Budynas-Nisbett:Shigley's I.Basics 1.Introduction to T©The McGraw-Hill Mechanical Engineering Mechanical Engineering Companies,2008 Design,Eighth Edition Design Mechanical Engineering Design Mechanical design is a complex undertaking,requiring many skills.Extensive relation- ships need to be subdivided into a series of simple tasks.The complexity of the subject requires a sequence in which ideas are introduced and iterated. We first address the nature of design in general,and then mechanical engineering design in particular.Design is an iterative process with many interactive phases.Many resources exist to support the designer,including many sources of information and an abundance of computational design tools.The design engineer needs not only to develop competence in their field but must also cultivate a strong sense of responsibility and professional work ethic. There are roles to be played by codes and standards,ever-present economics,safety, and considerations of product liability.The survival of a mechanical component is often related through stress and strength.Matters of uncertainty are ever-present in engineer- ing design and are typically addressed by the design factor and factor of safety,either in the form of a deterministic (absolute)or statistical sense.The latter.statistical approach,deals with a design's reliabiliry and requires good statistical data. In mechanical design,other considerations include dimensions and tolerances, units,and calculations. The book consists of four parts.Part 1,Basics,begins by explaining some differ- ences between design and analysis and introducing some fundamental notions and approaches to design.It continues with three chapters reviewing material properties, stress analysis,and stiffness and deflection analysis,which are the key principles nec- essary for the remainder of the book. Part 2.Failure Prevention,consists of two chapters on the prevention of failure of mechanical parts.Why machine parts fail and how they can be designed to prevent fail- ure are difficult questions,and so we take two chapters to answer them,one on pre- venting failure due to static loads,and the other on preventing fatigue failure due to time-varying,cyclic loads. In Part 3,Design of Mechanical Elements,the material of Parts I and 2 is applied to the analysis,selection,and design of specific mechanical elements such as shafts, fasteners,weldments,springs,rolling contact bearings,film bearings,gears,belts, chains,and wire ropes. Part 4,Analysis Tools,provides introductions to two important methods used in mechanical design,finite element analysis and statistical analysis.This is optional study material,but some sections and examples in Parts I to 3 demonstrate the use of these tools. There are two appendixes at the end of the book.Appendix A contains many use- ful tables referenced throughout the book.Appendix B contains answers to selected end-of-chapter problems. 1-1 Design To design is either to formulate a plan for the satisfaction of a specified need or to solve a problem.If the plan results in the creation of something having a physical reality,then the product must be functional,safe,reliable,competitive,usable,manufacturable,and marketable. Design is an innovative and highly iterative process.It is also a decision-making process.Decisions sometimes have to be made with too little information,occasion- ally with just the right amount of information,or with an excess of partially contradictory information.Decisions are sometimes made tentatively,with the right reserved to adjust as more becomes known.The point is that the engineering designer has to be personally comfortable with a decision-making,problem-solving role.Budynas−Nisbett: Shigley’s Mechanical Engineering Design, Eighth Edition I. Basics 1. Introduction to Mechanical Engineering Design 10 © The McGraw−Hill Companies, 2008 4 Mechanical Engineering Design Mechanical design is a complex undertaking, requiring many skills. Extensive relation￾ships need to be subdivided into a series of simple tasks. The complexity of the subject requires a sequence in which ideas are introduced and iterated. We first address the nature of design in general, and then mechanical engineering design in particular. Design is an iterative process with many interactive phases. Many resources exist to support the designer, including many sources of information and an abundance of computational design tools. The design engineer needs not only to develop competence in their field but must also cultivate a strong sense of responsibility and professional work ethic. There are roles to be played by codes and standards, ever-present economics, safety, and considerations of product liability. The survival of a mechanical component is often related through stress and strength. Matters of uncertainty are ever-present in engineer￾ing design and are typically addressed by the design factor and factor of safety, either in the form of a deterministic (absolute) or statistical sense. The latter, statistical approach, deals with a design’s reliability and requires good statistical data. In mechanical design, other considerations include dimensions and tolerances, units, and calculations. The book consists of four parts. Part 1, Basics, begins by explaining some differ￾ences between design and analysis and introducing some fundamental notions and approaches to design. It continues with three chapters reviewing material properties, stress analysis, and stiffness and deflection analysis, which are the key principles nec￾essary for the remainder of the book. Part 2, Failure Prevention, consists of two chapters on the prevention of failure of mechanical parts. Why machine parts fail and how they can be designed to prevent fail￾ure are difficult questions, and so we take two chapters to answer them, one on pre￾venting failure due to static loads, and the other on preventing fatigue failure due to time-varying, cyclic loads. In Part 3, Design of Mechanical Elements, the material of Parts 1 and 2 is applied to the analysis, selection, and design of specific mechanical elements such as shafts, fasteners, weldments, springs, rolling contact bearings, film bearings, gears, belts, chains, and wire ropes. Part 4, Analysis Tools, provides introductions to two important methods used in mechanical design, finite element analysis and statistical analysis. This is optional study material, but some sections and examples in Parts 1 to 3 demonstrate the use of these tools. There are two appendixes at the end of the book. Appendix A contains many use￾ful tables referenced throughout the book. Appendix B contains answers to selected end-of-chapter problems. 1–1 Design To design is either to formulate a plan for the satisfaction of a specified need or to solve a problem. If the plan results in the creation of something having a physical reality, then the product must be functional, safe, reliable, competitive, usable, manufacturable, and marketable. Design is an innovative and highly iterative process. It is also a decision-making process. Decisions sometimes have to be made with too little information, occasion￾ally with just the right amount of information, or with an excess of partially contradictory information. Decisions are sometimes made tentatively, with the right reserved to adjust as more becomes known. The point is that the engineering designer has to be personally comfortable with a decision-making, problem-solving role