Design of Mechanical Elements: A Concise Introduction to Mechanical Design Considerations and Calculations

ISBN-13: 9781119849919 / Angielski / Twarda / 2022 / 256 str.

Bart Raeymaekers

Spis treści

About the author xiPreface xiiiAbout the Companion Site xv1 Mechanical Design 11.1 Introduction 11.2 Mechanical Design Process 11.3 Mechanical Elements 41.4 Standards and Codes 41.5 Uncertainty in Mechanical Design 51.6 Design for Safety 91.7 Key Takeaways 91.8 Problems 102 Material Selection 132.1 Introduction 132.2 Material Classification 132.3 Mechanical Properties 142.3.1 Strength and Stiffness 142.3.2 Elastic Versus Plastic Strain 162.3.3 Resilience 172.3.4 Toughness 182.3.5 Engineering Stress-Strain Diagram Summary 192.3.6 True Stress-Strain Diagram 192.4 Materials Processing 202.4.1 Hot Versus Cold Processing 202.4.2 HotWorking 212.4.3 ColdWorking 212.4.3.1 Process 212.4.3.2 Reduction in Area 222.4.3.3 ColdWork Factor 232.4.3.4 Modifying Material Properties Using ColdWork 232.5 Alloys 262.5.1 Numbering Systems 262.5.2 Plain Carbon Steels 272.5.3 Alloy Steels 282.6 Key Takeaways 282.7 Problems 293 Statistical Considerations 333.1 Introduction 333.2 Random Variables and Distributions 333.3 Density Functions 343.3.1 Probability Density Function 343.3.2 Cumulative Density Function 343.4 Metrics to Describe a Distribution 353.5 Linear Combination of Random Variables 373.6 Types of Distributions 393.6.1 Uniform Distribution 393.6.2 Normal Distribution 413.6.3 Weibull Distribution 453.7 Key Takeaways 483.8 Problems 484 Tolerances 534.1 Introduction 534.2 Terminology 534.3 Preferred Fits and Tolerances 554.3.1 ISO 286 Method 554.3.2 Unit Shaft and Unit Hole System 594.4 Tolerance Stacks 604.5 Key Takeaways 634.6 Problems 645 Design for Static Strength 695.1 Introduction 695.2 Simple Loading 705.2.1 Axial Loading 705.2.2 Bending 715.2.3 Torsion 725.3 Stress Concentrations 735.4 Failure Criteria 795.4.1 Failure Criteria for Ductile Materials 795.4.1.1 Maximum Normal Stress Theory (Rankine) 795.4.1.2 Maximum Shear Stress Theory (Tresca) 795.4.1.3 Distortion Energy Theory (Von Mises) 805.4.1.4 Comparison Between Different Failure Criteria 815.4.2 Failure Criteria for Brittle Materials 825.4.2.1 Maximum Normal Stress Theory (Rankine) 825.4.2.2 Coulomb-Mohr Theory 835.4.2.3 Comparison Between Different Failure Criteria 835.5 Key Takeaways 855.6 Problems 856 Design for Fatigue Strength 916.1 Introduction 916.1.1 Types of Dynamic Loads 916.1.2 Fatigue Failure Mechanism 926.2 Fatigue-life Methods 936.3 Fatigue Strength 956.4 Endurance-limit Modifying Factors 966.4.1 ka: Surface Factor 976.4.2 kb: Size Factor 976.4.3 kc: Load Factor 986.4.4 kd: Temperature Factor 996.4.5 ke: Reliability Factor 996.4.6 kf : Miscellaneous Effects Factor 1006.5 Fluctuating Stresses 1016.6 Stress Concentrations 1056.7 Key Takeaways 1066.8 Problems 1067 Shafts 1117.1 Introduction 1117.1.1 Practical Considerations Related to Shaft Design 1117.1.2 Torque Transmission 1127.1.2.1 Relationship Between Torque, Power, and RPM 1127.1.2.2 Belt-Pulley Torque Transmission 1137.2 Recipe for Shaft Calculations 1137.2.1 Design Calculation 1147.2.2 Verification Calculation 1147.3 Example Calculations 1157.4 Critical Rotation Frequency of a Shaft 1227.5 Key Takeaways 1267.6 Problems 1268 Bolted Joints 1318.1 Introduction 1318.2 Power Screws 1318.2.1 Screw Thread Nomenclature and Geometry 1318.2.2 Power Screw Torque 1328.2.3 Self-locking 1358.2.4 Efficiency of a Power Screw 1358.2.5 Collar Friction 1368.3 Fasteners 1398.3.1 Screw Thread Nomenclature and Geometry 1398.3.2 Fastener Strength Category 1418.3.3 Bolt Preload 1418.3.4 Hexagonal Nuts 1428.3.5 Washers 1428.3.6 Torque Requirement 1428.3.7 Bolted Joints in Tension (Static) 1438.3.7.1 Determining the Preload Fi 1458.3.7.2 Stiffness of the Bolt 1468.3.7.3 Stiffness of the Members 1488.3.7.4 Stiffness of Members with a Gasket 1498.3.8 Bolted Joints in Tension (Dynamic) 1548.3.9 Bolted Joints in Shear 1578.4 Key Takeaways 1598.5 Problems 1609 Welded Joints 1659.1 Introduction 1659.1.1 Welding Versus Brazing 1659.1.2 Techniques and Materials 1659.2 Welded Joint Geometry 1689.3 Calculation ofWelded Joints 1699.3.1 Butt Welded Joints 1709.3.2 Simple Loading of Unidirectional FilletWelded Joints 1709.3.2.1 Case 1: Axial Load 1709.3.2.2 Case 2: Longitudinal Load 1729.3.2.3 Case 3: Transverse Load 1739.3.2.4 Case 4: In-plane Bending Moment 1759.3.2.5 Case 5: Out-of-plane Bending Moment 1779.3.2.6 Case 6: Torque Moment 1789.3.3 Combined Loading of Unidirectional FilletWelded Joints 1809.3.4 Multidirectional FilletWelded Joints 1829.3.4.1 Multidirectional FilletWelded Joints with In-plane Load, No Bending 1829.3.4.2 Multidirectional FilletWelded Joints with In-plane Load and Bending 1829.3.4.3 Multidirectional FilletWelded Joints with Torque Moment 1839.4 Key Takeaways 1879.5 Problems 18710 Rolling Element Bearings 19110.1 Introduction 19110.1.1 Definition 19110.1.2 Terminology and Geometry 19110.1.3 Design Parameters 19110.2 Types of Rolling Element Bearings 19210.3 Hertz Contact Stress 19310.3.1 Hertz Contact Stress Between Spherical Bodies 19510.3.2 Hertz Contact Stress Between Cylindrical Bodies 19610.4 Bearing Calculations 19810.4.1 Bearing Life 19810.4.2 Bearing Load 19810.4.3 Bearing Reliability 20010.4.4 Combined Radial and Axial Loading 20310.5 Key Takeaways 20510.6 Problems 20511 Gears 20911.1 Introduction 20911.1.1 Types of Gears 20911.1.2 Terminology 21111.2 Conjugate Gear Tooth Action 21311.3 Kinematics 21411.3.1 Involute 21411.3.2 Contact Ratio 21611.3.3 Gear Tooth System 21711.3.4 Interference 21711.4 Gear Force Analysis 21911.5 Gear Manufacturing 22211.5.1 Forming 22211.5.2 Machining 22211.6 Key Takeaways 22311.7 Problems 223A Area Moment of Inertia 225A.1 Introduction 225A.2 Terminology 225A.3 Parallel Axis Theorem 226A.4 Rotation About the Origin 227B Internal Force Diagrams 231B.1 Cantilever Beam with End Load 231B.2 Cantilever Beam with Intermediate Load 231B.3 Simple Supported Beam with Center Load 232B.4 Simple Supported Beam with Intermediate Load 233C Elementary Stress Element 235C.1 Introduction 235C.2 Principal Stresses 235C.3 Maximum Shear Stress 235Index 237

O autorze

Bart Raeymaekers is a Professor in the Department of Mechanical Engineering at the University of Utah, USA. His research focuses on tribology and engineered materials manufacturing and he teaches courses in mechanical design. He is an ASME Fellow and has been a multi-year recipient of the University of Utah, Department of Mechanical Engineering, Outstanding Teaching Award.