Engineering teams may be used as simply a means of dividing up the work-load. Similarly-trained engineers may be assigned specific design tasks by an engineering manager. In other instances, several engineers contribute special-ized knowledge and provide organizational competence to the solution of a problem where the knowledge of any one engineer would be inadequate to solve it.
When complex problems are faced, it may be desirable to establish a non-traditional organizational structure in which team members have a dual report-ing relationship to a functional manager or administrative supervisor as well as to a team leader. The design of an industrial plant, for example, may require the knowledge and skills of several types of engineers: industrial, chemical, civil, mechanical, and electrical. Members from each of the specialties could be assigned to a task force or a design team for the duration of the design process while reporting to a functional manager in their respective specialty as well as to the project engineer. Such design teams are often temporary and appointed for a specific purpose, then dissolved when the work is completed. (1)
T H E E N G I N E E R I N G M E T H O D
The nature of problems that must be solved by engineers varies both between and among the various branches of engineering. Indeed, an individual engineer may face a variety of problems during the course of his or her daily work activ-ities. Because of the variability of engineering designs, there is no definitive procedure or list of steps that will always fit the engineering problems at hand.
However, engineers tend to deal with problems in a special way. Certainly, the engineering method of approaching and solving problems differs greatly from that of most other professionals.1 Engineers are trained to think in analytical and objective terms and to approach problems methodically and systematically.
1It is, however, similar to the better-known “scientific method.”
A number of engineering writers have set forth a list of steps or phases that comprise the “engineering design method.” Typically, the list includes:
1. Identification of the problem.
2. Gathering needed information.
3. Searching for creative solutions.
4. Stepping from ideation to preliminary designs (including modeling).
5. Evaluation and selection of preferred solution.
6. Preparation of reports, plans, and specifications.
7. Implementation of the design.
As we describe these steps, it is important to keep in mind that in many instances, one or more of the steps may not appear. In other cases, it may be necessary to repeat the entire protocol several times in an attempt to converge on a desired solution. Let us now examine the various steps or phases of engi-neering design.
5.1 IDENTIFICATION OF THE PROBLEM
There is a tendency to think that this phase of the solution process is trivial and unimportant. Such is not the case. An incorrect or improper definition of the problem will cause the engineer to waste time and may lead to a solution that is inappropriate or incorrect. Pearson (2) states: “A problem properly defined is a problem partially solved. To state the problem correctly is a major step toward its solution.”
It is important that the stated needs be real needs. A truly great design may be worthless if it duplicates other known designs or if it solves a problem that does not impact many people. If it is a product that is being designed, it may be difficult to predict the mass appeal and the resulting marketability of a proposed design. A preliminary market analysis will usually identify the prospective users and statistics about comparable devices or methods and volume of sales.
The needs to be satisfied should be broadly defined and distinguished from possible solutions. In this phase, care should be taken not to prejudice the solu-tion by incorrectly defining the problem. Consider the following example.
For decades in the United States, deaths of drivers and passengers in motor vehicle crashes were considered to be one of the nation’s most serious public health problems. Traffic safety specialists defined the problem in terms of acci-dent prevention rather than loss reduction. They spoke in terms of a need to pre-vent accidents rather than a need to reduce losses from accidents. In so doing, they presupposed the problem solution and focused their attention exclusively on driver behavior. Predictably, their “solution” to the problem was driver edu-cation, traffic enforcement, and “Drive Safely” campaigns. They overlooked pos-sible benefits from more crashworthy vehicles and a safer roadway environment.
To the extent possible, the problem should be defined in objective terms.
Here is an example of a problem that is defined in objective terms.
5.1 IDENTIFICATION OF THE PROBLEM
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Design an energy attenuation system that will control the energy of a crash of a 2500-pound car traveling 60 miles per hour at impact. The device should not be longer than 10 feet and should cost no more than $10,000 per unit. The deceleration should not exceed 6 gs (193 ft/s2).
Contrast this definition with the following situation:
Design an energy attenuation system that will control the energy of a car traveling at a fast speed at impact. The device should be short and inexpensive to build. The deceleration should not be harmful to the driver.
Finally, the problem should not be unnecessarily constrained. If too many constraints are placed on the problem, it may make its solution extremely dif-ficult or even impossible. In fact, a careful examination of the example prob-lem stated above in light of Newton’s second law of mechanics shows that it is overconstrained. The device would need to be longer than 10 feet to meet the other conditions of the problem.
5.2 GATHERING NEEDED INFORMATION
Once the problem is identified and the needs properly defined, the engineer then begins to gather information and data needed to solve it. The type of infor-mation needed will, of course, depend on the nature of the problem to be solved. It could be physical measurements, maps, results of laboratory experi-ments, patents, results of opinion surveys, or any of a number of other types of information. This phase of the problem-solving process involves gathering and evaluating information that is already available. If the engineer is employed by a large corporation or a public agency, it will probably be desirable to search old files and interview other employees to see if others have undertaken simi-lar work. Subsequently, it may be necessary to supplement this information by making additional measurements or conducting more laboratory experiments, opinion surveys, and the like.
In this phase of the process, engineers typically undertake a literature search to determine what others have learned about related problems. They may visit technical libraries and study textbooks, journal articles, and manufacturers’
catalogs. Librarians can be very helpful in locating textbooks and journal ref-erences, and most libraries now have access to computer-aided searching ser-vices that are fast and relatively inexpensive. Some libraries also maintain manufacturers’ catalogs reduced onto microfiche film with a subject index to help in locating already-manufactured components.
Finally, it is worthwhile to perform a patent search, especially if there is a patent library nearby. Most “mouse traps” never make it to market or to press;
consequently, there are many great designs described in intricate legal detail, which can be found in the chronological listing of U.S. patents.
5.3 SEARCHING FOR CREATIVE SOLUTIONS
After completing the preparatory steps in the design process, the engineer is ready to begin identifying creative solutions. Actually, the development of new
ideas, products, or devices may result from creativity, a subconscious effort, or from innovation, a conscious effort.
There are several operational techniques that may be used to help a group or individual to produce original ideas. These techniques are designed to enable the group or individual to overcome obstacles to creative thinking such as those described in Chapter 4.
Brainstorming
One of the most popular techniques for group problem solving is brainstorm-ing. Typically, a brainstorming session consists of 6 to 12 people who sponta-neously introduce ideas designed to solve a specific problem. In these sessions, all ideas are encouraged, including those that appear to be completely imprac-tical. Efforts are made to generate as many ideas as possible. Participants are encouraged to combine or improve on ideas of others. Judgment and evaluation of the ideas are not permitted in the idea-producing session.
It is suggested that participants in brainstorming sessions be chosen from a diversity of backgrounds and that people with little direct experience with the problem be included. Brainstorming sessions usually last not longer than one hour. Ideas produced by a brainstorming session are recorded and evaluated at a later time by the brainstorming group or by another group or individual.
A form of the brainstorming technique can also be used by an individual.
The individual follows the same rules used for a group session: combination of ideas, postponement of evaluation, and an emphasis on obtaining a large num-ber of ideas. The individual brainstorming session need not take more than a few minutes. Again, the ideas are recorded and evaluated at a later time.
Checklists
One of the simplest ideas for generating new ideas is to make a checklist. The checklist encourages the user to examine various points, areas, and design pos-sibilities. For example, suppose that you were attempting to improve a certain device. You might make a checklist that includes:
Ways the device could be put to other uses.
Ways the device could be modified.
Ways the device could be rearranged.
Ways the device could be magnified.
Ways the device could be lessened, and so on.