THE DESIGN PROCESS
The basic five-step process usually used in a problem-solving works for design problems as well. Since design problems are usually defined more vaguely and have a multitude of correct answers, the process may require backtracking and iteration. Solving a design problem is a contingent process and the solution is subject to unforeseen complications and changes as it develops. Until the Wright brothers actually built and tested their early gliders, they did not know the problems and difficulties they would face controlling a powered plane.
The five steps used for solving design problems are:
- Define the problem
- Gather pertinent information
- Generate multiple solutions
- Analyze and select a solution
- Test and implement the solutionSo your design can meet us at any of the stages maybe design and simulation of a system or from the idea level this is just for you to see the different stages that is involved in the design process.
The first step in the design process is the problem definition. This definition usually contains a listing of the product or customer requirements and specially information about product functions and features among other things. In the next step, relevant information for the design of the product and its functional specifications is obtained.
this stage. Once the details of the design are clearly identified, the design team with inputs from test, manufacturing, and marketing teams generates multiple alternatives to achieve the goals and the requirements of the design. Considering cost, safety, and other criteria for selection, the more promising alternatives are selected for further analysis. Detail design and analysis step enables a complete study of the solutions and result in identification of the final design that best fits the product requirements. Following this step, a prototype of the design is constructed and functional tests are performed to verify and possibly modify the design.
When solving a design problem, you may find at any point in the process that you need to go back to a previous step. The solution you chose may prove unworkable for any number of reasons and may require redefining the problem, collecting more information, or generating different solutions. This continuous iterative process is represented in the following Figure.
- DEFINE THE PROBLEM
You need to begin the solution to a design problem with a clear, unambiguous definition of the problem. Unlike an analysis problem, a design problem often begins as a vague, abstract idea in the mind of the designer. Creating a clear definition of a design problem is more difficult than, defining an analysis problem. The definition of a design problem may evolve through a series of steps or processes as you develop a more complete understanding of the problem.
Identify and Establish the Need Engineering design activity always occurs in response to a human need. Before you can develop a problem definition statement for a design problem, you need to recognize the need for a new product, system, or machine. Thomas Newcomen saw the need for a machine to pump the water from the bottom of coal mines in England. Recognizing this human need provided him the stimulus for designing the first steam engine in 1712. Before engineers can clearly define a design problem, they must see and understand this need.
Although engineers are generally involved in defining the problem, they may not be the ones who initially recognize the need. In private industry, market forces generally establish the need for a new design. A company’s survival depends on producing a product that people will buy and can be manufactured and sold at a profit. Ultimately, consumers establish a need, because they will purchase and use a product that they perceive as meeting a need for comfort, health, recreation, transportation, shelter, and so on. Likewise, the citizens of a government decide whether they need safe drinking water, roads and highways, libraries, schools, fire protection, and so on.
Develop a Problem Statement
The first step in the problem-solving process, therefore, is to formulate the problem in clear and unambiguous terms. Defining the problem is not the same as recognizing a need. The problem definition statement results from first identifying a need. The engineer at the airbag company responded to a need to reduce the number of airbag inflation failures. He made a mistake, however, in not formulating a clear definition of the problem before generating a solution. Once a need has been established, engineers define that need in terms of an engineering design problem statement. To reach a clear definition, they collect data, run experiments, and perform computations that allow that need to be expressed as part of an engineering problem-solving process.
- GATHER PERTINENT INFORMATION
Before you can go further in the design process, you need to collect all the information available that relates to the problem. Novice designers will quickly skip over this step and proceed to the generation of alternative solutions. You will find, however, that effort
spent searching for information about your problem will pay big dividends later in the design process. Gathering pertinent information can reveal facts about the problem that result in a redefinition of the problem. You may discover mistakes and false starts made by other designers. Information gathering for most design problems begins with asking the following questions. If the problem addresses a need that is new, then there are no existing solutions to the problems, so obviously some of the questions would not be asked.
- Is the problem real and its statement accurate?
- Is there really a need for a new solution or has the problem already been solved?
- What are the existing solutions to the problem?
- What is wrong with the way the problem is currently being solved?
- What is right about the way the problem is currently being solved?
- What companies manufacture the existing solution to the problem?
- What are the economic factors governing the solution?
- How much will people pay for a solution to the problem?
- What other factors are important to the problem solution (such as safety, aesthetics and environmental issues)?
- GENERATE MULTIPLE SOLUTIONS
The next step in the design process begins with creativity in generating new ideas that may solve the problem. Creativity is much more than just a systematic application of rules and theory to solve a technical problem.
You start with existing solutions to the problem and then tear them apart-find out what’s wrong with those solutions and focus on how to improve their weaknesses. Consciously combine new ideas, tools, and methods to produce a totally unique solution to the problem. This process is called synthesis
Psychological research has found no correlation between intelligence and creativity. People are creative because they make a conscious effort to think and act creatively. Everybody has the potential to be creative. Creativity begins with a decision to take risks. Listed below are a few characteristics of creative people. These are not rigid rules to be followed to experience creativity. You can improve your creative ability by choosing to develop these characteristics in yourself.
Analysis of Design Solutions Before deciding which design solution to implement, you need to analyze each alternative solution against the selection criteria defined in step l. You should perform several types of analysis on each design. Every design problem is unique and requires different types of analysis. The following is a list of analysis that may need to be considered; bear in mind that the importance of each varies depending on the nature of the problem and the solution.
- Functional analysis • Industrial design/Ergonomics • Mechanical/Strength analysis • Electrical/Electromagnetic • Manufacturability/Testability • Product safety and liability • Economic and market analysis • Regulatory and Compliance
The following paragraphs provide details of some of these analysis types.
Functional analysis. This part determines whether the given design solution will function the way it should. Functional analysis is fundamental to the evaluation and success of all designs. A design solution that does not function properly is a failure even if it meets all other criteria. Consider for example the invention of the ballpoint pen. This common instrument was first invented and manufactured during World War II. The ballpoint pen was supposed to solve the problems of refilling and messiness inherent to the fountain pen. Unfortunately, this new design had never been evaluated for functionality. The early pens depended on gravity for the ink to flow to the roller ball. This meant that the pens only worked in a vertical upright position, and the ink flow was inconsistent: Sometimes it flowed too heavily, leaving smudgy blotches on the paper; other times the flow was too light and the markings were unreadable. The first ballpoint pens tended to leak around the ball, ruining people’s clothes. An elastic ink developed in 1949, allowed the ink to flow over the ball through smooth capillary action. Not until the 1950s did the ballpoint pen finally become a practical writing instrument, thanks to proper ink and engineering. Economy, appearance, durability, and marketability of a design are unimportant if the product does not function properly.
Ergonomics. Ergonomics is the human factor in engineering. It is the study of how people interact with machines. Most products have to work with people in some manner. People occupy a space in or around the design, and they may provide a source of power or control or act as a sensor for the design. For example, people sense if an automobile air-conditioning system is maintaining a comfortable temperature inside the car. These factors form the basis for human factors, or ergonomics, of a design.
A design solution can be considered successful if the design fits the people using it. The handle of a power tool must fit the hand of everybody using it. The tool must not be too
heavy or cumbersome to be manipulated by all sizes of people using the tool. The geometric properties of people-their weight, height, reach, circumference, and so on-are called anthropometric data. The difficulty in designing for ergonomics is the abundance of anthropometric data. The military has collected and evaluated the distribution of human beings and published this information in military standard tables. A successful design needs to be evaluated and analyzed against the distribution of geometry of the people using it. The following Figure shows the geometry of typical adult males and females for the general population in millimeters. Since people come in different sizes and shapes, such data are used by design engineers to assure that their design fits the user. A good design will be adjustable enough to fit 95 percent of the people who will use it.
- Curiosity and tolerance of the unknown. Creative people have a positive curiosity of the unknown. They are not afraid of what they don’t understand.
- • Openness to new experiences. Creative people have a healthy and positive attitude toward new experiences.
- • Willingness to take risks. Creative people are not afraid to take risks and try new experiences or ideas, knowing that they may be misunderstood and criticized by others. They are self-confident and not afraid to fail.
- • Ability to observe details and see the “whole picture.” Creative people notice and observe details relating to the problem, but they also can step back and see the bigger picture.
- • No fear of problems. Creative people are not afraid to tackle complex problems, and they even search for problems to solve. They seek solutions to problems with their own abilities and experience if possible. They have the attitude of “if you want something done, you’d better do it yourself.”
- • Ability to concentrate and focus on the problem until it’s solved. Creative people can set goals and stick to them until they’re reached. They focus on a problem and do not give up until the problem is solved. They have persistence and tenacity.
Solutions to engineering design problems do not magically appear. Ideas are generated when people are free to take risks and make mistakes. Brainstorming at this stage is often a team effort in which people from different disciplines are involved in generating multiple solutions to the problem.