This will help engineering students

1. Engineering Design
Chapter 1
© 2021 McGraw Hill. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or
further distribution permitted without the prior written consent of McGraw Hill.

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1.1 Introduction
What is design?

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What is design?
• “To fashion after a plan!”
• To design is:
“To design is to pull together something new or to
arrange existing things in a new way to satisfy a
recognized need of society.”
“Design establishes and defines solutions to and
pertinent structures for problems not solved before, or
new solutions to problems which have previously been
solved in a different way.”

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1.2 Engineering Design Process
Why is engineering design process needed?

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Importance of the Engineering Design
Process
• Decisions made in the design process cost very little
in terms of the overall product cost but have a major
effect on the cost of the product.
• You cannot compensate in manufacturing for defects
introduced in the design phase.
• The design process should be conducted so as to
develop quality, cost-competitive products in the
shortest time possible.

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Product Cost Commitment during Phases of
the Design Process
Adapted from D. Ullman, The Mechanical Design Process, 4th ed., McGraw-Hill, New York,2010.
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Types of Designs
• Original Design: Innovative design.
• Adaptive Design.
• Redesign: Variant design.
• Selection design.

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Original Design/ Innovative Design
• This form of design is at the top of the hierarchy. It
employs an original, innovative concept to achieve a
need.
• A truly original design involves invention.

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Adaptive Design
• This form of design occurs when the design team
adapts a known solution to satisfy a different need to
produce a novel application.

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Redesign*
• Engineering design is often employed to improve an
existing design.
• To
• Reduce cost of manufacturing
• Replace a failing component
• Redesign is accomplished without any change in the
working principle or concept of the original design.

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Selection Design
• Design task consists of selecting the components
with the needed performance, quality, and cost from
the catalogs of potential vendors.

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1.3 Ways to Think about the
Engineering Design Process
What do we mean by “designing a system”?

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Simplified Iteration Model
Adapted from M. Asimow, Introduction to Design, Prentice-Hall, Englewood Cliffs, NJ, 1962.
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Design Method versus Scientific Method
Adapted from P. H. Hill, The Science of Engineering Design, Holt, Rinehart and Winston, New York 1970.
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A Problem-Solving Methodology
• Definition of the problem.
• Gathering of information.
• Generation of alternative solutions.
• Evaluation of alternatives and decision making.
• Communication of the results.

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How the Design Depends on How the
Problem Is Defined
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Design Paradox between Design Knowledge
and Design Freedom
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1.4 Description of Design Process
What are the steps of Design Process?

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Design Process Phases

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Phase I. Conceptual Design
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Phase II. Embodiment Design
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Phase III. Detail Design

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Engineering Design Process
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Product Design Specification 1
Product Identification
• Product name (# of models or
different versions, related in-
house product families).
• Basic functions of the product.
• Special features of the product.
• Key performance targets (power
output, efficiency, accuracy).
• Service environment (use
conditions, storage,
transportation, use and
predictable misuse).
• User training required.
Market Identification
• Description of target market and
its size.
• Anticipated market demand
(units per year)
• Competing products.
• Branding strategy (trademark,
logo, brand name)
What is the need for a new (or
redesigned) product? How much
competition exists for the new
product? What are the relationships
to existing products?

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Product Design Specification 2
Key Project Deadlines
• Time to complete project.
• Fixed project deadlines (for example, review dates)
Physical Description
What is known (or has already been decided) about the physical
requirements for the new product?
• Design variable values that are known or fixed prior to the conceptual
design process (for example, external dimensions)
• Constraints that determine known boundaries on some design
variables (for example, upper limit on acceptable weight)

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Product Design Specification 3
Financial Requirements
What are the assumptions of the firm about the economics of the
product and its development?
What are the corporate criteria on profitability?
• Pricing policy over life cycle (target manufacturing cost, price,
estimated retail price, discounts)
• Warranty policy.
• Expected financial performance or rate of return on investment.
• Level of capital investment required.

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Product Design Specification 4
Life Cycle Targets
What targets should be set for the performance of the product over
time? (This will relate to the product’s competition.)
What are the most up-to-date recycling policies of the corporation and
how can this product’s design reflect those policies?
• Useful life and shelf life.
• Cost of installation and operation (energy costs, crew size, etc.)
• Maintenance schedule and location (user-performed or service
centered)
• Reliability (mean time to failure): Identify critical parts and special
reliability targets for them
• End-of-life strategy (% and type of recyclable components,
remanufacture of the product, company take back, upgrade policy)

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Product Design Specification 5
Social, Political, and Legal Requirements
Are there government agencies, societies, or regulation boards that
control the markets in which this product is to be launched?
Are there opportunities to patent the product or some of its
subsystems?
• Safety and environmental regulations. Applicable government
regulations for all intended markets.
• Standards. Pertinent product standards that may be applicable
(Underwriters Laboratories, OSHA).
• Safety and product liability. Predictable unintended uses for the
product, safety label guidelines, applicable company safety
standards.
• Intellectual property. Patents related to product. Licensing strategy
for critical pieces of technology.

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Product Design Specification 6
Manufacturing Specifications
Which parts or systems will be manufactured in-house?
• Manufacturing requirements. Processes and capacity necessary to
manufacture final product.
• Suppliers. Identify key suppliers and procurement strategy for
purchased parts.

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Idea to product realization
Invention Date of Idea Technical
realization
Delay(years)
Power generator 1820 1849 29
Electricity production 1708 1800 92
Locomotives 1769 1824 55
Photography 1727 1838 111
Nylon 1927 1938 11
Telephone 1854 1881 27
Gasoline motor 1860 1886 26
Jet engine 1928 1941 13
Lead battery 1820 1886 47
Safety matches 1805 1866 61
Aluminum 1827 1887 60
Refrigeration 1873 1895 23
Source: Make andTest Projects in Engineering Design Creativity, Engagement and Learning by Andrew Samuel

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1.5 Consideration of a Good Design
What are the various considerations of a good design?

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Considerations of Good Design
1. Achievement of Performance Requirements
2. Life-Cycle Issues
3. Social and Regulatory Issues

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Achievement of Performance Requirements
• A major characteristic of a design is its function.
• Performance Requirements:
Primary Performance Requirements
Complementary Performance Requirements
• Part (Component): A single piece requiring no
assembly.
• Assembly: When two or more parts are joined.
• Subassemblies: Smaller assemblies which compose
larger assemblies.

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Total Materials Life Cycle
Reproduced from “Materials and Man’s Needs,” National Academy of Sciences, Washington, D.C., 1974.
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Regulatory and Social Issues
• The code of ethics of all professional engineering
societies require the engineer to protect public
health and safety.
Example of Standards and Codes:
ASME: American Society of Mechanical Engineers
ASTM: American Society for Testing and Materials
OSHA: Occupational Safety and Health Administration
CPSC: Consumer Product Safety Commission
EPA: Environmental Protection Agency
DHS: Department of Homeland Security

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1.6 Computer-Aided Engineering
What are the changes that plentiful computing has produced?

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Computer-Aided Engineering (CAE)
• The advent of plentiful computing has produced a major
change in the way engineering design is practiced.
Advantages of Computer-Aided Engineering:
Automated engineering drawing in two dimensions
Three dimensional modelling
Finite Element Modeling (FEM)
Rapid prototyping
Design optimization
Computer-Aided Design (CAD)
Computer-Aided Manufacturing (CAM)

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FEM / Finite Element Analysis (FEA)
Images from COMSOL Finite Element Mesh Refinement

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1.7 Designing to Codes and
Standards
What are the codes and standards?

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Designing to Codes and Standards
• A code is a collection of laws and rules that assists a
government agency in meeting its obligation to protect the
general welfare by preventing damage to property or injury or
loss of life to persons.
• A standard is a generally agreed-upon set of procedures,
criteria, dimensions, materials, or parts.
Chief Aspects of Designing to Codes and Standards:
In
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e
a
s
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• Efficiency.
• Safety.
• Interchangeability.
• Compatibility.

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Two Broad Forms of Codes
Performance Codes Prescriptive Codes
• Performance Codes are stated in terms of the specific
requirement that is expected to be achieved.
• Prescriptive(specification) Codes state the
requirements in terms of specific details and leave no
discretion to the designer.

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1.8 Design Review
What is design review?

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Design Review
A design review is a retrospective study of the design up to that point in
time.
The essence of the technical review of the design is to compare the
findings against the detailed Product Design Specification (PDS).
The PDS is a detailed document that describes what the design must be
in terms of:
• Performance requirements.
• Environment in which it must operate.
• Product life.
• Quality.
• Reliability.
• Cost.
• Host of other design requirements.

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Redesign
Two categories of redesigns:
• Fixes.
• Updates.
A fix is a design modification that is required due to
less than acceptable performance once the product
has been introduced into the marketplace.
Updates are usually planned as part of the product’s
life cycle before the product is introduced to the
market.

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An Examples of Design Update
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1.9 Societal Considerations in
Engineering Design
What are the effects of engineering design on society?

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Societal Considerations in Engineering
Design
ABET Code of Ethics:
“Engineers shall hold paramount the safety, health, and welfare of the
public in the performance of their profession.”
Some influences on the practice of engineering design due to
increased societal awareness of technology:
• Greater influence of lawyers on engineering decisions.
• More time spent in planning and predicting.
• Emphasis on “defensive research and development”
• More effort expended in research, development, and
engineering in environmental control and safety.

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Keys Roles of Government in Interacting
with Technology
• As a stimulus to free enterprise through changes in
the tax system.
• By influencing interest rates and the supply of
venture capital through changes in fiscal policy to
control the growth of the economy.
• As a major customer for high technology, chiefly in
military, space, and energy systems.
• As a funding source (patron) for research and
development.
• As a regulator of technology.

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Things to consider
• Engineering design is only one aspect of design
• Mechanical design: mechanical engineering design
primarily deals with machinery that moves objects,
moves fluids, or transfers heat or energy.
• Industrial design : focuses on specification of the
form and features of an object in order to make
products effective, easy, appealing and safe to use.

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Things to consider
• Process design: Process design is focused on
activities instead of objects. The activity could be the
creation of a substance or material (chemical
process design, metallurgical process design)…
• Systems engineering: Involves the application
design principles to the integration and management
of complex systems.
• User interface (UI/UX) design: Focuses on the way
that people interact with technology.

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Things to consider
• Human factors and ergonomics design: Human
factors engineering solves design problems related
to the way that humans interact with objects and
systems.
• Design for X: Design for X refers to the focus on,
and optimization of, a particular trait, "X", during the
design process.
• Others to consider: Universal design, sustainable
design, social innovation, human-centered design.

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© 2021 McGraw Hill. All rights reserved. Authorized only for instructor use in the classroom. No reproduction or
further distribution permitted without the prior written consent of McGraw Hill.