Machine Design: An Integrated Approach

Citation

Norton, R. L. (2019). Machine Design: An Integrated Approach (6th ed.). Pearson.

Chapter Summary

The sixth edition has 17 chapters in two parts, Part I: Fundamentals (Chapters 1–8) and Part II: Machine Design (Chapters 9–17), with four appendices: material properties, beam tables, stress-concentration factors and answers to selected problems. Pearson describes the book as aimed at junior- to senior-level mechanical engineering students, emphasising failure theory and analysis as well as the synthesis and design of machine elements.

Chapter 1: Introduction to Design

The design process and its stages (definition, preliminary design, detailed design, documentation), problem formulation, the engineering model with estimation, first-order analysis and the engineering sketch, and computer-aided design and engineering, including computational accuracy. It also covers the engineering report, factors of safety and design codes, statistical considerations and units.

Chapter 2: Materials and Processes

Material-property definitions (tensile, compression, bending, torsion and impact tests, fatigue strength, fracture toughness, creep), the statistical nature of properties, hardness and heat treatment, coatings and surface treatments. It surveys metals, polymers, ceramics and composites and ends with selecting materials.

Chapter 3: Kinematics and Load Determination

Degrees of freedom, mechanisms, common one-degree-of-freedom mechanisms (fourbar and sixbar linkages, cam and follower), and the position, velocity and acceleration analysis of the fourbar linkage and crank-slider. A section on cam design and analysis leads into load analysis: loading classes, free-body diagrams, static, dynamic and three-dimensional load cases with case studies, vibration and impact loading, and beam loading using singularity functions.

Chapter 4: Stress, Strain, and Deflection

Stress and strain, principal stresses, plane stress and plane strain, Mohr's circles, axial, shear and bearing stresses, bending, beam deflection (singularity functions, statically indeterminate beams, Castigliano's method), torsion, combined stresses and spring rates. The chapter also treats stress concentration, columns and thick- and thin-walled cylinders, and ends with case studies.

Chapters 5–6: Static Failure Theories; Fatigue Failure Theories

Chapter 5 covers failure of ductile materials (von Mises–Hencky, maximum shear stress, maximum normal stress), failure of brittle materials (Coulomb–Mohr, modified Mohr), fracture mechanics and the use of the theories, with case studies. Chapter 6 gives the mechanism of fatigue failure, stress-life, strain-life and fracture-mechanics models, fatigue loads, estimation of fatigue strength and correction factors, notches and residual stresses. It then designs for fully reversed, fluctuating and multiaxial stresses, with a general approach to high-cycle fatigue design and a case study.

Chapters 7–8: Surface Failure; Finite Element Analysis

Chapter 7 treats surface geometry, friction, adhesive, abrasive and corrosion wear, surface fatigue, and contact stresses for spherical, cylindrical and general contact, including dynamic contact. Chapter 8 introduces the finite element method: element types, meshing and convergence, boundary conditions, loads, verification of a model, and modal analysis.

Chapter 9: Design Case Studies

The first chapter of Part II introduces three design case studies: a portable air compressor, a hay-bale lifter and a cam-testing machine. They are labelled Case Studies 8, 9 and 10, and later chapters return to them as Case Studies 8B–8D, 9B and 10B–10C.

Chapters 10–11: Shafts, Keys, and Couplings; Bearings and Lubrication

Chapter 10 covers shaft loads, stresses and failure under combined loading, design for fully reversed or fluctuating loads, deflection, keys, splines, interference fits, flywheels, critical speeds, couplings, and a driveshaft case study. Chapter 11 covers lubricants and viscosity, hydrodynamic lubrication theory and bearing design, then rolling-element bearings, their failure and selection, and mounting.

Chapters 12–13: Spur Gears; Helical, Bevel, and Worm Gears

Chapter 12 includes gear tooth theory, interference, contact ratio, gear trains, manufacturing, loading, bending and surface stresses, materials and lubrication. Chapter 13 extends the treatment to helical gears, bevel gears and wormsets.

Chapters 14–17: Spring Design; Screws and Fasteners; Weldments; Clutches and Brakes

Chapter 14 treats helical compression, extension and torsion springs and Belleville washers. Chapter 15 covers thread forms, power screws, bolts and preloaded joints, joint stiffness, preload control and fasteners in shear. Chapter 16 covers welding processes, weld joints, static and dynamic loading of welds and eccentrically loaded weld patterns. Chapter 17 covers disk and drum clutches and brakes.

Key Concepts

Chapters 1–4: Design, Materials, Loads and Stress

• Engineering model and first-order analysis: estimating before computing in detail, with an engineering sketch.
• Mechanism and cam analysis: degree of freedom, the Grashof condition, vector-loop analysis of linkages and cam follower motion.
• Singularity functions: a method for beam loading and deflection used in Chapters 3 and 4.

Chapters 5–8: Failure, Surfaces and FEA

• Static failure theories: von Mises–Hencky, maximum shear stress, maximum normal stress, Coulomb–Mohr and modified Mohr.
• Stress-life, strain-life and LEFM approaches: three ways to model fatigue.
• Modified-Goodman diagram: a tool for design under fluctuating stresses.
• Contact stress: stress distributions and surface fatigue in spherical, cylindrical and general contact.

Chapters 9–17: Machine Elements and Case Studies

• Recurring case studies: the three designs of Chapter 9, developed in later chapters.
• Preloaded fasteners and joint stiffness: bolts in tension under static and dynamic loading.
• Gear stresses: bending and surface stresses in spur, helical, bevel and worm gearing.

Critical Analysis

Strengths

• Theory and design in one structure. Part I builds the analytical tools (loads, stress, static and fatigue failure, surface failure, finite elements) and Part II applies them to elements, which Pearson describes as an emphasis on failure theory together with synthesis and design.
• Case studies carried across chapters. The three case studies set out in Chapter 9 return in the shaft, bearing, gear, spring and fastener chapters, so one design is followed through several elements.
• Breadth of fundamentals. Kinematics, linkages and cams (Chapter 3), a full chapter on finite element analysis (Chapter 8) and extended fatigue coverage (stress-life, strain-life and LEFM approaches) are all in the contents. Pearson says the text is independent of any one computer program while emphasising computer-aided engineering.
• Specialised design topics. Chapters on weldments and on springs (including extension and torsion springs and Belleville washers) go into detail on allowable strengths and design procedures.

Limitations

• Gaps in the element coverage. The contents have no chapter on belts, chains or other flexible drives, and no separate chapter on rivets or adhesive bonding.
• A long Part I. Eight chapters, including kinematics and finite element analysis, come before the first element chapter, so the design of machine elements starts only at Chapter 10.
• Edition details are hard to pin down. Pearson lists the hardcover as a 2019 publication, a 2020 Mastering update and a 2021 e-text with a 2022 copyright, all under the sixth edition, so the year depends on the format.
• Case study numbering. The case studies are numbered from 8 in Chapter 9, and later chapters refer to them as 8B, 9B and so on, so a reader using a single chapter must go back to Chapter 9 to see which design a section extends.

Where It Fits in the Course

Norton's book overlaps most with Juvinall and Marshek's Fundamentals of Machine Component Design. Both give a long foundations section on loads, stress, failure and fatigue before turning to components. Norton adds kinematics, cams and a finite element chapter and carries three case studies through the element chapters, while Juvinall and Marshek treat belts and chains, rivets and bonding, micro- and nanoscale elements and a transmission case study. Either can be the main text; the other is a useful second explanation.

Mott's Machine Elements in Mechanical Design is described as a practical, step-by-step book on selecting and sizing elements, and Shigley's Mechanical Engineering Design as a core reference on designing components and checking them against expected loads at an upper level. Cross's Engineering Design Methods and Pahl and Beitz's Engineering Design: A Systematic Approach cover the design process and could be read before Norton's Chapter 1 or next to it.

How to Use This Book

Pearson aims the book at junior- to senior-level mechanical engineering students. Statics, dynamics and mechanics of materials are assumed, although Chapter 4 reviews stress, strain and deflection and Chapter 3 includes its own kinematics.

A practical plan:

• Core: Chapters 1, 4, 5 and 6. Fatigue (Chapter 6) recurs in the design of shafts, springs, fasteners and welds.
• Selective: Chapter 2 if materials knowledge is thin, Chapter 3 if the course has no separate kinematics, Chapter 7 for wear and contact stress, and Chapter 8 if finite element software is used in the course.
• Case studies: read Chapter 9 before the element chapters, then follow one case study through Chapters 10 to 15.
• Elements: Chapters 10–17 can be taken in the order a course needs; gears (12–13) and rolling bearings (11) are natural places to apply the contact-stress ideas of Chapter 7.

Work through the problems at the end of each chapter and check selected answers against Appendix D.