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Materials Selection in Mechanical Design

‘Design’ is one of those words that means all things to all people. Every manufactured thing, from the most lyrical of ladies’ hats to the greasiest of gearboxes, qualifies, in some sense or other, as a design. It can mean yet more. Nature, to some is Divine Design; to others it is design by Natural Selection, the ultimate genetic algorithm. The reader will agree that it is necessary to narrow the field, at least a little. This book is about | Chapter 1__ Introduction 1.1 Introduction and synopsis Design is one of those words that means all things to all people. Every manufactured thing from the most lyrical of ladies hats to the greasiest of gearboxes qualifies in some sense or other as a design. It can mean yet more. Nature to some is Divine Design to others it is design by Natural Selection the ultimate genetic algorithm. The reader will agree that it is necessary to narrow the field at least a little. This book is about mechanical design and the role of materials in it. Mechanical components have mass they carry loads they conduct heat and electricity they are exposed to wear and to corrosive environments they are made of one or more materials they have shape and they must be manufactured Figure 1.1 . The book describes how these activities are related. Materials have limited design since man first made clothes built shelters and waged wars. They still do. But materials and processes to shape them are developing faster now than at any previous time in history the challenges and opportunities they present are greater than ever before. The book develops a strategy for exploiting materials in design. 1.2 Materials in design Design is the process of translating a new idea or a market need into the detailed information from which a product can be manufactured. Each of its stages requires decisions about the materials from which the product is to be made and the process for making it. Normally the choice of material is dictated by the design. But sometimes it is the other way round the new product or the evolution of the existing one was suggested or made possible by the new material. The number of materials available to the engineer is vast something between 40 000 and 80 000 are at his or her from here on his means both disposal. And although standardization strives to reduce the number the continuing appearance of new materials with novel exploitable properties expands the .