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This presentation provides an overview of the theory of engineering design, including concepts, definitions, and types of design activities. Presented by Mr. Jeff Taylor, with respect to Dr. Abdulkadir Erden.
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THEORY of ENGINEERING DESIGN ISR MOONBUGGY An abridged/modified presentation by Mr. Jeff Taylor with great respects to the author Dr.Abdulkadir Erden, Atılım University, İncek, Ankara
Engineering ... is defined as an activity of overcoming difficulties for practical applications of concepts that are proved to be true theoretically. This activity is composed of mental activities, paperwork, human power and machine power.
Engineering ... is defined as an activity of overcoming difficulties for practical applications of concepts that are proved to be true theoretically. This activity is composed ofmental activities, paperwork, human powerandmachine power.
Remember these figures... NEED PEOPLE, SOCIETY, AND NATURE ENGINEERING PROCESS PRODUCT
Design Activity ... is defined, in general, as the planning and realization of a creative strategy to accomplish a physical, mental, moral or artistic task or to satisfy a real need.
Design Activity ... is defined, in general, as the planning and realization of a creative strategy to accomplish a physical, mental, moral or artistic task or tosatisfy a real need. This is engineering!..
Purpose of Design The purpose of design is defined [Mostow, 1985] as the construction of a structure (artifact) description that; • Satisfies a given (probably informal) functional specification, • Conforms to the limitations of the target medium, • Meets implicit or explicit requirements on performance (time, space, power, cost etc.) and structure (style, simplicity etc.), • Satisfies restrictions on the design process itself.
Design activities Design activities include • Creativity, • Decision-making, • Modeling.
Engineering and design activities are blended in Engineering Design
T. T. Woodson An iterative decision making activity to produce the plans by which resources are converted: preferably optimally, into systems or devices to meet human needs.
J. P. Vidosic The process that uses engineering tools-mathematics, graphics, language-and scientific principles to evolve a plan, which when fully carried out will satisfy a human need.
G. B. R. Fielden The use of scientific principles, technical information and imagination in the definition of a mechanical structure, machine or system to perform pre-specified functions with the maximum economy and efficiency.
M. Asimow A purposeful activity directed toward the goal of fulfilling human needs, particularly those which can be met by the technological factors of our culture.
C. Ruiz and F. Koenigsberger The complete intellectual process from the conception of an idea based on inspiration, knowledge and experience to its final technical and commercial realization.
J. R. Dixon Science-based problem solving with social-human awareness, ... a high level intellectual activity.
Pahl and Beitz, 1988 • Original designthat involves elaborating an original solution principle for a system with the same task, a similar task or a new task. This may be the case of using a four-bar mechanism in the development of a walking machine. • Adaptive design, which involves adapting a known solution principle to a changing task. Example: Design of a new gearbox, based on the known gear trains. • Variant design, which involves varying the size and/or arrangement of certain aspects of the chosen system, while the function and solution of the system remain, unchanged. Example: Belt Conveyor design; Size of drum and belt width can be computed for a given loading with no change on the design configuration.
Dieter, 1991 • One-of-a-kind design; Design of special purpose machines, Prototype machines, • Design for mass production; Design of washing machine, • Large, expensive system design; Design of a production line, • Design to code; Shaft design, Boiler design.
Ullman, 1992 • Selection designinvolves choosing one item from a list of similar items; Selection of bearing for a shaft. • Configuration designin which all the components have been designed and the problem is how to assemble them into the complete product; Plant design, Conveyor layout design • Parametric designinvolves finding values for the variables or parameters that characterize the object being studied; Conveyor design, Crane design. • Original designis the development of a process, component or assembly not previously existing; Design of a machine with a specific purpose. • Others (such as redesign, routine design)
DEFINITIONS FOR MECHANICAL ENGINEERING DESIGN OR MACHINE DESIGN
MachineDesign ... is described as a creative thinking, planning and synthesis supported by analyses in order to produce a machine or system that will accomplish a predefined physical work. Besides, having the properties of the general design concept, an important additional characteristic of the machine design therefore is that, the artifact to be designed should have a certain functionality in terms of physical work.
Machine Design ... is defined as the transformation of parameters influencing a physical process into concrete machine components,
R. C. Johnson The process of creating and selecting configurations, shapes, materials, and dimensions for something which is physical in nature.
W. Rodenacker The transformation of the parameters influencing physical process into concrete machine components.
P. Orlov • To abstain from blindly copying the existing prototypes and to design meaningfully, selecting from the entire store of the design solutions offered by the present day mechanical engineering the ones that are most suitable under given conditions. • To be able to combine various solutions and find new, better ones. • To continually improve the machines characteristics and to contribute to the progress in the given branch of mechanical engineering. • To follow the dynamic development of the industry and devise versatile machines of long life amenable to further modernization and capable of meeting the every growing demands of the national economy without running the risks of obsolescent for a long time to came.
J. P. Vidosic • The formulation of a plan for a mechanism or device capable of transmitting forces and motions, and doing work or accomplishing a specific function that must be done to satisfy a human need as economically as possible. • The formulation of plans to satisfy human needs using the disciplines-engineering, sciences, techniques, and other mental processes-that are studied by mechanical engineers.
E. Parr The application of many of the principles of science and technology in the creation of a product and the consideration of the various factors that effect its production and use.
MACHINE DESIGN = MACHINE + ENGINEERING + DESIGN
Design activities Design activities include • Creativity, • Decision-making, • Modeling.
Engineering creativity is a process in which a set of machine components is selected to perform a predetermined function. It is mainly a mental activity; assistance by computer technology is suggested. Designer's experience is also a determining factor.
Creativity Among the many factors which effect creativity in design are; designer’s experience, designer’s ability, economic factors, and designer’s own preference.
A product should be designed to function under all of the possible severe environmental conditions.
Remember • The stage and level of industrialization of the society is a factor in design, • The social traditions cannot be overcome easily, • Sophistication and complexity of the design product is to be determined by the user, • Economical conditions, • Geographical and climatic conditions.
Limitations of Design • Design should not violate scientific rules, • Design should be economical, • Design should be compatible to psychology and ergonomics, • Design must satisfy requirements stated in standards, laws, regulations, • Level of education and capabilities of the user, • Production facilities.
Philosophy of Design Design Process Scientific Principles and Technology Evaluation Design Information Feedback Work Product
to reach a perfect level ... 100 % Perfection Time / Effort Improvement of Level of Design with Time / Effort
