04.engineeringdesign

EC180 Engineering PracticeEngineering Design

Chulantha Kulasekere

Department of Electronic and Telecommunication EngineeringUniversity of Moratuwa

[email protected]

February 1, 2013

ECK/2013 (UoM) EC180 February 1, 2013 1 / 52

Difference Engineering Design and Engineering Science

Engineering Science Problem

Problem statement is compact and well-posed

Problem has a readily identifiable closure

Solution is unique and compact

Problem uses specialized knowledge

Engineering Design Problem

Problem statement is incomplete, ambiguous, and self-contradictory

Problem does not have a readily identifiable closure

Solutions are neither unique nor compact

Problem requires integration of knowledge from many fields


A Typical Engineering Science Problem Statement

A simply supported steel beam with a 3¨ diameter circularcross-section is loaded as shown.

Determine the maximum stress and deflection.


Another Engineering Science Problem Statement

How much current is flowing through the circuit 0.1 sec after theswitch is closed?


A Typical Engineering Design Problem Statement

Design a system for lifting and moving loads of up to 5000 lb in amanufacturing facility .

The facility has an unobstructed span of 50 ft.

The lifting system should be inexpensive and satisfy all relevant safetystandards.


Summary


ABET Definition of Design

Engineering design is the process of devising a system, component, orprocess to meet desired needs.It is a decision-making process (often iterative), in which the basicsciences and mathematics, and engineering sciences are applied toconvert resources optimally to meet a stated objective.Among the fundamental elements of the design process are theestablishment of objectives and criteria, synthesis, analysis,construction, testing, and evaluation.The engineering design component of a curriculum must include:development of student creativity, use of open-ended problems,development and use of modern design theory and methodology,formulation of design problem statements and specifications,consideration of alternative solutions, feasibility considerations,production processes, concurrent engineering design, and detailedsystem descriptions.Further, it is essential to include a variety of realistic constraints, suchas economic factors, safety, reliability, aesthetics, ethics, and socialimpact.


The DesignsJames Watts Steam Engine


The DesignsHenry Fords Motor Car


The DesignsSony Walkman


The DesignsPhilips -CD Player


The DesignsTank Sorowwa (Maduru Oya where Old and the New Met)


The DesignsBiso Kotuwa (A Sri Lankan Invention to reduce water pressure)


The DesignsThe Toilet (We were the first and not the French)


The DesignsFor discussion

How does the anti lock braking system work?

Explain the shape of an aircraft wing

Why is a differential needed?

What is the use of the independent suspension system in a car?

Explain the fabrication of the bullet proof vest

Why do cement bricks have holes in the middle?

How does a thermos flask work?

How does a touch screen work?

How do you take a picture with a camera?


Our Design History in the Recent Past

Heavy dependence on foreign technology

Heavy dependence on imported machinery

Heavy dependence on imported consumer products

No clear support from state

Why?

Local inventors were not supported by Colonial Rulers

No local development in-line with technological development tookplace during last 200 years

No significant contribution from the educated sector to improve thetechnology generation in Sri Lanka


Characteristics of a Design Engineer

ability to identify problems

ability to simplify problems

creative skills

sound technical knowledge

sense of urgency

analytical skills

sound judgment

decisiveness

open mindedness

ability to communicate

negotiating skills

supervisory skills.


Characteristics of a Design Engineer


Why Engineering Design is Important


Thinking Outside the BOXConnect the dots using 4 straight lines without lifting the pen


Thinking Outside the BOXNow connect the dots using 3 straight lines without lifting the pen


Thinking Outside the BOX4 lines


Thinking Outside the BOX3 lines


Some Software Tools used in Engineering Design

Project management tools (eg. Planner, MS Project)

Mind mapping tool (eg. Freemind, MindMeister, XMind)

Circuit design EDA (eg. OrCAD, Altium Designer, Proteus)

Solid Modeling (eg. SolidWorks, Medusa, FreeCAD, Pro Engineer)


Ten Step Model of the Design Process

1. Recognizing the need

2. Defining the problem

3. Planning the project

4. Gathering information

5. Conceptualizing alternative approaches

6. Evaluating the alternatives

7. Selecting the preferred alternative

8. Communicating the design

9. Implementing the preferred design

10. Evaluating the design


Step 1: Recognizing the Need

Communicate with the client (communication is the key)

Identifying the client needs against wants(customer requirements matrix.pdf)

A requirement is something the product should do/produce or aquality that it must have.

A customer requirements matrix can be filled if necessary.


Step 1: Recognizing the NeedDifferent Perspectives on Requirements


Step 1: Recognizing the NeedA typical example1

Sandra: “Jane, we need you to design a stronger bumper for our newpassenger car.”

Jane: “Why do we need a stronger bumper?”

Sandra: “Well, our current bumper gets easily damaged in low-speedcollisions, such as those that occur in parking lots.”

Jane: “Well, a stronger bumper may be the way to go, but theremay be better approaches. For example, what about a moreflexible bumper that absorbs the impact but then returns toits original shape?”

Sandra: “I never thought of that. I guess I was jumping toconclusions. Let’s restate the need as “there is too muchdamage to bumpers in low-speed collisions.” That shouldgive you more flexibility in exploring alternative designapproaches.”

1Tapping rubber, Writing on the MoonECK/2013 (UoM) EC180 February 1, 2013 28 / 52

Step 2: Defining the Problem

Goal

Objective

Constraints

Use of design Notebooks

Use of Mind Map tools to define the problem

Describe the problem by writing a problem statement. Your problemstatement must answer three questions:

What is the problem or need?Who has the problem or need?Why is it important to solve?

You can elaborate these ideas and gather information later


Design NotebooksPart of Leonardo daVinci’s notebook


Design NotebooksPart of Thomas Edision´s notebook


Design Notebooks


Step 3: Planning the Project

Using a tool to develop a Gantt Chart

Identifying the milestones and the costs involved.


Step 4: Gathering Information

Information sources to do a background research

Verify the accuracy

Organize and categorize the collected information

To make a background research plan, a road map of the researchquestions you need to answer:

Identify questions to ask about your target user or customer.Identify questions to ask about the products that already exist to solvethe problem you defined or a problem that is very similar.Plan to research how your product will work and how to make it.Use this Background Research Plan Worksheet to help you developyour own plan.


Step 5: Conceptualizing Alternative Approaches

Create design options (deal with objectives and constraints)

Concurrent engineering: which is sometimes called SimultaneousEngineering or Integrated Product Development (IPD), is a workmethodology based on the parallelization of tasks (i.e. performingtasks concurrently). It refers to an approach used in productdevelopment in which functions of design engineering, manufacturingengineering and other functions are integrated to reduce the elapsedtime required to bring a new product to the market.

Totally different approaches should be analyzed and pruned (eg.AnalyzeaPhysicalProduct.pdf)

The alternatives can be based on new ideas, examining existingsolutions to come up with better designs or based on creating andusing analogies (applying design methods applied to other artifacts).All of these will enrich the creative process.


Brainstorming as a Tool for Idea Generation

Composition:

Small team (5 to 10 members allowing individual ideas not to behidden)Diverse team: Select team members from different backgrounds.people with little and more experience

Logistics

Short meetings: brainstorming should be less than an hourRecord meetings: Identify a person to record the ideas on a board etc

Meeting protocol:

Group members should be considered equal: no hierarchyNonjudgmental: nothing is stupidQuantity over qualityBuild ideas: create new ideas by combining and building other ideas


Methods for Generating New Ideas

Checklist: Is a tabulation of ways that an objective can be achieved.

Attribute Listing: table of attributes of the device considered and thepossible values or solutions for each attribute. Attribute values can becombined in different ways to generate new ideas as well.

Morphological analysis: All the permutations of the attribute listing iscalled a morphological analysis.

Ideation

This creative process of developing multiple ideas to solve a single problemis called ideation.


Example of Generating Alternatives via New IdeaGeneration (1)


Example of Generating Alternatives via New IdeaGeneration (2)


Step 6/7: Evaluating/Selecting the Alternatives

Determine the effects and impact of each alternative

Use an objective evaluation methods (using formula, probability, orscience principle)

The Universal Design Criteria can also be used: Elegance,Robustness, Aesthetics, Cost, Resources, Time, Skill required, Safety.

Note that alternatives should be compared across a common set ofcriteria

Collect critiques via a decision matrix eg. DecisionMatrix.pdf

The answer to the above lies on the different feasibilities learnedbefore: Technical, Economic, Fiscal, Social/political/environmental.


Universal Design CriteriaElegance. An elegant design solution is simple, clever, or ingenious. Itmight have fewer parts to wear out or fail. It might combine solutionsfrom different areas in an inventive way not seen before. All gooddesigners strive for elegance in their designs.Robustness. A robust design is unlikely to fail, even when used inconditions more severe than it was designed for. It is sturdy orresilient, perhaps bending, but not breaking in hard use.Aesthetics. If everything else is equal, people prefer a solution that istasteful and pleasing to look at.Cost. What will it cost? Can the target user afford the solution? Doyou have enough money to build your prototype?Resources. Do you have all the materials and equipment you need foryour engineering project, or will you be able to obtain them quicklyand at a very low cost?Time. Do you have enough time to complete your design and make itbefore the due date? Allow time for doing additional research andfixing problems. It is very rare for everything to work correctly the firsttime.Skill Required. Do you have the skills to build and implement yoursolution, or can you learn them in the time available?Safety. Is your solution safe to build, use, store, and dispose of?


The Funnel


Example Analysis

Design of a portable wheelchair ramp.

Requirements: Meet the disable people act, The ramp must beadjustable to slopes between 1:20 and 1:12, have a minimum width of36 inches., ramp must be inexpensive, should bewheelchair-transportable.

Lets say the brainstorming activity yielded: an inflatable ramp, afoldable stainless steel ramp, fiberglass ramp

In a case such as this the analysis might consist of the followingquestions:

Can the ramp be made adjustable to slopes between the values given?Can the ramp be made with a width of at least 36 inches?Can the ramp with the above specifications bewheelchair-transportable?What is the cost of the ramp with all of the above characteristics?

Use the techniques learned to suggest an analysis.


Step 8: Communicating the Design

Use of language to bridge the gap between the ´design swamp´ to´land of the client´

Documentation methods which have to be followed.

Balance between the technical content and the marketing content tomeet the needs of the client.


What issues do you see with the lack of communicationwithin the design groups?


Design Innovation Strategies

Concurrent engineering: Concurrent engineering is a workmethodology based on the parallelization of tasks (i.e. performingtasks concurrently). It refers to an approach used in productdevelopment in which functions of design engineering, manufacturingengineering and other functions are integrated to reduce the elapsedtime required to bring a new product to the market.

Re-engineering (redesign): refers to a fundamental rethinking andradical redesign of a system.

Reverse Engineering: refers to the process of taking apart an object orsystem to see how it works and design based on your findings.

Failures are the pillars of success

A glue that did not stick well enough was nearly abandoned after a lot ofresearch but became the solution to 3M post-it notes which took the worldby storm.


Mode refined way of looking at Design StrategiesTop-Down

Also called ¨functional decomposition¨

implementation details considered only at the lowest level

top-down design, is not so clean and linear in practice

Often implementation-level commitments are made at high levels inthe design process


Mode refined way of looking at Design StrategiesCase Based

Research a specific, similar design case study

Model your process on that


Mode refined way of looking at Design StrategiesIncremental Redesign

Find an existing design and ¨unravel¨ the design from the bottom up

Modify as required

Detailed and least global aspects of the design are explored andredesigned, if necessary, first


Mode refined way of looking at Design StrategiesIncremental Redesign

An iterative top-down approach

First a rough, approximate and general design is completed

Then we do it finer, more exact and more specific

This process continues iteratively until the complete detail design indone


Mode refined way of looking at Design StrategiesBottom-up Design

Opposite of top-down

Start at the bottom with detail design

To do this, you must have some idea of where you are going. So,often this becomes a Hybrid Design


Mode refined way of looking at Design StrategiesHybrid Design

Combines aspects of both top down and bottom up

More practical design approach then pure top down

Start with a top-down approach, but have feedback from the bottom


Mode refined way of looking at Design StrategiesExplorer Method

Typically used for new design ideas or research

It is useful in initial design and specification stages, and is often usedwhen in ´unfamiliar territory´


Example Exercises

5E method of addressing the supermarket organizer

Building a single heat element coffee maker(http://www.engineerguy.com/videos/video-coffee-maker.htm)


04.engineeringdesign

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