All engineers who are concerned with the development of products or the design of machines and structures must be knowledgeable about the materials from which they are made. After all, the selection of the correct material for a design is a key step in the design process because it is the crucial decision that links the computer calculations and the lines on an engineering drawing with a working design. At the same time, the rapid progress in materials science and engineering has made a large number of materials—metals, polymers, ceramics, and composites—of potential interest to the designer. Thus, the range of materials available to the engineer is much larger than ever before. This presents the opportunity for innovation in design by utilizing these materials in products that provide greater performance at lower cost. To achieve this requires a more rational process for materials selection than is normally used.
Materials engineers have traditionally been involved in helping to select materials. In most cases, this is done more or less in isolation from the actual design process. Sometimes the materials expert becomes involved only when the design fails. In the past ten years, mostly in response to the pressures of international competitiveness, new approaches to product design and development have arisen to improve quality, drive down cost, and reduce product cycle time. Generally called concurrent engineering, it uses product development teams of experts from all functions—design, manufacturing, marketing, and so forth—to work together from the start of the product design project. This opens new opportunities for better material selection. It also has resulted in the development of new computer-based design tools. If materials engineers are to play an important future role in product development, they need to be more familiar with the design process and these design tools.
Thus, Volume 20 of ASM Handbook is aimed at two important groups: materials professionals and design professionals. As a handbook on materials selection and design, it is unique. No other handbook deals with this subject area in this way, bridging the gaps between two vital but often distant areas of expertise. The Handbook is divided into seven sections:
The Design Process
Criteria and Concepts in Design
The Materials Selection Process
Effects of Composition, Processing, and Structure on Materials Properties
Properties versus Performance of Materials
Manufacturing Aspects of Design
Emphasis throughout is on concepts and principles, amply supported by examples and case histories. This is not a handbook of material property data, nor is it a place to find detailed discussion of specific material selection problems. Other volumes in the ASM Handbook series often provide this type of information.
Section 1, “The Design Process,” sets the stage for the materials engineer to better understand and participate in the product design process. The context of design within a manufacturing firm is described, and the role of the materials engineer in design is discussed. Emphasis is placed on methods for conceptual and configuration design, including the development of a product specification. Methods for creative generation of conceptual designs and for evaluation of conceptual and configuration alternatives are introduced. Learning to work effectively in cross-functional teams is discussed.
Section 2, “Criteria and Concepts in Design” deals with design concepts and methods that are important for a complete understanding of engineering design. The list is long: concurrent engineering, including QFD; codes and standards; statistical aspects of design; reliability in design; life-cycle engineering; design for quality; robust design (the Taguchi approach); risk and hazard analysis; human factors in design; design for the environment (green design); safety; and product liability and design.
Section 3 considers “Design Tools.” This section provides an overview of the computer-aided engineering tools that are finding wide usage in product design. This includes the fundamentals of computer-aided design, and the use of computer-based methods in mechanism dynamics, stress analysis (finite element analysis), fluid and heat transfer analysis, and electronic design. Also considered are computer methods for design optimization and tolerance analysis. Finally, the section ends with discussions of the document packages necessary for design and of methods for rapid prototyping.
Section 4, “The Materials Selection Process,” lays out the complexity of the materials selection problem and describes various methodologies for the selection of materials. Included are Ashby's material property charts and performance indices, the use of decision matrices, and computer-aided methods. Also discussed are the use that can be made of value analysis and failure analysis in solving a materials selection problem. The close interrelationship of materials selection and economic issues and processing are reinforced in separate articles.
Section 5, “Effects of Composition, Processing, and Structure on Materials Properties,” is aimed chiefly at the design engineer who is not a materials specialist. It is a “mini-textbook” on materials science and engineering, with a strong engineering flavor and oriented chiefly at explaining mechanical properties and behavior in terms of structure. The role that processing plays in influencing structure is given emphasis. The articles in this Section cover metallic alloys, ceramics, engineering plastics, and composite materials. The Section concludes with an article on places to find materials information and properties.
Section 6, “Properties versus Performance of Materials,” features articles that attempt to cross the materials/design gap in a way that the designer will understand how the material controls properties and the materials engineer will become more familiar with real-world operating conditions. Again, emphasis is mostly on mechanical behavior and includes articles on design for static structures, fatigue, fracture toughness, and high temperature. Other articles consider design for corrosion resistance, oxidation, wear, and electronic and magnetic applications. Separate articles consider the special concerns when designing with brittle materials, plastics, and composite materials.
Section 7, “Manufacturing Aspects of Design,” focuses on the effects of manufacturing processes on the properties and the costs of product designs. The section contains articles on design for manufacture and assembly (DFM and DFA), general guidelines for selecting processes, modeling of processes, and cost estimation in manufacturing. Individual articles deal with design for casting, deformation processes, powder processing, machining, joining, heat treatment, residual stresses, and surface finishing. Articles also deal with design for ceramic processing, plastics processing, and composite manufacture.
This Handbook would not have been possible without the dedicated hard work of the chairmen of the sections: John R. Dixon, University of Massachusetts (retired); Bruce Boardman, Deere & Company; Kenneth H. Huebner, Ford Motor Company; Richard W. Heckel, Michigan Technological University (retired); David A. Woodford, Materials Performance analysis Inc.; and Howard A. Kuhn, Concurrent Technologies Corporation. Special thanks goes to several individuals who did work well beyond the normal call of duty in reviewing manuscripts: Serope Kalpakjian, John A. Schey, and Charles O. Smith. I wish to thank all of the busy people who agreed to author articles for the Handbook. The high rate of acceptance, from both the design community and the materials community, is a strong indicator of the importance of the need that ASM Handbook, Volume 20, fills.
George E. Dieter
University of Maryland
University of Maryland