海洋结构物疲劳寿命预报的统一方法 英文版2025|PDF|Epub|mobi|kindle电子书版本百度云盘下载

海洋结构物疲劳寿命预报的统一方法 英文版PDF格式电子书版下载

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1 Introduction1

1.1 Fatigue Problems in Marine Structures1

1.2 Current Practices of Fatigue Strength Assessments and Their Deficiencies2

1.3 Historical Overview of Metal Fatigue3

1.4 FLP Methods6

1.4.1 CFD Theories6

1.4.2 FCP Theories17

1.5 The Layout of the Book22

References23

2 Current Understanding of Fatigue Mechanisms of Metals31

2.1 Introduction31

2.2 Difierent Phases of the Fatigue Life32

2.3 Crack Initiation Mechanisms for Different Metals34

2.3.1 Definition of a Crack Initiation34

2.3.2 Fatigue Crack Initiation in Slip Bands35

2.3.3 Crack Initiation Along the Grain Boundary(GB)36

2.3.4 Crack Initiation at Inclusions36

2.3.5 Slip Band and Dislocation in Single Crystal Metal39

2.3.6 Slip Band and Dislocation in Polycrystal Metal39

2.3.7 Fatigue Mechanism of Ultrafine-Grained Materials41

2.4 FCP Mechanisms42

2.4.1 Stage Ⅰ FCP43

2.4.2 Stage Ⅱ Crack Growth and Fatigue Striation44

2.5 Some Important Issues in Crack Growth47

2.5.1 Short Crack48

2.5.2 Crack Closure50

2.5.3 Effect of Loading Sequence52

2.5.4 Surface Effects54

2.5.5 Environmental Effects55

2.6 Fatigue Crack Growth Mechanism of Small Defects57

2.6.1 Engineering Initial Crack Size of Structures57

2.6.2 Definition of Short Crack and Long Crack58

2.6.3 Crack Growth Threshold and Intrinsic Crack Length59

2.6.4 Equivalent Crack Length for Short and Long Crack61

2.7 Summary62

References63

3 Current State-of-the-Art of UFLP69

3.1 Introduction69

3.2 Unified Approach for Three Regions of FCP69

3.3 Unified Approach to the Stress Ratio Effect or Mean Stress Effect70

3.4 Unified Approach for Long-and Physically Short-Crack Growth73

3.5 Unified Approach for Initiation and Propagation76

3.6 Unified Approach for High and Low Cycle Fatigue77

3.7 Unified Approach for Fatigue and Creep77

3.8 Basic Ideas of Our UFLP Method83

3.9 Summary84

References85

4 Basic Concepts of Fracture Mechanics91

4.1 Introduction91

4.2 Types of Cracks92

4.3 Types of Opening Modes for a Cracked Body94

4.4 SIFs95

4.4.1 Definition95

4.4.2 Calculation Methods of SIFs97

4.4.3 Typical Examples of SIFs98

4.4.4 Plasticity Limitations of the SIFs Based on LEFM99

4.4.5 Extensions of the SIFs Based on LEFM100

4.5 Fracture Toughness102

4.5.1 Definition102

4.5.2 Testing103

4.5.3 Trends104

4.6 Crack Tip Plasticity105

4.6.1 Plastic Zone for Plane Stress105

4.6.2 Plastic Zone for Plane Strain107

4.6.3 Plastic Zone Under Real Stress State108

4.7 Summary111

References112

5 Development of a UFLP Method for Marine Structures117

5.1 Introduction117

5.2 A General Procedure for the UFLP Method117

5.2.1 The General Function Format of the Fatigue Crack Growth Rate Curve for the UFLP Method117

5.2.2 Calculation of Fatigue Life118

5.3 Development of a Unified Fatigue Crack Growth Rate Model120

5.3.1 The Crack Growth Rate Model for Constant Amplitude Loading120

5.3.2 The Improved Crack Growth Rate Model Under VA Loading124

5.3.3 Establishment of Cycle-by-Cycle Integration Procedure128

5.3.4 Discussion of Model Parameters131

5.4 Engineering Approaches to Determine the Parameters in the Improved Model140

5.4.1 General Methods to Estimate the Model Parameters140

5.4.2 Estimation Method from Crack Growth Rate Data141

5.4.3 Estimation Method from a-N Curve141

5.4.4 Estimation Method from S-N Curve144

5.4.5 Estimation Method from ε-N Curve144

5.4.6 Estimation Methods from Available Static Test Properties147

5.4.7 Estimation of A and m149

5.5 Capabilities ofthe UFLP Method150

5.5.1 The Quantitative Analysis ofthe Improved Crack Growth Rate Model150

5.5.2 Model Validation by Test152

5.6 Summary167

References167

6 Description of Fatigue Loading173

6.1 The Nature of Fatigue Loading173

6.2 Load Spectra for CFD Analysis174

6.3 Generating the Whole Life Loading History from Short Time Measurement177

6.3.1 Method for Extrapolation of a Load History177

6.3.2 Choice of Threshold Levels181

6.3.3 Examples of Extrapolation of Load Histories182

6.4 Cycle Count Methods185

6.4.1 Definitions185

6.4.2 Rainflow Cycle Counting186

6.4.3 A Practical Example192

6.5 SLHs for FCP Analysis194

6.5.1 Definition194

6.5.2 History195

6.5.3 Basis of Generation of SLHs196

6.5.4 Generation of Load-Time Histories197

6.6 Generating a Pseudo Random Loading History from a Spectra203

6.7 Summary204

References205

7 Some Applications and Demonstrations of UFLP209

7.1 Introduction209

7.2 The Fatigue Crack Growth Rate of UFLP209

7.3 FLP of Specimen with Through-Thickness Crack Under Difierent Fatigue Loading210

7.3.1 FLP of D16 Aluminum Alloy Specimens Under Different Spectrum Loading210

7.3.2 FLP of Aluminum Alloy Al 7075-T6214

7.3.3 FLP of Specimen Made of 350WT Steel Under Different Overload Ratios218

7.3.4 The Fatigue Crack Growth Prediction of Steel HTS-A Under Multi-Level Block Loading219

7.4 FLP of Cracked Deck of an Oil Tanker224

7.4.1 Geometry of the Stifiened Plate225

7.4.2 The Crack Growth Pattern in the Stifiened Plate226

7.4.3 Determination of SIFs of the Cracked Stiffened Plate by FEA226

7.4.4 SIF of the Crack in Stiffened Plate by Weld Residual Stress230

7.4.5 Fatigue Crack Growth Prediction of the Stiffened Plate231

7.5 FLP of Submarine Hull Under Different Fatigue Loading Sequence233

7.5.1 General Equations for Calculating the SIF of a Surface Crack at Welded Toe233

7.5.2 SIF of Surface Crack Caused by Weld Residual Stress at Weld Toe235

7.5.3 Fatigue Crack Growth Prediction of Surface Crack at Weld Toe of Submarine Structure237

7.6 Summary241

References242

8 Code Development Based on UFLP for Marine Structures245

8.1 Introduction245

8.2 Procedure of UFLP246

8.3 Fatigue Loading248

8.3.1 Simplified Fatigue Loading Analysis249

8.3.2 Fatigue Loading by Direct Calculation251

8.4 SIF Calculation253

8.4.1 Planar Flaws and Their Initial Size255

8.4.2 SIF Range Calculation256

8.5 Fatigue Crack Growth Law of UFLP for Marine Structural Materials257

8.5.1 Recommended Fatigue Crack Growth Material Constants for Steels in Marine Environment258

8.5.2 Simplified Fatigue Crack Growth Law and Threshold(BS7910)263

8.6 Summary265

Appendix A：SIF Solutions for Some Typical Cracks265

References277

Index279