Applied Creep Mechanics / Edition 1

by Wei Sun, Christopher J. Hyde, Thomas H. Hyde

Overview

Applied Creep Mechanics fully discusses the time-dependent deformation which occurs in a metal when subjected to stress at an elevated temperature. This book explains how to perform detailed analyses of welded components; assess the conditions under which cracks may initiate and grow; and extract valuable information about the current state of the material, which may have been in service for many years.

This practical guide provides tested techniques for improving the design and life assessment methods for high-temperature components in power plants, chemical plants, and aero engines. The information presented in this book will help you optimize maintenance and repair, save time, reduce costs, and improve operational efficiency.

• Provides real-world industrial perspective on how to apply techniques to practical problems
• Case studies with linear and non-linear material behavior models
• Solution methods based on equilibrium compatibility and stress-strain and energy concepts
• Discusses high-temperature creep of engineering components; high-temperature structural analysis; high-temperature fracture mechanics; and damage mechanics
• Covers welded, notched, and cracked components
• State-of-the-art coverage of thermo-mechanical fatigue (TMF)

Product Details

ISBN-13:	9780071828697
Publisher:	McGraw Hill LLC
Publication date:	10/18/2013
Pages:	384
Product dimensions:	6.30(w) x 9.10(h) x 1.00(d)

About the Author

Tom H. Hyde, Wei Sun, and Chris J. Hyde have been on the engineering faculty at the University of Nottingham for a combined period of 56 years. All three are highly active researchers and teachers in solid mechanics, with a strong emphasis on the high-temperature behavior of materials and components. The authors have published more than 400 papers and have successfully supervised more than 50 PhD students. They have taught modules to students at all levels in BSc, MSc, BEng, and MEng courses, as well as having taught industry-based courses. Funding for their research has been obtained from a wide range of governmental and industrial collaborators. Professor Tom Hyde was the founding director of the Rolls-Royce UTC (University Technology Centre) on aero-engine transmission systems, at the University of Nottingham. Wei Sun is an associate professor, and Chris Hyde is a lecturer.

Table of Contents

Preface xiii

1 Introduction 1

Notation 8

References 8

2 General Solid Mechanics Background 9

2.1 Material Behavior When Subjected to a Uniaxial State of Stress 9

2.1.1 Elastic Behavior of Materials 9

2.1.2 Elastic-Plastic Behavior of Materials 10

2.1.3 Creep Behavior of Materials 14

2.2 Material Behavior When Subjected to a Multiaxial State of Stress 18

2.2.1 Elastic Behavior of Materials 18

2.2.2 Elastic-Plastic Behavior of Materials 20

2.2.3 Creep Behavior of Materials 23

2.3 Structural Analysis of Linear-Elastic Components 27

2.3.1 Description of Broad Problem Types 27

2.3.2 Linear-Elastic Bending of Beams 30

2.3.3 Linear-Elastic Behavior of Internally Pressurized Thick Tubes 32

2.3.4 Application of an Energy-Based Method to Linear-Elastic Components 35

2.4 Elastic-Plastic Analysis of Components 39

2.4.1 Elastic-Plastic Bending of Beams 39

2.4.2 Elastic-Plastic Behavior of Internally Pressurized Tubes 40

2.4.3 Notch Stresses and Strains 41

2.5 Fatigue and Fracture Mechanics 43

2.5.1 Basic Phenomena 43

2.5.2 Fatigue Data 44

2.5.3 Effect of Mean Stress 45

2.5.4 Effect of Stress Concentrations 46

2.5.5 Linear-Elastic Fracture Mechanics 47

2.5.6 Fatigue Crack Growth! 52

2.6 The Finite Element Method 54

Notation 55

References 56

3 Material Behavior Models for Creep Analysis 59

3.1 Introduction 59

3.2 Norton's Creep Law for Secondary Creep 61

3.2.1 The Model 61

3.2.2 Estimating the Material Constants 61

3.3 Damage Mechanics Models 62

3.3.1 Single-Damage Parameter Equations 62

3.3.2 Two-Damage Parameter Equations 74

3.4 Unified Viscoplasticity Model 78

3.4.1 The Basic Model 78

3.4.2 Estimating the Material Constants for the Chaboche Unified Viscoplasticity Model 81

3.5 Optimization of Material Constants for the Viscoplasticity Model 95

3.5.1 Basis of the Optimization Process 95

3.5.2 The Optimization Procedure 98

3.6 Other Models 104

Notation 106

References 107

4 Stationary State Creep of Single-Material, Uncracked Components 111

4.1 General Behavior of Components Under Creep Conditions 111

4.2 Statistically Determinate Problems 115

4.2.1 Axially Loaded Tapered Bar 116

4.2.2 Axially Loaded Stepped Bar 117

4.2.3 Internally Pressurized Thin Cylinder with Closed Ends 118

4.2.4 Internally Pressurized Thin Sphere 120

4.3 Statistically determinate Problems 121

4.3.1 Beams Subjected to Pure Bending 121

4.3.2 Deflections of Beam-Type Structures 123

4.3.3 Pure Torsion of a Circular Bar 131

4.3.4 Internally Pressurized Thick Cylinder 132

4.3.5 Internally Pressurized Thick Sphere 138

4.3.6 Two-Bar Structure 143

Notation 144

Reference 145

5 Inferences from Single-Material, Uncracked, Stationary-State Creep Analyses 147

5.1 Stationary-State Deformation Rates 147

5.2 Stationary-State Stress Distributions 155

5.3 Maximum Stationary-State Stresses 159

Notation 163

References 164

6 Stationary-State Creep of Multimaterial Uncracked Components 165

6.1 Multibar Structures 170

6.1.1 Two-Bar Structure 170

6.1.2 Three-Bar Structure 172

6.2 Multimaterial "Sandwich" Beam Components 173

6.2.1 Two-Material "Sandwich" Beam Components 173

6.2.2 Three-Material "Sandwich" Beam Components 177

6.3 Multimaterial Compound Internally Pressurized Thin Spheres 181

6.3.1 Two-Material Compound Spheres 181

6.3.2 Three-Material Compound Spheres 183

6.4 Multimaterial Compound Internally Pressurized Thin Tubes 184

6.4.1 Two-Material Compound Cylinders 184

6.4.2 Three-Material Compound Cylinders 187

6.5 Multimaterial Compound Internally Pressurized Thick Cylinders 189

6.5.1 Two-Material Thick Cylinders 189

6.5.2 Three-Material Thick Cylinders 191

6.6 General Form of the Solutions for Stresses in Multimaterial Components 193

6.7 General Form of the Solutions for Deformation in Multimaterial Components 198

Notation 199

References 200

7 Applications of the Finite Element Method for Single-Material Components 201

7.1 Introduction 201

7.2 The Example Geometries and Loading Modes 202

7.3 Finite Element Meshes and Boundary Conditions 205

7.4 Material Behavior Models 207

7.4.1 Initial Linear-Elastic Properties 207

7.4.2 Norton Power-Law Properties 207

7.4.3 Continuum-Damage Material Properties 208

7.5 Linear-Elastic Behavior 208

7.5.1 Notched Bar 208

7.5.2 Internally Pressurized Thick Pipe 208

7.5.3 Internally Pressurized Pipe Bend 208

7.6 Stationary-State Creep Behavior 210

7.6.1 Notched Bar 210

7.6.2 Internally Pressurized Thick Pipes 213

7.6.3 Internally Pressurized Pipe Bend 214

7.7 Continuum Damage Behavior 215

7.7.1 Notched Bar 215

7.7.2 Internally Pressurized Thick Pipe 215

7.7.3 Internally Pressurized Toroid 216

7.8 General Observation of Component Behavior 218

Notations 219

References 219

8 Creep of Welded Components 221

8.1 Introduction 221

8.2 The Creep of Longitudinal and Transverse Uniaxial Specimens 226

8.2.1 Columnar and Equiaxed Compositions 226

8.2.2 Typical Experimental Behavior 226

8.2.3 Finite Element Modeling of Weld Metal 227

8.3 Creep of Cross-Weld Specimens 237

8.3.1 Geometry and Loading 237

8.3.2 Stationary-State Creep of Two-Material Cross-Weld Specimens with Norton Creep Models 238

8.3.3 Stress Singularity in Cross-Weld Creep Test Specimens under Steady-State Conditions 245

8.3.4 The Effect of Including Damage on the Predicted Behavior of Cross-Weld Test Specimens 252

8.4 Creep of Circumferentially Welded Straight Pipes 258

8.4.1 Geometry and Loading 258

8.4.2 Stationary-State Creep of Circumferentially Welded Straight Pipes 260

8.4.3 The Effect of Including Damage on the Predicted Behavior of Circumferentially Welded Straight Pipes 269

Notation 280

References 281

9 Creep of Notched Components 285

9.1 Introduction 285

9.2 Elastic-Creep Behavior 285

9.3 Elastic-Plastic Creep Behavior 288

9.4 Comparison of the Techniques for Predicting Notch Stresses and Strains 290

9.5 Use of the Neuber Method in Conjunction with a Time-Stepping Integration Method 291

9.6 Determination of Principal Stresses and Strains 295

Notation 298

References 299

10 Creep of Cracked Components 301

10.1 Introduction 301

10.2 The Creep Fracture Mechanics Approach 303

10.2.1 Stationary Cracks 303

10.2.2 Growing Crack 307

10.2.3 Crack Growth Predictions Using the C* Parameter 308

10.3 The Damage-Mechanics Approach 311

10.3.1 The General Approach 311

10.3.2 Determination of the Multiaxial Stress-State Parameter α That Is Suitable for Crack Growth Predictions 313

10.3.3 Prediction of Crack Front Shape for CT Specimens 317

10.3.4 Prediction of Crack Growth and Crack Shape for a Rectangular Bar with a Thumbnail Crack 317

Notation 324

References 324

11 Small Specimen Creep Testing 327

11.1 Introduction 327

11.2 Subsize Conventional Specimens and Creep Testing 329

11.3 Impression Creep Test Specimens and Testing 330

11.3.1 Background 330

11.3.2 Interpretation of Impression Creep Test Data 331

11.3.3 Inverse Reference Stress Method 332

11.3.4 Use of a Rectangular Indenter 332

11.3.5 Typical Results and Practical Limitations 334

11.4 Small Punch Test Specimens and Testing 340

11.4.1 Background 340

11.4.2 Interpretation of Small Punch Creep Test Data 342

11.4.3 Typical Results and Practical Limitations 344

11.5 Small Ring-Type Test Specimens and Testing 344

11.5.1 Background 344

11.5.2 Typical Results and Practical Limitations 346

11.6 Two-Bar Test Specimens and Testing 349

11.6.1 Background 349

11.6.2 Interpretation of Two-Bar Creep Test Data 349

11.6.3 Typical Results and Practical Limitations 350

11.7 General Observations 352

Notation 353

References 353

Index 357