Symbols, Acronyms and Units ................................... xix
1 Introduction to Fatigue of Structures and Materials .......... 1
References ................................................... 9
Part I Fatigue under Constant-Amplitude Loading (Chapters 2-8)
2 Fatigue as a Phenomenon in the Material ..................... 13
2.1 Introduction ........................................... 13
2.2 Different phases of the fatigue life ................... 14
2.3 Crack initiation ....................................... 15
2.4 Crack growth ........................................... 18
2.5 The fatigue mechanism in more detail ................... 21
2.5.1 Crystallographic aspects ........................ 23
2.5.2 Crack initiation at inclusions .................. 25
2.5.3 Small cracks, crack growth barriers,
thresholds ...................................... 29
2.5.4 Number of crack nuclei .......................... 32
2.5.5 Surface effects ................................. 36
2.5.6 Crack growth and striations ..................... 39
2.5.7 Environmental effects ........................... 44
2.5.8 Cyclic tension and cyclic torsion ............... 47
2.6 Characteristic features of fatigue failures ............ 48
2.6.1 Microscopic characteristics ..................... 50
2.6.2 Macroscopic characteristics ..................... 51
2.7 Main topics of the present chapter ..................... 55
References .................................................. 56
3 Stress Concentration at Notches ............................. 59
3.1 Introduction ........................................... 59
3.2 Definition of Kt ....................................... 60
3.3 Analytical calculations on stress concentrations ....... 62
3.4 Effect of the notch geometry on Kt ..................... 69
3.5 Some additional aspects of stress concentrations ....... 76
3.6 Superposition of notches ............................... 80
3.7 Methods for the determination of stress
concentrations ......................................... 82
3.8 Main topics of the present chapter ..................... 86
References .................................................. 87
4 Residual Stress ............................................. 89
4.1 Introduction ........................................... 89
4.2 Different sources of residual stresses ................. 91
4.3 Measurements or calculations of residual stresses ...... 98
4.4 Estimation of the residual stress at a notch after a
high load .............................................. 99
4.5 How to remove residual stresses ....................... 102
4.6 Main topics of the present chapter .................... 103
References ................................................. 104
5 Stress Intensity Factors of Cracks ......................... 105
5.1 Introduction .......................................... 105
5.2 Different types of cracks ............................. 108
5.3 Definition of the stress intensity factor ............. 109
5.4 Examples of stress intensity factors .................. 111
5.5 К factors obtained by superposition ................... 122
5.6 Cracks with curved crack fronts ....................... 124
5.7 Crack opening and the state of stress ................. 127
5.8 Crack tip plasticity .................................. 130
5.9 Some energy considerations ............................ 133
5.10 Determination of stress intensity factors ............. 135
5.11 The similarity concept and the application of the
stress intensity factor К ............................. 136
5.12 Main topics of the present chapter .................... 138
References ................................................. 139
6 Fatigue Properties ......................................... 141
6.1 Introduction .......................................... 141
6.2 Description of fatigue properties of unnotched
material .............................................. 143
6.3 Some general aspects of the fatigue strength of
unnotched specimens ................................... 149
6.3.1 Relation between Sf and Su ..................... 149
6.3.2 Mean stress effects ............................ 150
6.3.3 The size effect for unnotched specimens ........ 153
6.3.4 Type of loading, tension, bending, torsion ..... 157
6.3.5 Combined loading ............................... 159
6.4 Low-cycle fatigue ..................................... 162
6.5 Main topics of the present chapter .................... 167
References ................................................. 168
7 The Fatigue Strength of Notched Specimens .................. 171
7.1 Introduction .......................................... 171
7.2 The fatigue limit of notched specimens at Sm = 0 ...... 173
7.2.1 The similarity principle and the notch
sensitivity .................................... 173
7.2.2 The size effect on the fatigue limit of
notched specimens .............................. 175
7.3 The fatigue limit of notched specimens for Sm > 0 ..... 182
7.4 Notch effect under cyclic torsion ..................... 188
7.5 Notch effect on the fatigue limit for combined
loading cases ......................................... 190
7.6 Significance of the surface finish .................... 192
7.7 Discussion on predictions of the fatigue limit ........ 195
7.8 The S-N curves of notched specimens ................... 202
7.9 The major topics of the present chapter ............... 206
References ................................................. 207
8 Fatigue Crack Growth. Analysis and Predictions ............. 209
8.1 Introduction .......................................... 209
8.2 Description of fatigue crack growth properties ........ 211
8.2.1 Test results ................................... 211
8.2.2 The stress intensity factor and the
similarity concept ............................. 212
8.2.3 Constant-Δ K tests ............................. 216
8.3 Fatigue crack growth regions .......................... 217
8.4 Crack closure ......................................... 225
8.4.1 Plasticity induced crack closure and Δ Keff .... 225
8.4.2 Plane strain/plane stress ...................... 230
8.4.3 Thickness effect on fatigue crack growth ....... 232
8.4.4 Other crack closure mechanisms ................. 233
8.5 Crack growth data of different materials .............. 234
8.6 Prediction of fatigue crack growth .................... 240
8.6.1 Some basic aspects ............................. 240
8.6.2 Crack growth predictions for through cracks .... 243
8.6.3 Crack growth prediction for part through
cracks ......................................... 248
8.6.4 A final comment ................................ 252
8.7 Major topics of the present chapter ................... 252
References ................................................. 253
Part II Load Spectra and Fatigue under Variable-Amplitude
Loading (Chapters 9-11)
9 Load Spectra ............................................... 259
9.1 Introduction .......................................... 259
9.2 Different types of loads on a structure in service .... 261
9.3 Description of load histories ......................... 267
9.4 Determination of load spectra ......................... 280
9.4.1 The qualitative approach ....................... 281
9.4.2 The quantitative approach ...................... 284
9.5 Service-simulation fatigue tests and load spectra ..... 287
9.6 Major aspects of the present chapter .................. 291
References ................................................. 292
10 Fatigue under Variable-Amplitude Loading ................... 295
10.1 Introduction .......................................... 296
10.2 The Miner rule ........................................ 297
10.2.1 Effect of load cycles with stress amplitudes
below the fatigue limit ........................ 299
10.2.2 Effect of notch root plasticity ................ 300
10.2.3 Crack length at failure ........................ 302
10.2.4 What is basically wrong with the Miner rule? ... 302
10.3 Results of fatigue tests under VA loading ............. 306
10.4 Alternative fatigue life prediction methods for VA
loading ............................................... 313
10.4.1 Damage calculations and extrapolation of S-N
curves below the fatigue limit ................. 313
10.4.2 The relative Miner rule ........................ 316
10.4.3 Strain history prediction model ................ 316
10.4.4 Predictions based on service-simulation
fatigue tests .................................. 318
10.5 Discussion of fatigue life predictions for VA
loading ............................................... 323
10.5.1 Life estimates for a specific component and
the Miner rale ................................. 324
10.5.2 Considerations on the effect of the design
stress level ................................... 325
10.5.3 Comparison between different options for
design improvements ............................ 325
10.5.4 Comparison of different load spectra ........... 325
10.6 Major topics of the present chapter ................... 326
References ................................................. 327
11 Fatigue Crack Growth under Variable-Amplitude Loading ...... 329
11.1 Introduction .......................................... 329
11.2 Crack growth under simple VA-stress histories ......... 331
11.3 Crack growth under complex VA-stress histories ........ 344
11.4 Crack growth prediction models for VA loading ......... 351
11.4.1 Non-interaction model .......................... 352
11.4.2 Interaction models for prediction of fatigue
crack growth under VA loading .................. 353
11.5 Evaluation of prediction methods for fatigue crack
growth under VA-load histories ........................ 361
11.6 Major topics of the present chapter ................... 365
References ................................................. 366
Part III Fatigue Tests and Scatter (Chapters 12 and 13)
12 Fatigue and Scatter ........................................ 373
12.1 Introduction .......................................... 373
12.2 Sources of scatter .................................... 373
12.3 Description of scatter ................................ 375
12.4 Some practical aspects of scatter ..................... 385
12.5 Major topics of the present chapter ................... 392
References ................................................. 393
13 Fatigue Tests .............................................. 395
13.1 Introduction .......................................... 395
13.2 Purposes of fatigue test programs ..................... 396
13.3 Specimens ............................................. 397
13.4 Fatigue test procedures ............................... 402
13.5 Reporting about fatigue test results .................. 406
13.6 Aspects of crack growth measurements .................. 408
13.7 Main topics of this chapter ........................... 416
References ................................................. 416
Part IV Special Fatigue Conditions (Chapters 14-17)
14 Surface Treatments ......................................... 421
14.1 Introduction .......................................... 421
14.2 Aspects of surface treatments ......................... 422
14.3 Some practical aspects of surface treatments .......... 434
14.4 Summary of major topics of the present chapter ........ 435
References ................................................. 435
15 Fretting Corrosion ......................................... 437
15.1 Introduction .......................................... 437
15.2 The fretting corrosion mechanism ...................... 438
15.3 Effects on fretting corrosion ......................... 441
15.4 Methods to avoid fretting corrosion problems .......... 447
15.5 Topics of the present chapter ......................... 454
References ................................................. 455
16 Corrosion Fatigue .......................................... 457
16.1 Introduction .......................................... 457
16.2 Aspects of corrosion fatigue .......................... 459
16.2.1 Corrosion fatigue in gaseous environments ...... 462
16.2.2 Corrosion fatigue in liquid environments ....... 464
16.3 Practical aspects of corrosion fatigue ................ 472
16.4 A case history ........................................ 475
16.5 Topics of the present chapter ......................... 476
References ................................................. 477
17 High-Temperature and Low-Temperature Fatigue ............... 481
17.1 Introduction .......................................... 481
17.2 Two examples of high-temperature fatigue .............. 483
17.3 Fatigue properties at high temperatures ............... 487
17.4 Fatigue at low temperatures ........................... 490
17.5 Some general comments ................................. 494
References ................................................. 495
Part V Fatigue of Joints and Structures (Chapters 18-20)
18 Fatigue of Joints .......................................... 499
18.1 Introduction .......................................... 499
18.2 Fatigue of lugs ....................................... 501
18.3 Symmetric butt joints with rows of bolts or rivets .... 508
18.4 Bolts loaded in tension ............................... 511
18.5 Riveted and bolted joints with eccentricities ......... 517
18.6 Adhesive-bonded joints ................................ 527
18.7 General discussion on predictions of fatigue
properties of joints .................................. 529
18.8 Major topics of the present chapter ................... 531
References ................................................. 531
19 Fatigue of Welded Joints ................................... 535
19.1 Introduction .......................................... 535
19.2 Some general aspects .................................. 536
19.3 Geometry aspects of welds ............................. 538
19.4 Fatigue life considerations for СA loading ............ 545
19.5 Fatigue endurances of welded joints under VA
loading ............................................... 551
19.6 Two special cases ..................................... 552
19.7 Spot welded joints .................................... 555
19.8 Major topics of the present chapter ................... 556
References ................................................. 557
20 Designing against Fatigue of Structures .................... 559
20.1 Introduction .......................................... 559
20.2 Different types of structural fatigue problems ........ 560
20.3 Designing against fatigue ............................. 562
20.4 Uncertainties, scatter and safety margins ............. 566
20.4.1 Uncertainties .................................. 566
20.4.2 Scatter and safety factors ..................... 567
20.5 Some case histories ................................... 574
20.5.1 Improved shoulder fillets ...................... 575
20.5.2 Secondary bending introduced by non-symmetric
hole reinforcements ............................ 576
20.5.3 Cracked aircraft wing panel repaired with a
poorly designed patch .......................... 580
20.5.4 Online structural health monitoring of the
Tsing Ma Bridge ................................ 580
20.6 Summarizing conclusions ............................... 583
References ................................................. 585
Part VI Fatigue Resistance of Fiber-Metal Laminates
(Chapter 21)
21 Fatigue Resistance of Fiber-Metal Laminates ................ 589
21.1 Introduction .......................................... 589
21.2 Laminated sheet material without fibers ............... 591
21.3 Fiber-metal laminates Arall and Glare ................. 595
21.3.1 The fiber-metal laminate concept ............... 595
21.3.2 Fiber-metal laminates as sheet material ........ 597
21.3.3 Crack growth in Glare .......................... 600
21.3.4 Fatigue properties of Glare components ......... 603
21.4 More about Glare ...................................... 606
21.4.1 Some typical properties of Glare ............... 607
21.4.2 Production and design aspects of Glare
structures ..................................... 607
21.5 Some summarizing remarks .............................. 610
References ................................................. 611
Index ......................................................... 615
CD attached to this book
Contents:
I Exercises and Summaries
II Case Histories
III Special Topics
IV Research on Fatigue Problems in the Future
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