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Preface v

Acknowledgments ix

Symbols xix

Part 1 Fundamentals 1

1 Mechanical Engineering Design in Broad Perspective 1

1.1 An Overview of the Subject 1

1.2 Safety Considerations 2

1.3 Ecological Considerations 7

1.4 Societal Considerations 8

1.5 Overall Design Considerations 10

1.6 Systems of Units 12

1.7 Methodology for Solving Machine Component Problems 14

1.8 Work and Energy 16

1.9 Power 18

1.10 Conservation of Energy 19

2 Load Analysis 24

2.1 Introduction 24

2.2 Equilibrium Equations and Free-Body Diagrams 24

2.3 Beam Loading 34

2.4 Locating Critical Sections—Force Flow Concept 37

2.5 Load Division Between Redundant Supports 39

2.6 Force Flow Concept Applied to Redundant Ductile Structures 41

3 Materials 45

3.1 Introduction 45

3.2 The Static Tensile Test—“Engineering” Stress–Strain Relationships 46

3.3 Implications of the “Engineering” Stress–Strain Curve 47

3.4 The Static Tensile Test—“True” Stress–Strain Relationships 50

3.5 Energy-Absorbing Capacity 51

3.6 Estimating Strength Properties from Penetration Hardness Tests 52

3.7 Use of “Handbook” Data for Material Strength Properties 55

3.8 Machinability 56

3.9 Cast Iron 56

3.10 Steel 57

3.11 Nonferrous Alloys 59

3.12 Plastics and Composites 61

3.13 Materials Selection Charts 66

3.14 Engineering Material Selection Process 68

4 Static Body Stresses 77

4.1 Introduction 77

4.2 Axial Loading 77

4.3 Direct Shear Loading 79

4.4 Torsional Loading 80

4.5 Pure Bending Loading, Straight Beams 82

4.6 Pure Bending Loading, Curved Beams 83

4.7 Transverse Shear Loading in Beams 88

4.8 Induced Stresses, Mohr Circle Representation 94

4.9 Combined Stresses—Mohr Circle Representation 96

4.10 Stress Equations Related to Mohr’s Circle 99

4.11 Three-Dimensional Stresses 100

4.12 Stress Concentration Factors, K_t 104

4.13 Importance of Stress Concentration 107

4.14 Residual Stresses Caused by Yielding—Axial Loading 109

4.15 Residual Stresses Caused by Yielding—Bending and Torsional Loading 113

4.16 Thermal Stresses 115

4.17 Importance of Residual Stresses 117

5 Elastic Strain, Deflection, and Stability 119

5.1 Introduction 119

5.2 Strain Definition, Measurement, and Mohr Circle Representation 120

5.3 Analysis of Strain—Equiangular Rosettes 122

5.4 Analysis of Strain—Rectangular Rosettes 124

5.5 Elastic Stress–Strain Relationships and Three-Dimensional Mohr Circles 126

5.6 Deflection and Spring Rate—Simple Cases 128

5.7 Beam Deflection 130

5.8 Determining Elastic Deflections by Castigliano’s Method 133

5.9 Redundant Reactions by Castigliano’s Method 144

5.10 Euler Column Buckling—Elastic Instability 148

5.11 Equivalent Column Length for Various End Conditions 150

5.12 Column Design Equations—J. B. Johnson Parabola 151

5.13 Eccentric Column Loading—the Secant Formula 155

5.14 Equivalent Column Stresses 156

5.15 Other Types of Buckling 157

5.16 Finite Element Analysis 158

6 Failure Theories, Safety Factors, and Reliability 161

6.1 Introduction 161

6.2 Types of Failure 163

6.3 Fracture Mechanics—Basic Concepts 164

6.4 Fracture Mechanics—Applications 165

6.5 The “Theory” of Static Failure Theories 174

6.6 Maximum-Normal-Stress Theory 176

6.7 Maximum-Shear-Stress Theory 176

6.8 Maximum-Distortion-Energy Theory (Maximum-Octahedral-Shear-Stress Theory) 177

6.9 Mohr Theory and Modified Mohr Theory 179

6.10 Selection and Use of Failure Theories 180

6.11 Safety Factors—Concept and Definition 182

6.12 Safety Factors—Selection of a Numerical Value 184

6.13 Reliability 186

6.14 Normal Distributions 187

6.15 Interference Theory of Reliability Prediction 188

7 Impact 192

7.1 Introduction 192

7.2 Stress and Deflection Caused by Linear and Bending Impact 194

7.3 Stress and Deflection Caused by Torsional Impact 201

7.4 Effect of Stress Raisers on Impact Strength 204

8 Fatigue 210

8.1 Introduction 210

8.2 Basic Concepts 210

8.3 Standard Fatigue Strengths (S’_n) for Rotating Bending 212

8.4 Fatigue Strengths for Reversed Bending and Reversed Axial Loading 217

8.5 Fatigue Strength for Reversed Torsional Loading 218

8.6 Fatigue Strength for Reversed Biaxial Loading 219

8.7 Influence of Surface and Size on Fatigue Strength 220

8.8 Summary of Estimated Fatigue Strengths for Completely Reversed Loading 222

8.9 Effect of Mean Stress on Fatigue Strength 222

8.10 Effect of Stress Concentration with Completely Reversed Fatigue Loading 231

8.11 Effect of Stress Concentration with Mean Plus Alternating Loads 233

8.12 Fatigue Life Prediction with Randomly Varying Loads 240

8.13 Effect of Surface Treatments on the Fatigue Strength of a Part 243

8.14 Mechanical Surface Treatments—Shot Peening and Others 245

8.15 Thermal and Chemical Surface-Hardening Treatments (Induction Hardening, Carburizing, and Others) 246

8.16 Fatigue Crack Growth 246

8.17 General Approach for Fatigue Design 250

9 Surface Damage 255

9.1 Introduction 255

9.2 Corrosion: Fundamentals 255

9.3 Corrosion: Electrode and Electrolyte Heterogeneity 258

9.4 Design for Corrosion Control 259

9.5 Corrosion Plus Static Stress 262

9.6 Corrosion Plus Cyclic Stress 264

9.7 Cavitation Damage 264

9.8 Types of Wear 265

9.9 Adhesive Wear 265

9.10 Abrasive Wear 267

9.11 Fretting 268

9.12 Analytical Approach to Wear 269

9.13 Curved-Surface Contact Stresses 272

9.14 Surface Fatigue Failures 278

9.15 Closure 279

Part 2 Applications 282

10 Threaded Fasteners and Power Screws 282

10.1 Introduction 282

10.2 Thread Forms, Terminology, and Standards 282

10.3 Power Screws 286

10.4 Static Screw Stresses 295

10.5 Threaded Fastener Types 299

10.6 Fastener Materials and Methods of Manufacture 301

10.7 Bolt Tightening and Initial Tension 301

10.8 Thread Loosening and Thread Locking 305

10.9 Bolt Tension with External Joint-Separating Force 308

10.10 Bolt (or Screw) Selection for Static Loading 312

10.11 Bolt (or Screw) Selection for Fatigue Loading: Fundamentals 318

10.12 Bolt Selection for Fatigue Loading: Using Special Test Data 324

10.13 Increasing Bolted-Joint Fatigue Strength 327

11 Rivets, Welding, and Bonding 329

11.1 Introduction 329

11.2 Rivets 329

11.3 Welding Processes 330

11.4 Welded Joints Subjected to Static Axial and Direct Shear Loading 334

11.5 Welded Joints Subjected to Static Torsional and Bending Loading 337

11.6 Fatigue Considerations in Welded Joints 342

11.7 Brazing and Soldering 344

11.8 Adhesives 344

12 Springs 347

12.1 Introduction 347

12.2 Torsion Bar Springs 347

12.3 Coil Spring Stress and Deflection Equations 348

12.4 Stress and Strength Analysis for Helical Compression Springs—Static Loading 353

12.5 End Designs of Helical Compression Springs 355

12.6 Buckling Analysis of Helical Compression Springs 356

12.7 Design Procedure for Helical Compression Springs—Static Loading 357

12.8 Design of Helical Compression Springs for Fatigue Loading 360

12.9 Helical Extension Springs 368

12.10 Beam Springs (Including Leaf Springs) 369

12.11 Torsion Springs 374

12.12 Miscellaneous Springs 376

13 Lubrication and Sliding Bearings 379

13.1 Types of Lubricants 379

13.2 Types of Sliding Bearings 379

13.3 Types of Lubrication 380

13.4 Basic Concepts of Hydrodynamic Lubrication 381

13.5 Viscosity 383

13.6 Temperature and Pressure Effects on Viscosity 387

13.7 Petroff’s Equation for Bearing Friction 388

13.8 Hydrodynamic Lubrication Theory 390

13.9 Design Charts for Hydrodynamic Bearings 393

13.10 Lubricant Supply 399

13.11 Heat Dissipation and Equilibrium Oil Film Temperature 401

13.12 Bearing Materials 402

13.13 Hydrodynamic Bearing Design 404

13.14 Boundary and Mixed-Film Lubrication 409

13.15 Thrust Bearings 411

13.16 Elastohydrodynamic Lubrication 412

14 Rolling-Element Bearings 413

14.1 Comparison of Alternative Means for Supporting Rotating Shafts 413

14.2 History of Rolling-Element Bearings 415

14.3 Rolling-Element Bearing Types 415

14.4 Design of Rolling-Element Bearings 421

14.5 Fitting of Rolling-Element Bearings 424

14.6 “Catalog Information” for Rolling-Element Bearings 425

14.7 Bearing Selection 429

14.8 Mounting Bearings to Provide Properly for Thrust Load 436

15 Spur Gears 438

15.1 Introduction and History 438

15.2 Geometry and Nomenclature 439

15.3 Interference and Contact Ratio 447

15.4 Gear Force Analysis 450

15.5 Gear-Tooth Strength 453

15.6 Basic Analysis of Gear-Tooth-Bending Stress (Lewis Equation) 454

15.7 Refined Analysis of Gear-Tooth-Bending Strength: Basic Concepts 456

15.8 Refined Analysis of Gear-Tooth-Bending Strength: Recommended Procedure 458

15.9 Gear-Tooth Surface Durability—Basic Concepts 464

15.10 Gear-Tooth Surface Fatigue Analysis—Recommended Procedure 467

15.11 Spur Gear Design Procedures 471

15.12 Gear Materials 475

15.13 Gear Trains 476

16 Helical, Bevel, and Worm Gears 481

16.1 Introduction 481

16.2 Helical-Gear Geometry and Nomenclature 482

16.3 Helical-Gear Force Analysis 486

16.4 Helical Gear-Tooth-Bending and Surface Fatigue Strengths 489

16.5 Crossed Helical Gears 490

16.6 Bevel Gear Geometry and Nomenclature 491

16.7 Bevel Gear Force Analysis 493

16.8 Bevel Gear-Tooth-Bending and Surface Fatigue Strengths 494

16.9 Bevel Gear Trains; Differential Gears 497

16.10 Worm Gear Geometry and Nomenclature 498

16.11 Worm Gear Force and Efficiency Analysis 500

16.12 Worm-Gear-Bending and Surface Fatigue Strengths 505

16.13 Worm Gear Thermal Capacity 507

17 Shafts and Associated Parts 511

17.1 Introduction 511

17.2 Provision for Shaft Bearings 511

17.3 Mounting Parts onto Rotating Shafts 512

17.4 Rotating-Shaft Dynamics 515

17.5 Overall Shaft Design 519

17.6 Keys, Pins, and Splines 523

17.7 Couplings and Universal Joints 526

18 Clutches and Brakes 530

18.1 Introduction 530

18.2 Disk Clutches 530

18.3 Disk Brakes 535

18.4 Energy Absorption and Cooling 536

18.5 Cone Clutches and Brakes 537

18.6 Short-Shoe Drum Brakes 539

18.7 External Long-Shoe Drum Brakes 542

18.8 Internal Long-Shoe Drum Brakes 548

18.9 Band Brakes 550

18.10 Materials 553

19 Belts, Chains, and Other Components 555

19.1 Introduction 555

19.2 Flat Belts 555

19.3 V-Belts 557

19.4 Toothed Belts 561

19.5 Roller Chains 561

19.6 Inverted-Tooth Chains 563

19.7 History of Hydrodynamic Drives 565

19.8 Fluid Couplings 565

19.9 Hydrodynamic Torque Converters 568

20 Micro/Nanoscale Machine Elements 572

20.1 Introduction 572

20.2 Micro/Nanoscale Actuators 573

20.3 Micro/Nanoscale Bearings 579

20.4 Micro/Nanoscale Sensors 583

20.5 Conclusions 595

21 Machine Component Interrelationships—A Case Study 597

21.1 Introduction 597

21.2 Description of Original Hydra-Matic Transmission 597

21.3 Free-Body Diagram Determination of Gear Ratios and Component Loads 600

21.4 Gear Design Considerations 603

21.5 Brake and Clutch Design Considerations 605

21.6 Miscellaneous Design Considerations 606

22 Design and Fabrication of the Mechanical Systems for a Remote Control Car—A Design Project Case Study 609

22.1 Case Study Summary 609

22.2 Project Components 610

22.3 Project Organization 612

22.4 System Design Considerations 613

22.5 RC Car Race 617

Problems P-1

A Units A-1

A-1a Conversion Factors for British Gravitational, English, and SI Units A-1

A-1b Conversion Factor Equalities Listed by Physical Quantity A-2

A-2a Standard SI Prefixes A-4

A-2b SI Units and Symbols A-5

A-3 Suggested SI Prefixes for Stress Calculations A-6

A-4 Suggested SI Prefixes for Linear-Deflection Calculations A-6

A-5 Suggested SI Prefixes for Angular-Deflection Calculations A-6

B Properties of Sections and Solids A-7

B-1a Properties of Sections A-7

B-1b Dimensions and Properties of Steel Pipe and Tubing Sections A-8

B-2 Mass and Mass Moments of Inertia of Homogeneous Solids A-10

C Material Properties and Uses A-11

C-1 Physical Properties of Common Metals A-11

C-2 Tensile Properties of Some Metals A-12

C-3a Typical Mechanical Properties and Uses of Gray Cast Iron A-13

C-3b Mechanical Properties and Typical Uses of Malleable Cast Iron A-14

C-3c Average Mechanical Properties and Typical Uses of Ductile (Nodular) Iron A-15

C-4a Mechanical Properties of Selected Carbon and Alloy Steels A-16

C-4b Typical Uses of Plain Carbon Steels A-18

C-5a Properties of Some Water-Quenched and Tempered Steels A-19

C-5b Properties of Some Oil-Quenched and Tempered Carbon Steels A-20

C-5c Properties of Some Oil-Quenched and Tempered Alloy Steels A-21

C-6 Effect of Mass on Strength Properties of Steel A-22

C-7 Mechanical Properties of Some Carburizing Steels A-23

C-8 Mechanical Properties of Some Wrought Stainless Steels (Approximate Median Expectations) A-24

C-9 Mechanical Properties of Some Iron-Based Superalloys A-25

C-10 Mechanical Properties, Characteristics, and Typical Uses of Some Wrought Aluminum Alloys A-26

C-11 Tensile Properties, Characteristics, and Typical Uses of Some Cast-Aluminum Alloys A-27

C-12 Temper Designations for Aluminum and Magnesium Alloys A-28

C-13 Mechanical Properties of Some Copper Alloys A-29

C-14 Mechanical Properties of Some Magnesium Alloys A-30

C-15 Mechanical Properties of Some Nickel Alloys A-31

C-16 Mechanical Properties of Some Wrought-Titanium Alloys A-32

C-17 Mechanical Properties of Some Zinc Casting Alloys A-33

C-18a Representative Mechanical Properties of Some Common Plastics A-34

C-18b Properties of Some Common Glass-Reinforced and Unreinforced Thermoplastic Resins A-35

C-18c Typical Applications of Common Plastics A-36

C-19 Material Names and Applications A-37

C-20 Designer’s Subset of Engineering Materials A-40

C-21 Processing Methods Used Most Frequently with Different Materials A-41

C-22 Joinability of Materials A-42

C-23 Materials for Machine Components A-43

C-24 Relations Between Failure Modes and Material Properties A-45

D Shear, Moment, and Deflection Equations for Beams A-46

D-1 Cantilever Beams A-46

D-2 Simply Supported Beams A-47

D-3 Beams with Fixed Ends A-49

E Fits and Tolerances A-50

E-1 Fits and Tolerances for Holes and Shafts A-50

E-2 Standard Tolerances for Cylindrical Parts A-51

E-3 Tolerance Grades Produced from Machining Processes A-52

F MIL-HDBK-5J, Department of Defense Handbook: Metallic Materials and Elements for Aerospace Vehicle Structures A-53

F.1 Introduction A-53

F.2 Overview of Data in MIL-HDBK-5J A-53

F.3 Advanced Formulas and Concepts Used in MIL-HDBK-5J A-54

F.4 Mechanical and Physical Properties of 2024 Aluminum Alloy A-58

F.5 Fracture Toughness and Other Miscellaneous Properties A-64

F.6 Conclusion A-66

G Force Equilibrium: A Vectorial Approach A-68

G.1 Vectors: A Review A-68

G.2 Force and Moments Equilibrium A-69

H Normal Distributions A-71

H.1 Standard Normal Distribution Table A-71

H.2 Converting to Standard Normal Distribution A-73

H.3 Linear Combination of Normal Distributions A-73

I S–N Formula A-74

I.1 S–N Formula A-74

I.2 Illustrative Example A-75

J Gear Terminology and Contact-Ratio Analysis A-76

J.1 Nominal Spur-Gear Quantities A-76

J.2 Actual Quantities A-78

J.3 Illustrative Example A-79

Index I-1

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