Lecture 3
Dr. Khaled Bakro
Introduction to Engineering Design
Introduction to Engineering
and Profession Ethics

PART 1 – ENGINEERING ——
AN EXCITING PROFESSION
Engineers, regardless of their backgrounds, follow
certain steps when designing the products and
services we use in our every day lives.
3- Introduction to Engineering Design

Outline
Outline 1
In this chapter we will
• Introduce you to the engineering design
process.
• Discuss the basic steps that most engineers
follow when designing a product.
• Discuss the importance of considering
sustainability in design.

Outline
Outline 2out
• Introduce important design factors such as
 Teamwork
 Project scheduling
 Material selection
 Economic consideration
 Engineering standards and codes
• Present cases studies in mechanical/ electrical
engineering

objective
The main objective of this chapter is:
To introduce the steps engineers
follow to successfully design
products or provide services that we
use in our everyday lives.

What ıs Engineering Design?
 Engineering Design is a process of devising a
system, component, or process to meet a desired
need.
 It is a decision-making process, often iterative, in
which the basic sciences, mathematics, and
engineering sciences are applied to convert
resources to meet a stated objective.
 Structured problem-solving activity

The Engineering Design Process
Design Process – Basic Steps:
1. Recognizing the need for a product or a service
2. Problem definition and understanding
3. Research and preparation
4. Conceptualization
5. Synthesis
6. Evaluation
7. Optimization
8. Presentation

The Engineering Design Process
Design Process –Basic steps (other methodology) :

Design Process – Basic Steps
Design Process – Basic Steps
 Step 1 : Recognizing the need for a product or a service

Design Process – Basic Steps
Step 2: Problem definition and understanding
• This is the most important step in any design
process
• Before you move on to the next step
 Make sure you understand the problem
 Make sure that the problem is well defined
• Good problem solvers are those who first fully
understand what the problem is.

Design Process – Basic Steps
Step 3: Research and preparation (Project Panning)
• Collect useful information
 Search to determine if a product already
exists
 Perhaps you could adopt or modify
existing components
 Review and organize the information
collected in a suitable manner

Design Process – Basic Steps
Step 4: Conceptualization ( Brainstorming)
Generate ideas or concepts that could offer
reasonable solutions to your problem

Design Process – Basic Steps
Step 5: Synthesis
• At this point you begin to consider details
• Perform calculations, run computer models, narrow down
the type of materials to be used, size the components of the
system, and answer questions about how the product is
going to be fabricated
• Consult pertinent codes
and standards for
compliance

Design Process – Basic Steps
Step 6: Evaluation
• Analyze the problem in more detail
• Identify critical design parameters and consider their
influence in your final design
• Make sure that all calculations are performed correctly
• Best solution must be identified from alternatives
• Details of design must be worked out fully

Design Process – Basic Steps
Step 7: Optimization – minimization or
maximization
• Optimization is based on some particular criterion
such as cost, strength, size, weight, reliability, noise,
or performance.
• Optimizing individual components of an
engineering system does not necessarily lead to an
optimized system

Design Process – Basic Steps
An optimization procedure

Design Process – Basic Steps
Step 8: Presentation
• You need to communicate your solution to the
client, who may be your boss, another group within
your company, or an outside customer
• Engineers are required to give oral and written
progress reports on a regular basis to various
groups; consequently, presentation could well be an
integral part of many other design steps

Other Engineering Design
Considerations
• Engineering economics
• Material selection
• Teamwork
• Conflicts Resolution
• Project scheduling and task chart
• Evaluating alternatives
• Patent, trademark, and copyright
• Engineering standards and codes

Engineering Economics
• Economic factors always play important roles in
engineering design decision making
• Products that are too expensive cannot be sold at a
price that consumers can afford and still be
profitable to the company
• Products must be designed to provide services not
only to make our lives better but also to make good
profits for the manufacturer
More in
Chapter 20

Material Selection
• Selection of materials is an important design decision
• Examples of properties to consider when selecting
materials
 Density
 Ultimate strength
 Flexibility
 Machinability
 Durability
 Thermal expansion
 Electrical & thermal conductivity
 Resistance to corrosion

Material Properties
• Material properties depend on many factors
 How the material was processed
 Its age
 Its exact chemical composition
 Any nonhomogenity or defect within the material
• Material properties change with temperature and time
as the material ages
• In practice, you use property values provided by the
manufacturer for design; textbook values are typical
values

List of Some Material Properties
• Electrical resistivity : a measure of resistance of material to flow of electricity.
• Density : : how compact the material is for a given volume.
• Modulus of Elasticity : how easily material will stretch or shorten.
• Modulus of Rigidity : a measure of how easily a material can be twisted or
sheared.
• Modulus of resilience : a mechanical property of a material that shows how
effective the material is in absorbing mechanical energy without going
through any permanent damage.
• Modulus of toughness : a mechanical property of a material that indicates the
ability of the material to handle overloading before it fractures.
• Thermal expansion : the change in the length of a material that would occur if
the temperature of the material is changed.
• Thermal conductivity : how good the material is in transferring thermal
energy .
• Heat capacity : represents the amount of thermal energy required to
raise the temperature of one kilogram mass of a material by one
degree Celsius. Materials with large heat capacity values are good at
storing thermal energy

Material Properties (fluid properties)
• Viscosity : a measure of how easily the given fluid
can flow. The higher the viscosity value is, the more
resistance the fluid offers to flow.
• Vapor pressure : fluids with low vapor-pressure
values will not evaporate as quickly as those with
high values of vapor pressure.
• Bulk modulus of compressibility ‫الحجم‬ ‫معامل‬‫ل‬‫النضغاطية‬ :
represents how compressible the fluid is. How
easily can one reduce the volume of the fluid when
the fluid pressure is increased.

Teamwork
• Design team
a group of individuals with complementary
expertise, problem solving skills, and talent who are
working together to solve a problem or achieve a
common goal
• Employers are looking for individuals who not only
have a good grasp of engineering fundamentals but
who can also work well with others in a team
environment

Common Traits of Good Teams
Successful teams have the following components:
• The project that is assigned to a team must have
clear and realistic goals. These goals must be
understood and accepted by all members of the team.
• The team should be made up of individuals with
complementary expertise, problem solving skills,
background, and talent.
• The team must have a good leader.

Common Traits of Good Teams
• The team leadership and the environment
in which discussions take place should
promote openness, respect, and honesty.
• The team goals and needs should come
before individual goals and needs.

Secondary Roles of Good Team Members
• The Organizer – experienced and confident; trusted
by members of the team and serves as a coordinator
for the entire project
• The Creator – good at coming up with new ideas,
sharing them with other team members, and letting
the team develop the ideas further
• The Gatherer – enthusiastic and good at obtaining
things, looking for possibilities, and developing
contacts

Secondary Roles of Good Team Members
• The Motivator – energetic, confident, and outgoing;
good at finding ways around obstacles .
• The Evaluator – intelligent and capable of
understanding the complete scope of the project;
good at judging outcomes correctly
• The Team Worker – tries to get everyone to come
together, does not like friction or problems among
team members

Secondary Roles of Good Team Members
• The Solver – reliable and decisive and can turn
concepts into practical solution
• The Finisher – can be counted on to finish his or
her assigned task on time; detail oriented and may
worry about the team’s progress toward finishing
the assignment

Conflicts
When a group of people work together, conflicts
sometimes arise. Conflicts could be the result of
• Miscommunication
• Personality differences
• The way events and actions are interpreted by a
member of a team

Conflict Resolution
• Managing conflicts is an important part of a team
dynamic
• In managing conflicts, it is important to recognize
there are three types of people:
 Accommodating
 Compromising
 Collaborative

Conflict Resolution – Type of People
• Accommodating team members - avoid
conflicts
 Allow assertive individuals to dominate
 Making progress as a whole difficult
 Could lead to poor team decision

Conflict Resolution – Type of People
• Compromising team members
Demonstrate moderate level of
assertiveness and cooperation. By
compromising, the team may have sacrificed
the best solution for the sake of group unity

Conflict Resolution
• Collaborative Conflict Resolution Approach
 High level of assertiveness and cooperation by
the team
 No finger pointing
 Team proposes solutions
 Means of evaluation
 Combine solutions to reach an ideal solution

Project Scheduling and Task Chart
 A process that engineering managers use to ensure that a project is
completed on time and within the allocated budget

Evaluating Alternatives
• When a design is narrowed down to a
few workable concepts, evaluation of
these concepts is needed before detail
design is pursued
• Each design would have its own
evaluation criteria

An Example of evaluation worksheet

Sustainability in Design
Sustainability and sustainable engineering can be
defined as
“design and development that meets the needs of the
present without compromising the ability of future
generations to meet their own needs.”

Sustainability in Design
• Engineers contribute to both private and public
sectors of our society
• In private sector, they design and produce the goods
and services that we use in our daily lives to allow us
to enjoy a high standard of living
• In public sector, they support local, state, and federal
mission such as meeting our infrastructure needs,
energy and food security, and national defense

Sustainability in Design
• Increasingly, because of worldwide socioeconomic
trends, environmental concerns, and earth’s finite
resources, more is expected of engineers
• Future engineers are expected to design and provide
goods and services that increase the standard of living
and advance health care, while addressing serious
environmental and sustainability concerns
• In designing products and services, engineers must
consider the link among earth’s finite resources,
environmental, social, ethical, technical, and
economical factors

Summary
• You should know the basic design steps that all
engineers follow, regardless of their background, to
design products and services
• You should realize that economics plays an
important role in engineering decision making
• You should realize that the selection of material is
an important design decision
• You should be familiar with the common traits of
good teams

Case Study
42
Hyper Loop
Case study in mechanical/ electrical engineering

Sport Utility Vehicle (SUV)
Anti-Lock Braking System (ABS)
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Identification of Problem
• What is required?
• What must be done and
why?
• Scope of problem – define
problem boundaries.
• Example – Anti-lock Braking
System
– Is it possible to
successfully retrofit an
ABS developed for
compact cars to heavier,
sports utility vehicles?
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Research the Problem
• Can we decompose the problem
into easily managed subproblems?
• This step defines, for example;
– Literature review for similar
problems and solutions to those
problems.
– Relevant analytical and
modeling techniques.
– Testing requirements.
– Design constraints.
– Resource requirements and
allocation.
– Project schedule.
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Research – ABS Example
• Literature search; Internet search on
ABS.
• Constraints (example);
– Retain compact car ABS system
architecture.
– SUV ABS costs cannot exceed 110% of
current compact car ABS system cost.
– Time to market – 3 months.
– Performance criteria;
• SUV Total Time to Stop  15% increase over
compact car.
• SUV Wheel Lock Skid Time  10% increase
over compact car.
• Approach:
– Develop MATLAB model of ABS system.
– Parametric analysis using model.
– Modify system constants.
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Solve the Problem
• Develop alternatives. For
example;
– Hardware and software design
alternatives.
– List of independent variables to
vary in modeling or simulation.
• Modeling
– Conceptual models.
– Physical models and engineering
mockups.
– Graphical models.
– Mathematical models.
– Computer models.
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Decision Matrix
48
Alternative Solutions
Criteria
Ease of Ass
Score
Score
Score
Score
Functionality
Cost
Stability
Total Score
Weight
35%
25%
25%
15%
100%
1 2 3 4 5
140
4
5
125
6
150
7
105
520
5 6 8 8
8888
6 5 7 7
3 9 9 10
175
200
150
45
570
210
200
125
135
670
280
200
175
135
790
280
200
175
150
805

Solve the Problem
• Experimentation
– Computer simulation.
– Testing, for example;
• Ground tests.
• Flight testing.
• Synthesis
– Subproblem solutions are merged.
– E.g., manufacturing and
engineering resolving issues
associated with manufacturability.
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Solve Problem – ABS Example
• ABS hardware and system architecture fixed
with exception of interface to SUV.
• Control software can be modified.
• Matlab simulation.
• Skid pad testing to verify simulation results.
• Presentation of results to Product
Development Team.
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ABS Braking Simulation Model
51

Simulation Results
52
Vehicle Weight = 1600lbs
Hydraulic Lag – 0.01 sec

Simulation Results
53
Vehicle Weight = 2900 lbs
Hydraulic Lag – 0.01 sec

Simulation Results
54
0 2 4 6 8 10 12 14 16 18
0
10
20
30
40
50
60
70
80
Vehicle speed and wheel speed
Speed(rad/sec)
Time(secs)
Vehicle speed ( v
)
Wheel speed ( w
)
Vehicle Weight = 2900 lbs
Hydraulic Lag – 0.03 sec

Simulation Results
55
Vehicle Weight = 2900 lbs
Hydraulic Lag – 0.007 sec

Presentation
56
Baseline
Best Solution

Testing - ABS
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Presentation
58
15.40
15.60
15.80
16.00
16.20
16.40
16.60
0.007 0.01 0.03
TotalTimetoStop(sec)
Hydraulic System Time Constant (sec)
TTS vs. Hydraulic Time Constant
Is this relationship linear or
nonlinear?
Wt = 2900 lbs

Presentation
59
0.00
0.50
1.00
1.50
2.00
2.50
0.007 0.01 0.03
WheelLockSkidTime(sec)
Hydraulic System Time Constant (sec)
Wheel Lock Skid Time vs. Hydraulic Time Constant
Wt = 2900 lbs

Results
• Performance Criteria Satisfied.
• Total Time to Stop
– Required – 15% increase over compact car.
– Actual – 12.8% increase.
• Wheel Skid Lock Time
– Required – 10% increase over compact car.
– Actual – 0% increase over compact car.
• Time to market – 1.5 months for S/W revisions.
• Cost – Less than a 2% increase.
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