When we started on the first edition of this book in the late 1990s, we could not have predicted that we would someday be asked to prepare a fourth edition of a text for a then-controversial course. At that time, a cornerstone introduction to engineering design was indeed considered improbable, if not impossible or meaningless. Now such courses are a staple of many engineering programs, and we are proud to have helped bring that curricular adaptation to life. We have also been part of a similar adaptation of engineering's capstone courses, which were then often undertaken more in response to accreditation needs than a desire for real-world projects. Today externally focused capstone courses, some modeled on Harvey Mudd College's Engineering Clinic, not only give students an authentic design experience, but also often introduce them to working with peers scattered around the world. The students in the classroom or design studio have also changed: Many more women and underrepresented minority students now major in engineering.

These transitions have been accompanied by an evolution in the discipline of design and in the perception of engineering design by the faculties of engineering schools. In particular, design is now a recognized intellectual discipline, with a vocabulary, structure, and methods that reflect our increasing ability to articulate what we are doing when we design something. And as with many other disciplines, design ranges from the narrow and mathematical (e.g., kinematics, optimization) to the broad and transdisciplinary (e.g., the life of a product from its inception to use to disposal, the communication and teamwork skills that are the “soft” skills of engineering design).

We have also changed, certainly getting older, perhaps also becoming wiser. We have had opportunities to see how the design ideas we taught worked, which needed refinement, and which didn't work at all. We have tried to adapt this fourth edition both to the changing circumstances and to our increased knowledge of the world, the engineering profession, and our educational mission.

Of course, some things have not changed at all. Engineering design has always required attention to the wishes of the client, users, and the larger public. It is still true that engineers must organize their design processes to communicate their design thinking to their design partners. And it also remains true that effective design teams are those whose members respect one another. Perhaps most of all, a commitment to ethical design by and on behalf of a diverse community must remain at the forefront of what it is we do as engineers.

Today there are many more books on design, engineering design, project management, team dynamics, project-based learning, and the other topics we cover in this volume, than when we wrote our first edition. We wanted then—as we still do today—to combine these topics in a single, introductory work that focused particularly on conceptual design. That original desire arose from our teaching at Harvey Mudd College, where our students do team-based design projects in a first-year design course, E4: Introduction to Engineering Design (called “E4”), and in the Engineering Clinic. Clinic is an unusual capstone course taken by juniors (for one semester) and seniors (for both semesters) in which students work on externally sponsored design and development projects. In both E4 and Clinic, Mudd students work in multidisciplinary teams, under specified time deadlines, and within specified budget constraints. These conditions are meant to replicate to a significant degree the environments within which most practicing engineers will do much of their professional design work. In looking for books that could serve our audience, we found that there were excellent texts covering detailed design, usually targeted toward senior capstone design courses, or “introductions to engineering” that focused on describing the branches of engineering. We could not find a book that introduced the processes and tools of conceptual design in a project or team setting that we found suitable for first- and second-year students. And while other more “skills-oriented” texts and series have come onto the market since, we are gratified that a growing market has emerged for the book that addresses our original concerns.

In designing all four editions of this book, we confronted many of the same issues that we discuss in the pages that follow. It was important for us to be very clear about our overall objectives, which we outline below, and about the particular objectives we had for each chapter. We asked about the pedagogic function served by the various examples, and whether some other example or tool might provide a better means for achieving that pedagogical function. The resulting organization and writing represent our implementation of our best design. Thus, this and all books are designed artifacts: They require the same concern with objectives, choices, constraints, functions, means, budget, and schedule, as do other engineering or design projects.

This book is directed to three audiences: students, teachers, and practitioners. The book is intended to support students to learn about design, the central activity of engineering, by doing design. We view our design course, E4, as a setting in which students acquire design skills as they experience the activity of design by working on design projects. The book is intended to help students learn formal design tools and techniques as they solve conceptual design problems. They can then apply these formal methods to other design projects they will face later in their education in Clinic-like capstone courses and later in their careers. Students will also learn about communication, team dynamics, and project management. We have included examples of work done by our students on actual projects in E4, both to show how the tools are used and to highlight some frequently made mistakes.

We wrote this book with teachers also very much in mind. We thought about how to deliver the material to students, and about how introductory design courses could be taught. In this fourth edition, we decomposed and modularized much of the text, in order to avoid the confusion that often results when a new vocabulary is being learned; that is, to separate objectives from constraints, objectives from functions, functions from means, and customer requirements from design specifications. The modularization also provides options for instructors to structure their classes in a variety of ways, bringing forward (or deferring) discussions of communication, team dynamics, leadership, or management, because the chapters on these (and other) topics are self-contained. We also provide a complete design case study and two continuing design examples that can be used by an instructor as ongoing examples for illustration and as in-class exercises. (We don't assign homework problems in E4 as our students are working on their various E4 projects as “homework” when they're not in class.) In an accompanying Instructor's Manual, we outline sample syllabi and organizations for teaching the material in the book, as well as additional examples.

Finally, we hope the book will be useful to practitioners, either as a refresher of things learned or as an introduction to some essential elements of conceptual design that were not formally introduced in engineering curricula in years past. We do not assume that the case study or the illustrative design examples given here substitute for an engineer's experience, but we do believe that they show the relevance of these tools to practical engineering settings. Some of our friends and colleagues in the profession like to point out that the tools we teach would be unnecessary if only we all had more common sense. Notwithstanding that, the number and scale of failed projects suggest that common sense may not, after all, be so commonly distributed. In any case, this book offers both practicing engineers (and engineering managers) a view of the design tools that even the greenest of engineers will have in their toolbox in the coming years.

SOME REMARKS ON VOCABULARY AND WORD USAGE

There is no engineering design community that transcends all engineering disciplines or all types of engineering practice. For that very reason, words are used differently in different domains, and so differing technical jargons have developed. Since we want to provide a unified coherent understanding that would be a useful foundation for all of our students' future design work, whether in their formal studies or in their chosen careers, we begin our discussions of the major concepts and terms of art with formal dictionary definitions, but leavened by our understanding of today's “best practices” in design. We do this to remind readers that word usage has its roots in a shared understanding of vocabulary, in our case the English vocabulary. Even technical jargon has—or should have—a traceable path back to common usage. Thus, in this fourth edition we have worked much harder than we have before to be as crisp and consistent as possible with the words we chose to use.

Further, it is clear that words are used differently in the different domains of engineering practice. For example, different authors (in both the research literature and textbooks) define phases of the design process differently, with varying activities occurring within them. We have worked very hard to clearly articulate our model of the design process in Chapter 2. As we reviewed materials for this edition, we saw that the use of the terms requirements and specifications in engineering practice is not uniform. Thus, we choose to speak in terms of customer requirements to specify what the client wants and needs from her design (i.e., the client's objectives and constraints and the functions as she'd like them to happen), and design specifications to articulate in engineering terms how a design is supposed to perform its functions and, as appropriate, display its behaviors.

SOME SPECIFICS ABOUT WHAT'S COVERED

Design is an open-ended and ill-structured process, by which we mean there is no unique solution, and that the candidate solutions cannot be generated with an algorithm. As we emphasize in the early chapters, designers have to provide an orderly process for organizing an ill-structured design activity in order to support making decisions and trade-offs among possibly competing solutions. In such cases, algorithms and mathematical formulations cannot replace the imperative to understand the often subjective needs of various stakeholders (clients, users, the public, and so on)—even if those mathematical tools are used later in the design process. Perhaps ironically, this lack of structure and the inapplicability of formal mathematical tools make the introduction of conceptual design early in the curriculum possible and, we think, desirable. It provides a framework in which engineering science and analysis can be used, while not demanding skills that most first- and second-year students have not yet acquired. We have, therefore, included in this book the following specific tools for conceptual design, for acquiring and organizing design knowledge, and for managing the team environment in which design takes place.

The following formal conceptual design methods are delineated:

• objectives trees
• establishment of metrics to measure the achievement of objectives
• pairwise comparison charts (PCCs) to rank objectives
• functional analysis (including black and glass boxes, enumeration, function-means trees, and so on)
• morphological (“morph”) charts to develop design alternatives
• specifications development

Since both the framing or defining of a design problem and conceptual design thinking require and produce a lot of information, we introduce a variety of means to acquire and process information, including literature reviews, brainstorming, analogies, user surveys and questionnaires, reverse engineering (or dissection), simulation and computer analysis, and formal design reviews.

The successful completion of any design project by a team requires that team members estimate a project's scope of work, schedule, and resources early in the life of the project. To this end, we introduce several design management tools:

• work breakdown structures (WBSs)
• schedules
• budgets

We also discuss several other topics that we feel are increasingly important in a first exposure to design. We discuss the completion of a design project, with a strong emphasis on the ways and means of reporting design results in Chapters 9 and 10. These chapters allow instructors to focus on engineering communication as an integral part of the design process, including engineering drawings, reports, and presentations. We also present some more practical aspects of drawing and tolerancing in Appendix A. We did this because we wanted to bring together the basic skills needed in design, such as communicating through drawings by adhering to appropriate standards and conventions (e.g., geometric dimensioning and tolerances).

We also include a discussion about building physical models and prototypes in Chapter 11. We did this because we have also observed in our own students that most don't start college with much hands-on experience, even in basic woodcraft. Since we expect them to build elementary (physical) models and prototypes, it seemed only fair to include some understanding of what models and prototypes are, as well as (in Appendix B) some cautionary tips about working in a shop or laboratory, and some very basic tips on how to actually make (and fasten) some basic wooden parts.

In Chapter 12, we introduce some ideas about mathematical modeling in design, placed in the context of doing preliminary and detailed design. The material introduces principles of mathematical modeling to reinforce concepts behind applying mathematics and physics to engineering. Then we go on to illustrate a few of the kinds of calculations that might be done in the later phases of design. We illustrate the modeling of both battery-powered payload carts and a basic rung or step for a ladder, where we apply some results from elementary beam theory. Needless to say, in one chapter and in the kinds of course that we aimed this book toward, we could not delve into preliminary and detailed design in all engineering disciplines. What we present is representative of the “good habits of thought” needed to model and analyze designs in all disciplines.

In Chapter 13 we present a brief introduction to engineering economics and to the time value of money, the latter being quite important because we often need to balance initial or present costs against costs due, for example, to use, wear, and maintenance. In Chapter 14 we discuss “design for X” issues, including use, manufacturing and assembly, reliability and maintainability, and sustainability. This chapter provides a vehicle for faculty who want to expand on these topics and lead students into issues such as concurrent design, DFM, or emerging areas such as sustainability and carbon footprints.

In Chapter 15 we undertake a discussion of teams, exploring both the stage of team formation and the roles of individuals on both effective and ineffective teams. Then in Chapter 16 we talk about the fundamentals of managing a design project, including monitoring its progress and controlling its expenditures and costs. We finish our exploration of engineering design with our own capstone, Chapter 17, in which we discuss important ethics issues in design. This chapter reflects a wider notion of engineering ethics than in the past, as we invite faculty to address traditional notions of liability and responsibility and also newer ideas of social and political dimensions of engineering design.

DESIGN CASE STUDY AND INTEGRATIVE DESIGN EXAMPLES

We use one case study and two integrative examples to follow the design process through to completion, thus showing each of the tools and techniques as they are used on a design project. In addition to numerous “one-time” examples, we detail the following case study and integrative examples:

Finally, an accompanying Instructor's Manual includes a case study of the design of a transportation network to enable automobile commuter traffic between Boston and its northern suburbs, through Charlestown, Massachusetts. This conceptual design problem clearly illustrates the many factors that go into large-scale engineering projects in their early stages, when choices are being made between highways, tunnels, and bridges. Among the design concerns are cost, implications for future expansion, and preservation of the character, environment, and even the view of the affected neighborhoods. This project is also an example of how conceptual design thinking can significantly influence some very “real-world” events.

As noted at the outset, this edition has presented both an opportunity and a challenge for us as authors. We now share those with our readers.

Clive L. Dym                

Patrick Little                

Elizabeth J. Orwin       

Claremont, California

March 7, 2013