Book Description

Principles of Computer-Aided Design and Manufacturingis the product of many years of experience teaching courses in computer-aided design (CAD). My first book, published in 1991, was a challenge—the technology was evolving and both the hardware and software were changing rapidly. Since then we have come a long way in the CAD/CAM area, and the prospects are even better for future intelligent systems that will enable engineers to design engineering products more efficiently. From design to development, we are attaining some great achievements that will engineer products that are more competitive and ready to meet the market needs. In essence, CAD will provide the engineer more time for the creative aspects in terms of concept formulation and interpretation of the results derived from the analysis. The tools of CAD/CAM are now more standardized and most of our students today come equipped with the basic engineering graphics knowledge needed to learn advanced engineering tools. Having gone through the experience of teaching this course and at the same time trying to adapt to the changing needs in the laboratory, I have written this book under the premise of providing the students the fundamentals needed to advance their understanding of design, analysis, and product development in manufacturing. The latter is achieved through selection of appropriate topics and analytical methods in all aspects of design that are pertinent to CAD with the hope that students will embrace them with conviction. These topics are written in a clear and concise form, and are followed by examples to guide the students and engineers through a wonderful learning experience. The thrust behind learning and teaching CAD is the ability to reach a level of confidence that will enable oneself to interact with ease with the existing CAD systems to solve engineering problems. My philosophy is to teach through examples; hence, every topic covered is followed by examples to demonstrate the concepts. The basic engineering concepts learned in this book are independent of any specific software. We are at a stage now in which CAD/CAM does not necessary have to be self-contained. Rather, students should be able to use other tools to link or provide additional information as necessary to the CAD system. Where some topics could be supplemented, I have taken the liberty in this textbook of allowing the students to perform their exercises using MATLAB for the sake of understanding that CAD is a multidiscipline in nature and some parts of the design or analysis can be programmed in other languages. This is becoming a common practice as vendors are making it simpler and easier to transport files from different systems, and in some cases even be able to integrate different analysis tools to provide the students and engineers the ability to interact with their software to meet their engineering needs. This is certainly true in the variational design and parametric designs areas in which engineering equations are the engine behind the geometrical formulation and design of certain products. This textbook is written to satisfy the CAD requirements courses even though finite element coverage expands beyond the introduction of truss analysis. It is difficult to cover all topics in one semester. Topics should be selected to meet the course needs and the laboratory requirements that go with it. For example, at the University of Illinois at Chicago, we have a required laboratory part of the course where students are given different projects on weekly basis to become proficient in the use of CAD software such as ProE or IDEAS. The last lab projects are more involved and usually require some forms of analysis and animation. My intention is to provide additional topics in finite elements that will allow the instructor to focus not only on simple trusses but also be able to teach heat conduction, basic principles in FEM, and even vibration to broaden the scope of analysis. The idea is one that allows our senior students to be exposed to FEM by combining most of what they have learned and show how it can be done with the help of this powerful technique of FEM. This has been very successful with our undergraduate students and first-year graduate students because they are able to use this textbook to learn the basic concepts required in analysis to be able to use finite element tools such as ANSYS, IDEAS, and CATIA, among others. The book is divided into 15 chapters and provides a unique balance of topics that cover design, 3D transformation and geometry manipulation, surface creations, solid modeling, optimization, finite elements, robotics and robot economics, and CAM implementation. Chapter 1 provides a historical perspective of CAD and discusses virtual reality as it is used in our current engineering environment (the latter is a topic that will need to be explored further down the road). Chapter 2 addresses the different stages in design and provides concrete examples showing how these steps can be accomplished. The unique feature of this chapter is the parametric and variational design concept. In this textbook I have made an effort to enlighten the students with the need for these techniques to be taken seriously as they might become standard in the near future. The blending of man and machine is an effective tool when CAD systems are allowed to participate in the design and manufacturing process by aiding in the problem formulation, synthesis, conceptualization, and, of course, analysis. Once the students have had some exposure to CAD in general, Chapter 2 could be covered at any part of the course. I urge the instructors and readers to take the time and go over these examples and to create their own examples to appreciate the benefits of these tools. Chapter 3 discusses 2D and 3D transformations and geometry manipulation, and provides an in-depth analysis of images in 2D and 3D, and includes isometric views. Chapter 4 explains the fundamentals underlying splines, parametric and nonparametric curves, and Bezier curves and surfaces. A number of examples are included to assist the students in understanding how the concepts are implemented. Depending on how advanced the students are, selected topics can be skipped or simply assigned as additional material for the class. Chapter 5 introduces the concept of solid modeling and the various construction techniques and representation schemes in modeling. The students will apply some of these concepts in their lab work working with the making of solid models in CAD. Chapter 6 covers various techniques of optimization and introduces the students to the basic concepts of how to formulate an objective function, define the appropriate constraints, and choose the analytical tools to solve the problem. This chapter also focuses on popular techniques in optimization so that senior students and first-year graduate students will have some familiarity with their use. Chapters 7 through 10 form a unique combination of teaching the finite element method to our junior and senior students without the burden of heavy calculus. It is one of the major strengths of this textbook. If a curriculum is more focused on analysis, all chapters can be covered; otherwise, the instructor is given the choice of covering FEM by selecting the appropriate topics) for the class. This would include stress analysis, heat conduction, dynamic analysis, and vibration, or simply teaching the basic formulation of FEM as described in Chapter 7. The examples solved in these chapters represent real applications and will encourage the students to develop a good appetite for FEM. Computer-aided manufacturing is introduced in Chapters 11 through 15. I have opted to focus on key topics of interest to the students such as robotics and economic impact, group technology, and computer-integrated manufacturing. These are some of the features that need to be understood in the integration of CAD and CAM. Principles of Computer-Aided Design and Manufacturingis written for junior and senior level students and first-year graduate students who have had little exposure to computer-aided design. This textbook assumes that the students have some experience with programming and understand basic concepts in CAD found in a freshman course of graphics. This textbook is suitable for students who have had all their undergraduate requirements in their major. The latter is an incentive whereby students will fully appreciate the benefits of design techniques such as parametric and variational design and develop a deep understanding of how FEM works and how it is applied to various engineering applications. I am indebted to the reviewers for their useful comments and suggestions, which helped shape the content and focus of this book: Dr. Heana Costea, California State University at Northridge; Derek M. Yip-Hoi, University of Michigan at Ann Arbor; and Gregory Kremer, Ohio State University. I would also like to thank Dr. M. Ayub, visiting professor in the Civil Engineering Department at University of Chicago at Illinois, for taking the time to edit several chapters and provide his insight for the book and M. Arif, associate professor in the Civil Engineering Department at University of Chicago at Illinois, for his encouragement and support. The comments and suggestions of the reviewers were instrumental in my final revision and in selecting additional topics that were missing from the original proposal. They kindly helped review my original manuscript and assisted me in looking at their course focus and syllabus to get a better picture of how the CAD course is taught at their respective institutions. Finally, I am indebted to all my students who have assisted me in the preparation of necessary materials for this book; without their help, this wouldn't have been possible. In particular, I would like to thank Carlos Lopez for his efforts on the parametric and variational designs section of the book. I also like to thank Francisco Romero, Nagarajan Chandra, Pedro Gonzalez, and David McNeil for their genuine effort in assisting with some of the graphics of the book. I would like to thank Nikhil Khulka and Ivan Zivkovic for being there when I needed them the most to meet the publisher deadlines and organize the chapters and figures selected for the book. I also would like to thank Surya Pratar for helping with indexing of this book. Finally, let me take this opportunity to thank the editorial staff, Dorothy Marrero, David George, and Lynda Castillo at Prentice Hall, for their patience during the course of the production of the book. I had the pleasure of working closely with Kevin Bradley at Sunflower Publishing Services, who oversaw the complete publication of the book. He was kind and very responsive to all my questions. He worked intelligently to make sure I was happy with the changes and the editing of my book. At the end I would like to thank my family, Ginger, Larby, and Anissa, for their unconditional love and support and for their understanding in the sacrifices we make in achieving our objectives. In particular, I would like to thank my mom and dad for giving me hope, guidance, and values to treasure for years to come. FARID AMIROUCHE The Department of Mechanical & Industrial Engineering University of Illinois, Chicago