Chapter 3

Dr. Bahaa Al-Sheikh & Eng. Mohammed Al-Sumady

Intoduction to Engineering

Introduction to Engineering Design

Introduction to Engineering Design

Engineers, regardless of their backgrounds, follow certain steps when designing the products and services we use in our every day lives.

OutlineOutline

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 out

• Introduce important design factors such as Teamwork Project scheduling Material selection Economic consideration Engineering standards and codes

• Present cases studies in civil, 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

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

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 informationSearch 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

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

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 : 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 (متحمس )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 (عقبات).

• 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 membersDemonstrate 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

• 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

Questions?