1、Design Invention CreativityThese are all familiar terms but may mean different things to different people. These terms can encompass a wide range of activities from styling the newest look in clothing, to creating impressive architecture, to engineering a machine for the manufacture of facial tissue
2、s. Engineering design, which we are concerned with here, embodies all three of these activities as well as many others. The word design is derived from the Latin designare, which means “to designate, or mark out.” Websters gives several definitions, the most applicable being “to outline, plot, or pl
3、an, as action or workto conceive, invent-contrive.” Engineering design has been defined as “.the process of applying the various techniques and scientific principles for the purpose of defining a device, a process or a system in sufficient detail to permit its realization.Design may be simple or eno
4、rmously complex, easy or difficult, mathematical or nonmathematical; it may involve a trivial problem or one of great importance.” Design is a universal constituent of engineering practice. But the complexity of engineering subjects usually requires that the student be served with a collection of st
5、ructured, set-piece problems designed to elucidate a particular concept or concepts related to the particular topic. These textbook problems typically take the form of “given A, B, C, and D, find E.” Unfortunately, real-life engineering problems are almost never so structured. Read design problems m
6、ore often take the form of “What we need is a framus to stuff this widget into that hole within the time allocated to the transfer of this other gizmo.” The new engineering graduate will search in vain among his or her textbooks for much guidance to solve such a problem. This unstructured problem st
7、atement usually leads to what is commonly called “blank paper syndrome.” Engineers often find themselves staring at a blank sheet of paper pondering how to begin solving such an ill-defined problem. Much of engineering education deals with topics of analysis, which means to decompose, to take apart,
8、 to resolve into its constituent parts. This is quite necessary. The engineer must know how to analyze systems of various types, mechanical, electrical, thermal or fluid. Analysis requires a thorough understanding of both the appropriate mathematical techniques and the fundamental physics of the sys
9、tems function. But, before any system can be analyzed, it must exist, and a blank sheet of paper provides little substance for analysis. Thus the first step in any engineering design exercise is that of synthesis, which means putting together.The design engineer, in practice, regardless of disciplin
10、e, continuously faces the challenge of structuring the unstructured problem. Inevitably, the problem as posed to the engineer is ill-defined and incomplete. Before any attempt can be made to analyze the situation he or she must first carefully define the problem, using an engineering approach. To en
11、sure that any proposed solution will solve the right problem. Many examples exist of excellent engineering solutions which were ultimately rejected because they solved the wrong problem, i.e., a different one than the client really had.Much research has been devoted to the definition of various “des
12、ign processes” intended to provide means to structure the unstructured problem and lead to a viable solution. Some of these processes present dozens of steps, others only a few. The one presented in table 1-1 contains 10 steps and has, in the authors experience, proven successful in over 30 years of
13、 practice in engineering design. ITERATION Before discussing each of these steps in detail it is necessary to point out that this is not a process in which one proceeds from step one through ten in a linear fashion. Rather it is, by its nature, an iterative process in which progress is made haltingl
14、y, two steps forward and one step back. It is inherently circular. To iterate means to repeat, to return to a previous state. If, for example, your apparently great idea, upon analysis, turns out to violate the second law of thermodynamics, you can return to the ideation step and get a better idea!
15、Or, if necessary, you can return to an earlier step in the process, perhaps the background research, and learn more about the problem. With the understanding that the actual execution of the process involves iteration, for simplicity, we will now discuss each step in the order listed in table 1-1.Id
16、entification of NeedThis first step is often done for you by someone, boss or client, saying “What we need is.” Typically this statement will be brief and lacking in detail. It will fall far short of providing you with a structured problem statement. For example, the problem statement might be “We n
17、eed a better lawn mower.”Background researchThis is the most important phase in the process, and is unfortunately often the most neglected. The term research, used in this context, should not conjure up visions of white-coated scientists mixing concoctions in test tubes. Rather this is research of a
18、 more mundane sort, gathering background information on the relevant physics, chemistry, or other aspects of the problem. Also it is desirable to find out if this, or a similar problem, has been solved before. There is no point in reinventing the wheel. If you are lucky enough to find a ready-made s
19、olution on the market, it will no doubt be more economical to purchase it than to build your own. Most likely this will not be the case, but you may learn a great deal about the problem to be solved by investigating the existing “art” associated with similar technologies and products. The patent lit
20、erature and technical publications in the subject area are obvious sources of information and are accessible via the worldwide web. Clearly, if you find that the solution exists and is covered by a patent design something which does not conflict with the patent, or drop the project. It is very phase
21、 of the process in order to avoid the embarrassment of concocting a great solution little attention to this phase and jump too quickly into the ideation and invention stage of the process. This must be avoided! You must discipline yourself to not try to solve the problem before thoroughly preparing
22、yourself to do so.Goal StatementOnce the background of the problem area as originally stated is fully understood, you will be ready to recast that problem into a more coherent goal statement. This new problem statement should have three characteristics. It should be concise, be general, and be uncol
23、ored by any terms which predict a solution. It should be couched in terms of functional visualization, meaning to visualize its function, rather than any particular embodiment. For example, if the original statement of need was “Design a Better Lawn Mower,” after research into the myriad of ways to
24、cut grass that have been devised over the ages, the wise designer might restate the goal as “Design a Means to Shorten Grass.” The original problem statement has a built-in trap in the form of the colored words “lawn mower.” For most people, this phrase will conjure up a vision of something with whi
25、rring blades and a noisy engine. For the ideation phase to be most successful, it is necessary to avoid such images and to state the problem generally, clearly, and concisely. As an exercise, list 10 ways to shorten grass. Most of them would not occur to you had you been asked for 10 better lawn mow
26、er designs. You should use functional visualization to avoid unnecessarily limiting your creativity!Performance SpecificationsWhen the background is understood, and the goal clearly stated, you are ready to formulate a set of performance specifications. These should not be design specifications. The
27、 difference is that performance specifications define what the system must do, while design specifications define how it must do it. At this stage of the design process it is unwise to attempt to specify how the goal is to be accomplished. That is left for the ideation phase. The purpose of the perf
28、ormance specifications is to carefully define and constrain the problem so that it both can be solved and can be shown to have been solved after the fact. A sample set of performance specifications for our “grass shortener” is shown in Table 1-2. TABLE 1-2 Performance Specifications1 Device to have
29、self-contained power supply. 2 Device to be corrosion resistant.3 Device to cost less than 100.00.4 Device to emit 80 dB sound intensity at 50 feet.5 Device to shorten 1/4 acre of grass per hour. 6 etc.etc. Note that these specifications constrain the design without overly restricting the engineers
30、design freedom. It would be inappropriate to require a gasoline engine for specification 1, since other possibilities exist which will provide the desired mobility. Likewise, to demand stainless steel for all components in specification 2 would be unwise, since corrosion resistance can be obtained b
31、y other, less-expensive means. In short, the performance specifications serve to define the problem in as complete and as general a manner as possible, and they serve as a contractual definition of what is to be accomplished. The finished design can be tested for compliance with the specifications.I
32、deation and InventionThis step is full of both fun and frustration. This phase is potentially the most satisfying to most designers, but it is also the most difficult. A great deal of research has been done to explore the phenomenon of “creativity.” It is, most D, a common human trait. It is certainly exhibited to a very high degree by all young children. The rate and degree of development that occurs in the human from birth through the first few years of life certainly requires some innate creativity. Some have claimed that our methods of Western education tend to stifle chil
