7R25. Machine Design: A CAD Approach. - AD Dimarogonas (Deceased). Wiley, New York. 2001. 996 pp. ISBN 0-471-31528-1. $99.00.
Reviewed by G Lewis (Dept of Mech Eng, Univ of Memphis, 312 Eng Bldg, Memphis TN 38152).
In the discussion about pedagogical approaches in the field of mechanical engineering education, perhaps no issues are more contentious than those that deal with the definition of design, how to teach it, and methods to ensure its seamless integration into the curriculum. Thus, any new book on the subject of mechanical engineering design is awaited with bated breadth, to see the extent to which its contributions to the debate on the aforementioned issues and other pertinent matters are informative and/or innovative. It needs to be stated at the outset that this text does not disappoint. It takes a decidedly bold new approach to the subject, successfully synthesizing well-established principles with evolving concepts. In the end, the student (whom one suspects is the primary, if not the only, intended readership) is given a treat, spread over an Introduction section, 14 chapters, and close to a thousand pages. Taxonomically speaking, the material in this text may be divided into three groups: description of the historical evolution of machine design as a key engineering process; the principles of machine design; and the applications of these principles to specific cases.
In the Introduction section, The machine: a historical introduction, the author captures completely the spectrum of changes that occurred in the approaches to machine design over a period that spans several centuries, from the design of water storage systems in Potamic Civilizations through the design of the pendulum clock in the Middle Ages to the design of the first practical locomotive, by George Stephenson, in 1829. This chapter also contains discussions of the following two topics: the group technology concept, which had its genesis in the pioneering work on symbolic representation carried out in the 17th and 18th centuries; and the evolution of machine design methodology, from the first application of engineering science to mechanical design performed at the Ecole Polytechnique (during the early part of the 19th century) to the “comprehensive model” introduced by Pahl and Beitz in 1996.
Machine design principles are expounded upon in Chapters 1 to 7. In many parts of these chapters, the author breaks no new ground; rather, he offers succinct treatment of a wide menu of familiar topics. In other portions, though, the author is very informative on a number of less familiar topics.
The thrust of Chapter 1, Machine design methodology, is the illustration of the processes to be used in identifying the most promising design solution from a given or derived set of candidate concepts. The key topics covered in this chapter are: the relative attractions and drawbacks of the “traditional” or “sequential” machine design procedure proposed by George Sandor, in 1964, compared to the more modern concurrent design procedure; axiomatic foundation and design rules (Reuleaux’s design rule, Suh’s axioms, revised design rules); conventional, intuitive, and systematic methods of generating machine functional concepts; development of alternative design concepts and use of the morphological table; and myriad philosophical and legal aspects of machine design (aesthetics, product liability, “green” design, etc).
In Chapter 2, Kinematic analysis of machines, the reader is provided with a comprehensive treatment of the kinematics principles that are used to obtain the main dimensions of a machine. Among the topics covered are: fixed kinematic pairs, velocity and acceleration analyses of closed-loop and open-loop linkages, cams and followers, kinematics of gears, and geometry of spur gears.
In Chapter 3 (Analysis of machine loads), the principles to be used in determining the magnitude of the loads to which a machine member is subjected during service are presented. Energy, work, power flow analysis, force analysis in general determinate system, internal loading diagram, and deflection analysis are the concepts treated.
In Chapter 4 (Machine design materials and manufacture), various aspects of engineered materials are discussed. These include: effect of test temperature, test loading rate, and time on the tensile properties of materials; materials processing methods; materials selection; determination of factor of safety; and estimation of statistical parameters relevant to design reliability.
In Chapter 5 (Sizing machine components for strength), the basic mechanics of materials concepts are presented. The topics covered may be clustered into four groups. The first group is the analysis of stresses developed when a machine member is subjected to quasi-static tension force, compression force, torque, or bending moment acting alone. The second group focuses on stress analysis when the aforementioned types of loading act simultaneously on the member. The third group considers stress analysis of various common machine components (such as thin- and thick-walled pressure vessels, interference fit joints, and rotating disks). Stress analysis when a machine member is subjected to dynamic loading is covered in the fourth group.
The various methods that may be used to model all features of a machine’s components and track the machine’s overall performance are the subject of Chapter 6 (Computer methods for machine modeling). The salient features of two broad categories of these methods are presented. The first is geometric modeling (exemplified by computer-aided machine design). The examples discussed in second category of methods, solid modeling, are wireframe, surface, and constructive solid geometry modeling. Other topics covered in this chapter include: geometric transformation of data, mesh generation, the finite element stress analysis method, and stress analysis of axisymmetric solids.
The utilization of machine models to obtain final machine design and methods of obtaining the best possible performance of the selected design are covered in Chapter 7 (Machine design synthesis). The opening sections of the chapter deal with some fundamental concepts of machine design formalization (namely, machine synthesis, its application to kinematic synthesis of linkages, and uses of a machine macromodel). The rest of the chapter is devoted to a detailed treatment of the principles of machine design optimization, moving from development of the general optimization statement to primers on analytical, numerical, and search algorithmic methods for obtaining maxima or minima in an optimization problem, and concluding with a description of the concept of the minimization of the total cost function.
In the third group of chapters (comprising Chapters 8 to 14), all the concepts covered in the previous chapters are combined with relevant special considerations to present the details of methods that may be used to size a wide variety of common machine elements. These elements are: rivets, bolts, welded joints, and interference fits (Chapter 8); springs, machine mounts and foundations (Chapter 9); clutches, brakes, and friction belts (Chapter 10); hydrodynamic and hydrostatic bearings (Chapter 11); dry contacts and rolling bearings (Chapter 12); spur, helical, and bevel gears, crossed gearing, worm gear drives, and chain drives (Chapter 13); and shafts, couplings, and keys (Chapter 14). In each of these chapters, the presentational format has three commonalities. First, the underlying principles and governing equations are presented (for example, “stress distribution in highly loaded contacts” and “elastohydrodynamic lubrication” in Chapter 12). Second, the selection application(s) are described in detail (for example, in Chapter 12, classes of roller bearings, antifriction bearing design database, bearing loads, and load distribution within a bearing are among the topics covered). Third, example problems are solved. Fourth, an actual relevant case study is described (in Chapter 12, this involved the redesign, by Task Corporation, of the ball bearings of the electric motors for pumps in the hydraulic systems in the Thunder 99 aircraft).
This text has five key attractive features. First, the historical antecedents are given for each of the important principles described. (As a bonus, potted biographies and photographs of all the persons involved in the development of these principles are included.) This is a commendable contribution to the much-neglected field of the history of engineering (there are many of today’s young computer nerds who truly believe that Steve Jobs or Bill Gates introduced computing!). Second, many of the case studies presented, all of which are culled from actual events, highlight the way in which machine component design analysis may be utilized in the analysis of service failure of a component. Third, many worked examples are provided of the use of computer methods to solve machine design problems. Fourth, the text has very pleasing aesthetics: a plethora of appropriate typefaces; crisp and fully-annotated diagrams; and well laid-out tables. Fifth, the six appendices are a compendium of much needed information on stress concentration factors, dimensions of standard machine elements, geometrical characteristics of standard hot rolled section members, and properties of various alloys, and the properties of four common cross-sections.
There are two main shortcomings of this text. First, a number of important topics are not covered at all, three examples being: theories of failure for filamentary composite materials (such as the Tsai-Wu theory); the use of the Weibull distribution in analyzing machine component failure data; and cumulative fatigue failure methods, other than the Palmberg-Miner rule (an example is the Corten-Dolan rule). Second, the omission of a discussion of the principles and applications of the geometric element modeling method (upon which the widely-used, commercially-available software, ProEngineer®, is based) in this text, which has a publication date of 2001, is both surprising and disappointing.
All things considered, the author has written an impressive and highly-readable text, and the present reviewer thus recommends Machine Design: A CAD Approach very highly to both mechanical engineering students and designers, especially those in the early part of their careers.
