transverse load 240

7.4 Combined bending and in-plane loading of a thin rectangular plate 250

7.5 Bending of thin plates having a small initial curvature 254

7.6 Energy method for the bending of thin plates 255

Further reading 263

Problems 263

Section A4 Structural instability 267

CHAPTER 8 Columns 269

8.1 Euler buckling of columns 269

8.2 Inelastic buckling 275

8.3 Effect of initial imperfections 280

8.4 Stability of beams under transverse and axial loads 283

8.5 Energy method for the calculation of buckling loads in columns 286

8.6 Flexural-torsional buckling of thin-walled columns 290

References 302

Problems 302

CHAPTER 9 Thin plates 311

9.1 Buckling of thin plates 311

9.2 Inelastic buckling of plates 314

9.3 Experimental determination of the critical load for a flat plate 316

9.4 Local instability 316

9.5 Instability of stiffened panels 317

9.6 Failure stress in plates and stiffened panels 319

9.7 Tension field beams 323

References 339

Problems 340

Section A5 Vibration of structures 345

CHAPTER 10 Structural vibration 347

10.1 Oscillation of mass-spring systems 347

10.2 Oscillation of beams 356

10.3 Approximate methods for determining natural frequencies 361

Problems 364

PART B ANALYSIS OF AIRCRAFT STRUCTURES 371

Section B1 Principles of stressed skin construction 371

CHAPTER 11 Materials 373

11.1 Aluminum alloys 373

11.2 Steel 375

11.3 Titanium 376

11.4 Plastics 377

11.5 Glass 377

11.6 Composite materials 377

11.7 Properties of materials 379

Problems 394

CHAPTER 12 Structural components of aircraft 397

12.1 Loads on structural components 397

12.2 Function of structural components 399

12.3 Fabrication of structural components 404

12.4 Connections 409

Reference 415

Problems 415

Section B2 Airworthiness and airframe loads 419

CHAPTER 13 Airworthiness 421

13.1 Factors of safety-flight envelope 421

13.2 Load factor determination 423

Reference 426

Problems 426

CHAPTER 14 Airframe loads 427

14.1 Aircraft inertia loads 427

14.2 Symmetric maneuver loads 433

14.3 Normal accelerations associated with various types of maneuver 438

14.4 Gust loads 442

References 450

Problems 450

CHAPTER 15 Fatigue 457

15.1 Safe life and fail-safe structures 457

15.2 Designing against fatigue 458

15.3 Fatigue strength of components 459

15.4 Prediction of aircraft fatigue life 465

15.5 Crack propagation 471

References 478

Further reading 478

Problems 478

Section B3 Bending，shear and torsion of thin-walled beams 481

CHAPTER 16 Bending of open and closed，thin-walled beams 483

16.1 Symmetrical bending 484

16.2 Unsymmetrical bending 492

16.3 Deflections due to bending 499

16.4 Calculation of section properties 514

16.5 Applicability of bending theory 523

16.6 Temperature effects 523

Reference 527

Problems 527

CHAPTER 17 Shear of beams 537

17.1 General stress，strain，and displacement relationships for open and single-cell closed section thin-walled beams 537

17.2 Shear of open section beams 541

17.3 Shear of closed section beams 550

Reference 559

Problems 559

CHAPTER 18 Torsion of beams 569

18.1 Torsion of closed section beams 569

18.2 Torsion of open section beams 579

Problems 585

CHAPTER 19 Combined open and closed section beams 593

19.1 Bending 593

19.2 Shear 595

19.3 Torsion 598

Problems 603

CHAPTER 20 Structural idealization 605

20.1 Principle 605

20.2 Idealization of a panel 606

20.3 Effect of idealization on the analysis of open and closed section beams 608

20.4 Deflection of open and closed section beams 620

Problems 623

Section B4 Stress analysis of aircraft components 629

CHAPTER 21 Wing spars and box beams 631

21.1 Tapered wing spar 631

21.2 Open and closed section beams 635

21.3 Beams having variable stringer areas 640

Problems 645

CHAPTER 22 Fuselages 649

22.1 Bending 649

22.2 Shear 651

22.3 Torsion 653

22.4 Cut-outs in fuselages 655

Problems 660

CHAPTER 23 Wings 663

23.1 Three-boom shell 663

23.2 Bending 664

23.3 Torsion 665

23.4 Shear 670

23.5 Shear center 677

23.6 Tapered wings 677

23.7 Deflections 680

23.8 Cut-outs in wings 681

Problems 689

CHAPTER 24 Fuselage frames and wing ribs 697

24.1 Principles of stiffener/web construction 697

24.2 Fuselage frames 702

24.3 Wing ribs 703

Problems 707

CHAPTER 25 Laminated composite structures 709

25.1 Elastic constants of a simple lamina 709

25.2 Stress-strain relationships for an orthotropic ply （macro approach） 715

25.3 Laminates 724

25.4 Thin-walled composite beams 740

References 753

Problems 753

Section B5 Structural and loading discontinuities 761

CHAPTER 26 Closed section beams 763

26.1 General aspects 763

26.2 Shear stress distribution at a built-in end of a closed section beam 764

26.3 Thin-walled rectangular section beam subjected to torsion 770

26.4 Shear lag 778

Reference 795

Problems 795

CHAPTER 27 Open section beams 805

27.1 I-section beam subjected to torsion 805

27.2 Torsion of an arbitrary section beam 807

27.3 Distributed torque loading 817

27.4 Extension of the theory to allow for general systems of loading 819

27.5 Moment couple （bimoment） 822

References 825

Problems 825

Section B6 Introduction to aeroelasticity 831

CHAPTER 28 Wing problems 833

28.1 Types of problem 833

28.2 Load distribution and divergence 834

28.3 Control effectiveness and reversal 840

28.4 Introduction to “flutter” 846

References 853

Problems 853

Appendix：Design of a rear fuselage 857

Index 885