Mechanical engineering designPDF电子书下载

Part 1 Basics 1

1 Introduction 3

1-1 Design 5

1-2 Mechanical Engineering Design 7

1-3 Your Path to Competence 12

1-4 Technology Can Be Fragile 12

1-5 Interaction between Design Process Elements 14

1-6 Codes and Standards 17

1-7 Economics 18

1-8 Safety and Product Liability 20

1-9 The Adequacy Assessment 20

1-10 Uncertainty 22

1-11 Stress and Strength 26

1-12 Design Factors and Factors of Safety 29

1-13 Reliability 30

1-14 Numbers， Units， and Preferred Units 31

Problems 37

2 Addressing Uncertainty 47

2-1 Questions Come with the Territory 49

2-2 Estimating Statistical Parameters 50

2-3 Probability Density Function and Cumulative Distribution Function 53

2-4 Linear Regression 55

2-5 Propagation of Error 58

2-6 Simulation 61

2-7 Design Factor and Factor of Safety 63

2-8 Limits and Fits 68

2-9 Dimensions and Tolerances 71

2-10 Summary 77

Problems 79

3 Stress 93

3-1 Stress Components 94

3-2 Mohr Circles 96

3-3 Triaxial Stress 100

3-4 Uniformly Distributed Stress 102

3-5 Elastic Strain 103

3-6 Stress-Strain Relations 104

3-7 Equilibrium 104

3-8 Shear and Moment 106

3-9 Singularity Functions 108

3-10 Normal Stress in Flexure 111

3-11 Beams with Asymmetrical Sections 118

3-12 Shear Stresses in Beams 118

3-13 Shear Stresses in Rectangular-Section Beams 121

3-14 Torsion 123

3-15 Stress Concentration 129

3-16 Stresses in Cylinders 132

3-17 Rotating Rings 135

3-18 Press and Shrink Fits 135

3-19 Temperature Effects 137

3-20 Curved Members in Flexure 138

3-21 Contact Stress 144

3-22 Propagation of Error 149

3-23 Summary 154

Problems 154

4 Deflection and Stiffness 175

4-1 Spring Rates 176

4-2 Tension， Compression， and Torsion 177

4-3 Deflection Due to Bending 178

4-4 Finding Deflection by Integration 180

4-5 Finding Deflection by the Area-Moment Method 187

4-6 Finding Deflection by the Use of Singularity Functions 190

4-7 Strain Energy 193

4-8 Castigliano’s Theorem 195

4-9 Statistically Indeterminate Problems 198

4-10 Deflection of Curved Members 200

4-11 Compression Members—General 204

4-12 Long Columns with Central Loading 206

4-13 Intermediate-Length Columns with Central Loading 210

4-14 Columns with Eccentric Loading 210

4-15 Struts， or Short Compression Members 214

4-16 An Application： Round-Bar Clamps 216

4-17 Deflection of Energy-Dissipative Assemblies 220

4-18 Shock and Impact 229

4-19 Suddenly-Applied Loading 230

4-20 Propagation of Error 233

Problems 237

Part 2 Failure Prevention 253

5 Materials 255

5-1 Static Strength 256

5-2 Plastic Deformation 261

5-3 Strength and Cold Work 265

5-4 Hardness 268

5-5 Impact Properties 269

5-6 Temperature Effects 271

5-7 Numbering Systems 272

5-8 Sand Casting 274

5-9 Shell Molding 274

5-10 Investment Casting 275

5-11 Powder-Metallurgy Process 275

5-12 Hot-Working Processes 275

5-13 Cold-Working Processes 276

5-14 The Heat Treatment of Steel 277

5-15 Alloy Steels 279

5-16 Corrosion-Resistant Steels 280

5-17 Casting Materials 281

5-18 Nonferrous Metals 283

5-19 Plastics 285

5-20 Notch Sensitivity 287

5-21 Introduction to Fracture Mechanics 288

5-22 Stress-Corrosion Cracking 303

5-23 Quantitative Estimation of Properties of Cold-Worked Metals 303

5-24 Quantitative Estimation of Properties of Heat-Treated Steels 307

Problems 308

6 Failures Resulting from Static Loading 315

6-1 Static Strength 316

6-2 Stress Concentration 319

6-3 Hypotheses of Failure 322

6-4 Ductile Materials： Maximum-Shear-Stress （Tresca or Guest） Hypothesis 324

6-5 Ductile Materials：Strain-Energy Hypotheses 326

6-6 Ductile Materials：Internal-Friction Hypothesis 332

6-7 Criticism of Hypotheses by Data in Ductile Materials 334

6-8 Brittle Materials： Maximum-Normal-Stress （Rankine） Hypothesis 335

6-9 Brittle Materials： Modifications of the Mohr Hypothesis 337

6-10 The Criticism of Hypotheses by Data in Brittle Materials 341

6-11 What Our Failure Models Tell Us 342

6-12 Interference—General 343

6-13 Static or Quasi-Static Loading on a Shaft 347

Problems 352

7 Failure Resulting from Variable Loading 359

7-1 Introduction to Fatigue in Metals 360

7-2 Strain-Life Relationships 361

7-3 Stress-Life Relationships 367

7-4 The Endurance Limit 369

7-5 Fatigue Strength 372

7-6 Endurance-Limit Modifying Factors 374

7-7 Stress Concentration and Notch Sensitivity 383

7-8 Applying What We Have Learned about Endurance Limit and Endurance Strength 387

7-9 The Distributions 395

7-10 Characterizing Fluctuating Stresses 396

7-11 Failure Loci under Variable Stresses 398

7-12 Torsional Fatigue Strength under Pulsating Stresses 408

7-13 Combinations of Loading Modes 408

7-14 Stochastic Failure Loci under Fluctuating Stresses 411

7-15 Cumulative Fatigue Damage 414

7-16 The Fracture-Mechanics Approach 421

7-17 Surface Fatigue Strength 423

7-18 The Designer’s Fatigue Diagram 429

7-19 An Important Design Decision： The Design Factor in Fatigue 431

Problems 436

Summary of Parts 1 and 2 441

Part 3 Design of Mechanical Elements 443

8 Screws， Fasteners， and the Design of Nonpermanent Joints 445

8-1 Thread Standards and Definitions 446

8-2 The Mechanics of Power Screws 450

8-3 Threaded Fasteners 457

8-4 Joints—Fastener Stiffness 458

8-5 Joints—Member Stiffness 461

8-6 Bolt Strength 466

8-7 Tension Joints—The External Load 470

8-8 Relating Bolt Torque to Bolt Tension 471

8-9 Statistically Loaded Tension Joint—Preload 477

8-10 Gasketed Joints 483

8-11 Tension Joints—Dynamic Loading 484

8-12 Adequacy Assessment， Specification Set，Decision Set， and Design 492

8-13 Shear Joints 498

8-14 Setscrews 504

8-15 Pins and Keys 504

Problems 513

9 Welding， Brazing， Bonding，and the Design of Permanent Joints 527

9-1 Welding Symbols 528

9-2 Butt and Fillet Welds 530

9-3 Stresses in Welded Joints in Torsion 535

9-4 Stresses in Welded Joints in Bending 540

9-5 The Strength of Welded Joints 542

9-6 Specification Set， Adequacy Assessment，and Decision Set 544

9-7 Static Loading 549

9-8 Fatigue Loading 554

9-9 Resistance Welding 557

9-10 Bolted and Riveted Joints Loaded in Shear 558

9-11 Adhesive Bonding and Design Considerations 562

Problems 579

10 Mechanical Springs 589

10-1 Stresses in Helical Springs 590

10-2 The Curvature Effect 591

10-3 Deflection of Helical Springs 592

10-4 Extension Springs 592

10-5 Compression Springs 595

10-6 Stability 596

10-7 Spring Materials 598

10-8 Helical Compression Springs for Static Service 609

10-9 Critical Frequency of Helical Springs 620

10-10 Fatigue Loading 622

10-11 Helical Compression Springs for Dynamic Service 625

10-12 Design of a Helical Compression Spring for Dynamic Service 629

10-13 Design of Extension Springs 637

10-14 Designing Helical Coil Torsion Springs 664

10-15 Belleville Springs 678

10-16 Miscellaneous Springs 678

10-17 Summary 680

Problems 683

11 Rolling-Contact Bearings 689

11-1 Bearing Types 690

11-2 Bearing Life 693

11-3 Bearing Load-Life Trade-off at Constant Reliability 694

11-4 Bearing Survival： The Reliability-Life Trade-off 696

11-5 Load-Life-Reliability Trade-off 697

11-6 Combined Radial and Thrust Loading 699

11-7 Variable Loading 704

11-8 Selection of Ball and Cylindrical Roller Bearings 709

11-9 Selection of Tapered Roller Bearings 714

11-10 Adequacy Assessment for Selected Rolling-Contact Bearings 724

11-11 Lubrication 728

11-12 Mounting and Enclosure 729

Problems 732

12 Lubrication and Journal Bearings 739

12-1 Types of Lubrication 741

12-2 Viscosity 741

12-3 Petroff’s Equation 744

12-4 Stable Lubrication 750

12-5 Thick-Film Lubrication 751

12-6 Hydrodynamic Theory 752

12-7 Design Considerations 757

12-8 The Relations of the Variables 759

12-9 Steady-State Conditions in Self-Contained Bearings 722

12-10 Clearance 781

12-11 Pressure-Fed Bearings 792

12-12 Loads and Materials 803

12-13 Bearing Types 805

12-14 Thrust Bearings 806

12-15 Boundary-Lubricated Bearings 807

Problems 823

13 Gearing-General 831

13-1 Types of Gears 832

13-2 Nomenclature 833

13-3 Tooth Systems 835

13-4 Conjugate Action 837

13-5 Involute Properties 838

13-6 Fundamentals 839

13-7 Contact Ratio 844

13-8 Interference 845

13-9 The Forming of Gear Teeth 848

13-10 Straight Bevel Gears 850

13-11 Parallel Helical Gears 851

13-12 Worm Gears 855

13-13 Gear Trains 856

13-14 Force Analysis—Spur Gearing 860

13-15 Force Analysis—Bevel Gearing 863

13-16 Force Analysis—Helical Gearing 866

13-17 Force Analysis—Worm Gearing 869

13-18 Gear Ratios and Numbers of Teeth 874

13-19 Gear-Shaft Speeds and Bearings 878

Problems 883

14 Spur and Helical Gears 897

14-1 The Lewis Bending Equation 898

14-2 Surface Durability 907

14-3 AGMA Stress Equations 909

14-4 AGMA Strength Equations 910

14-5 Geometry Factors I and J （ZI and YI ） 915

14-6 Elastic Coefficient C p（Z E） 920

14-7 Dynamic Factor K ’V 920

14-8 Overload Factor K O 922

14-9 Surface Condition Factors Cf and Z R 922

14-10 Size Factor K s 923

14-11 Load-Distribution Factor K m or K H 923

14-12 Hardness-Ratio Factor C H 924

14-13 Load Cycles Factors YN and Z N 926

14-14 Reliability Factors KR and Y Z 927

14-15 Temperature Factors KT and Y θ 928

14-16 Rim-Thickness Factor KB 928

14-17 Safety Factors SF and SH 929

14-18 Analysis 929

14-19 An Adequacy Assessment of a Gear Mesh 940

14-20 Design of a Gear Mesh 942

Problems 947

15 Bevel and Worm Gears 951

15-1 Bevel Gearing—General 952

15-2 Bevel-Gear Stresses and Strengths 954

15-3 AGMA Equation Factors 957

15-4 Straight-Bevel Gear Analysis 969

15-5 Design of a Straight-Bevel Gear Mesh 972

15-6 Worm Gearing—AGMA Equation 974

15-7 Worm-Gear Analysis 978

15-8 Designing a Worm-Gear Mesh 980

15-9 Buckingham Wear Load 985

Problems 986

16 Clutches， Brakes， Couplings， and Flywheels 991

16-1 Rudiments of Brake Analysis 993

16-2 Internal Expanding Rim Clutches and Brakes 999

16-3 External Contracting Rim Clutches and Brakes 1008

16-4 Band-Type Clutches and Brakes 1011

16-5 Friction-Contact Axial Clutches 1013

16-6 Disk Brakes 1016

16-7 Cone Clutches and Brakes 1022

16-8 Self-Locking Tapers and Torque Capacity 1024

16-9 Energy Considerations 1026

16-10 Temperature Rise 1027

16-11 Friction Materials 1031

16-12 Miscellaneous Clutches and Couplings 1032

16-13 Flywheels 1034

16-14 Adequacy Assessment for Clutches and Brakes 1039

Problems 1040

17 Flexible Mechanical Elements 104917-1 Belts 1050

17-2 Flat- and Round-Belt Drives 1053

17-3 V Belts 1069

17-4 Timing Belts 1077

17-5 Roller Chain 1079

17-6 Wire Rope 1088

17-7 Flexible Shafts 1097

Problems 1098

18 Shafts and Axles 1107

18-1 Introduction 1108

18-2 Sufficing Geometric Constraints 1111

18-3 Sufficing Strength Constraints 1120

18-4 The Adequacy Assessment 1128

18-5 Shaft Materials 1134

18-6 Hollow Shafts 1135

18-7 Critical Speeds 1135

18-8 Shaft Design 1141

18-9 Computer Considerations 1142

Problems 1146

Appendixes 1153

A Statistical Relations 1153

B Linear Regression 1161

C Propagation of Error Relations 1163

D Simulation 1165

E Useful Tables 1169

F Solutions to Selected Problems 1231

Index 1237