Engineering design process
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The engineering design process is a methodical series of steps that engineers use in creating functional products and processes. The process is highly iterative - parts of the process often need to be repeated many times before production phase can be entered - though the part(s) that get iterated and the number of such cycles in any given project can be highly variable.
…It is a decision making process (often iterative) in which the basic sciences, mathematics, and engineering sciences are applied to convert resources optimally to meet a stated objective. Among the fundamental elements of the design process are the establishment of objectives and criteria, synthesis, analysis, construction, testing and evaluation
One framing of the engineering design process delineates the following stages: research, conceptualization, feasibility assessment, establishing design requirements, preliminary design, detailed design, production planning and tool design, and production. The steps tend to get articulated, subdivided, and/or illustrated in a variety of different ways, but they generally reflect certain core principles regarding the underlying concepts and their respective sequence and interrelationship.
Common Stages of the Engineering Design Process
A significant amount of time is spent on locating information and research. Consideration should be given to the existing applicable literature, problems and successes associated with existing solutions, costs, and marketplace needs.
The source of information should be relevant, including existing solutions. Reverse engineering can be an effective technique if other solutions are available on the market. Other sources of information include the Internet, local libraries, available government documents, personal organizations, trade journals, vendor catalogs and individual experts available.
At first, a feasibility study is carried out after which schedules, resource plans and, estimates for the next phase are developed. The feasibility study is an evaluation and analysis of the potential of a proposed project to support the process of decision making. It outlines and analyses alternatives or methods of achieving the desired outcome. The feasibility study helps to narrow the scope of the project to identify the best scenario. A feasibility report is generated following which Post Feasibility Review is performed.
The purpose of a feasibility assessment is to determine whether the engineer's project can proceed into the design phase. This is based on two criteria: the project needs to be based on an achievable idea, and it needs to be within cost constraints. It is important to have engineers with experience and good judgment to be involved in this portion of the feasibility study.
Following Feasibility, a concept study (conceptualization, conceptual engineering) is performed. A concept study is the phase of project planning that includes producing ideas and taking into account the pros and cons of implementing those ideas. This stage of a project is done to minimize the likelihood of error, manage costs, assess risks, and evaluate the potential success of the intended project.
Once an engineering issue is defined, solutions must be identified. These solutions can be found by using ideation, the mental process by which ideas are generated. The following are the most widely used techniques:
- trigger word - a word or phrase associated with the issue at hand is stated, and subsequent words and phrases are evoked.
- morphological chart - independent design characteristics are listed in a chart, and different engineering solutions are proposed for each solution. Normally, a preliminary sketch and short report accompany the morphological chart.
- synectics - the engineer imagines him or herself as the item and asks, "What would I do if I were the system?" This unconventional method of thinking may find a solution to the problem at hand. The vital aspects of the conceptualization step is synthesis. Synthesis is the process of taking the element of the concept and arranging them in the proper way. Synthesis creative process is present in every design.
- brainstorming - this popular method involves thinking of different ideas, typically as part of a small group, and adopting these ideas in some form as a solution to the problem
Establishing design requirements is one of the most important elements in the design process, and this task is normally performed at the same time as the feasibility analysis. The design requirements control the design of the project throughout the engineering design process. Some design requirements include hardware and software parameters, maintainability, availability, and testability.
The preliminary design, or high-level design (also called FEED), bridges the gap between the design concept and the detailed design phase. In this task, the overall system configuration is defined, and schematics, diagrams, and layouts of the project will provide early project configuration. During detailed design and optimization, the parameters of the part being created will change, but the preliminary design focuses on creating the general framework to build the project on.
Following FEED is the Detailed Design (Detailed Engineering) phase which may consist of procurement as well. This phase builds on the already developed FEED, aiming to further elaborate each aspect of the project by complete description through solid modeling, drawings as well as specifications.
Some of the said specifications include:
- Operating parameters
- Operating and nonoperating environmental stimuli
- Test requirements
- External dimensions
- Maintenance and testability provisions
- Materials requirements
- Reliability requirements
- External surface treatment
- Design life
- Packaging requirements
- External marking
Computer-aided design (CAD) programs have made the detailed design phase more efficient. This is because a CAD program can provide optimization, where it can reduce volume without hindering the part's quality. It can also calculate stress and displacement using the finite element method to determine stresses throughout the part. It is the engineer's responsibility to determine whether these stresses and displacements are allowable, so the part is safe.
Production planning and tool design
The production planning and tool design consists in planning how to mass-produce the project and which tools should be used in the manufacturing of the part. Tasks to complete in this step include selecting the material, selection of the production processes, determination of the sequence of operations, and selection of tools, such as jigs, fixtures, and tooling. This task also involves testing a working prototype to ensure the created part meets qualification standards.
With the completion of qualification testing and prototype testing, the engineering design process is finalized. The part must now be manufactured, and the machines must be inspected regularly to make sure that they do not break down and slow production.
Comparison with the Scientific Method
The engineering design process bears some similarity to the scientific method.  Both processes begin with existing knowledge, and gradually become more specific in the search for knowledge or a solution.
- Applied science
- Axiomatic product development lifecycle (APDL)
- Design engineer
- Design review
- Design science
- Engineering analysis
- Engineering design management
- Ideal final result
- Interaction design
- New product development
- Software development process
- Systems engineering process
- Traditional engineering
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- A.Eide, R.Jenison, L.Mashaw, L.Northup. Engineering: Fundamentals and Problem Solving. New York City: McGraw-Hill Companies Inc.,2002
- Ralph, P., and Wand, Y. A Proposal for a Formal Definition of the Design Concept. In, Lyytinen, K., Loucopoulos, P., Mylopoulos, J., and Robinson, W., (eds.), Design Requirements Engineering: A Ten-Year Perspective: Springer-Verlag, 2009, pp. 103-136.
- Widas, P. (1997, April 9). Introduction to finite element analysis. Retrieved from http://www.sv.vt.edu/classes/MSE2094_NoteBook/97ClassProj/num/widas/history.html
- Dieter, George; Schmidt, Linda (2007). Engineering Design. McGraw-Hill. p. 9. ISBN 978-0-07-283703-2.
- "Criteria for accrediting engineering programs, Engineering accrediting commission" (PDF). ABET.
- Ullman, David G. (2009) The Mechanical Design Process, Mc Graw Hill, 4th edition, ISBN 978-0072975741
- Eggert, Rudolph J. (2010) Engineering Design, Second Edition, High Peak Press, Meridian, Idaho, ISBN 978-0131433588