Lecture 3 - Design Matrices

SESG-2005

Engineering Design and Structural Analysis Methods

James Scanlan, Mohamed Torbati, and Hakki Eres18 February 2010

2

Design challenges of A380 team

Some results:

– Logistics: Timely arrival of very large parts through rivers, narrow roads and villages, etc.

– Large scale coordination issues between all partners, standards, units of measure, time scales, tolerances, etc.

– Lifting and precise assembly of large parts, assembly order

– Engine integration: Trent 900 (Rolls-Royce), GP7200 (GE, Pratt & Whitney)

– Scale of the assembly plant – custom built for A380

– Safety of workers

– Safety of the aircraft, proper testing procedures

Examples

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Examples

4

Examples

5

Examples

6

Examples

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Examples

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Design Matricesa. TRIZb. QFD

TRIZTeoriya Resheniya Izobretatelskikh Zadatch

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TRIZ

• Теория решения изобретательских задач (Teoriya Resheniya Izobretatelskikh Zadatch)

• Meaning

– The theory of solving inventor's problems

– The theory of inventor's problem solving

– The theory of inventive problem solving (TIPS)

• First developed by Genrich Saulovich Altshuller and his colleagues around 1946

12

History of TRIZ ‡

• Genrich Saulovich Altshuller

– Born in 1926 (Tashkent, Uzbekistan)

– Died in 1998 (Petrozavodsk, Karelia)

• Inventor since childhood: a boat with a jet engine, gun-thrower, spacesuit.

• 1946 Patent Officer in Russian Navy

• Discovered patterns in patents, published paper

• Arrested in 1950. Sent to Gulag. Released in 1954

• Analysed about 2,500,000 patents

• Identified what makes a successful patent

• 1956-1985 TRIZ formulated

‡http://www.altshuller.ru/biography/ (In Russian)

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Patent classifications of TRIZ ‡

• After devoting hundreds of person-years, the patents have been classified as the following:

1. Basic parametric advancement

2. Change or rearrangement in a configuration

3. Identifying conflicts and solving them with known physical principles

4. Identifying new principles

5. Identifying new product functions and solving them with known or new principles

Routine

design

Inventive

solutions

‡Product Design, Kevin Otto and Kristin Wood, 2001.

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Key discoveries of TRIZ ‡

• Some of the key observations relevant to product design include:

1. Evolution of products follows similar patterns, independent of the engineering discipline or product domain. These patterns can be used to predict the trends and direct the search for new concepts.

2. Conflicts are the key drivers for product invention.

3. The systematic application of physical effects aids invention.

4. Innovative patents (23% of total) used science/engineering theories outside their own domain.


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Generalised engineering parameters

• Total of 39 generalised engineering parameters for describing product metrics are identified.

• Examples:

– Velocity (#9)

– Force (#10)

– Temperature (#17)

– Power (#21)

– Energy loss (#22)

• Full list is available in Blackboard.

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Design principles to solve conflicts

• Total of 40 design principles are identified.

• Examples:

– Principle of removal (#2)

– Replacement of a mechanical system (#28)

– Using flexible or fine membranes (#30)

– The use of phase changes (#36)

• Full list is available in Blackboard.

Conflicting relationship matrix

• Actual matrix size: 39x39, available in Blackboard.

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Worsening Feature

Improving Feature

1 2 3 4 5 6 7 8 9 10

1 * -15 8

-29 17

-29 2

-2 8 8 10

29 34 38 34 40 28 15 38 18 37

2 - * -10 1

-35 30

-5 35

-8 10

29 35 13 2 14 2 19 35

38 15

- * -15 17

-7 17

-13 4 17 10

29 34 4 4 35 8 4

4 -35 28

- * -17 7

-35 8

- 28 1040 29 10 40 2 14

52 17

-14 15

- * -7 14

-29 30 19 30

29 4 18 4 17 4 4 34 35 2

6 -30 2

-26 7

- * - - -1 18

14 18 9 39 35 36

72 26

-1 7

-1 7

- * -29 4 15 35

29 40 4 35 4 17 38 34 36 37

8 -35 10

19 1435 8

- - - * -2 18

19 14 2 14 37

92 28

-13 14

-29 30

-7 29

- *13 28

13 38 8 34 34 15 19

108 1 18 13 17 19

28 1019 10 1 18 15 9 2 36 13 28

*37 18 1 28 9 36 15 36 37 12 37 18 37 15 12

List of design principles to

solve the engineering

conflict of 4 and 10

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Function analysis: Lens polishing

Problem: As lens is being polished, heat is generated. The heat causes optical properties to be degraded. Current cooling methods are ineffective because it is difficult to achieve uniform cooling at each abrasive particle.

System components:

– Lens

– Abrasive particles

– Abrasive particle binding agent

LENSABRASIVE

STICK

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Contradiction: Lens polishing

Thing I would like to improve:- SPEED

Thing that gets worse:- TEMPERATURE

Has anyone else had (and solved) a similar contradiction?

LENSABRASIVE

STICK

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TRIZ relationship matrix

... 16. Duration of action generalised by stationary object

17. Temperature

18. Brightness

...

...

8. Volume of stationary object

9. Velocity28 3036 2

10. Force

...

Improving

feature

Deteriorating

feature

Try the interactive TRIZ relationship matrix at

http://triz40.com/

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Design principles for our problem# Name Explanation Examples

28Replacement of a mechanical system

Replace a mechanical system by an optical, acoustical or olfactory (odour) system. Use an electrical, magnetic or electromagnetic field for interaction with the object. Replace fields: 1. Stationary fields with moving fields, 2. Fixed fields with those which change in time, 3. Random fields with structured fields. Use a field in conjunction with ferromagnetic particles.

To increase the bond between metal coating and a thermoplastic material, the process is carried out inside an electromagnetic field which applies force to the metal.

30Flexible membranes or thin film

Replace traditional constructions with those made from flexible membranes or thin film. Isolate an object from its environment using flexible membranes or thin film.

To prevent water evaporation from plant leaves, polyethylene spray was applied. After a while, the polyethylene hardened and plant growth improved, because polyethylene film passes oxygen better than water vapour.

36Phase transformation

Implement an effect developed during the phase transition of a substance. For instance, during the change of volume, liberation or absorption of heat.

To control the expansion of ribbed pipes, they are filled with water and cooled to a freezing temperature.

2 ExtractionExtract (remove or separate) a "disturbing" part or property from an object. Extract only the necessary part or property

To frighten birds away from the airport, use a tape recorder to reproduce the sound known to excite birds. (The sound is thus separated from the birds.)

Full list of design principles are available in Blackboard.

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Lens polishing: Example solution

• Use inventive design principle #36 „Phase transition‟ and embed abrasive particles in ice!

LENSABRASIVE

+ ICE

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TRIZ Inventive Principles Solution Guide

SpecificProblem

TRIZ GenericProblem

TRIZ GenericSolution

SpecificSolution

Step 1:

Define problem

in terms of generic

contradiction

parameters

Step 2:

Use contradiction

matrix to find relevant

inventive principles

Step 3:

Translate generic

inventive principles

into specific solution

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TRIZ Example: Iron‡

Function: Transfer force to clothing to aid in removing wrinkles.

Conflict:

– Heavy iron to remove wrinkles easier

– Reduce the force required by the user (ergonomics)


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TRIZ Example: Iron‡

• Generalised engineering parameters

– Improving parameter: Force (#10)

– Deteriorating parameter: Weight of moving object (#1)

• Generic relationship matrix suggests the following solutions

– 8, 1, 37, 18


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Group work

• You can work in teams of 5-6. Use the group exercise sheet and write down your names.

• Assume you are members of Bosch concept design team.

• Try to find specific design solutions to improve the wrinkle removing performance of your new iron design.

• The suggested inventive design solutions will be shown.

• You have 5 minutes starting now!

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Generic relationship matrix results# Name Explanation Examples

8 Counterweight

Compensate for the object's weight by joining with another object that has a lifting force. Compensate for the weight of an object by interaction with an environment providing aerodynamic or hydrodynamic forces.

* Boat with hydrofoils* A rear wing in racing cars which increases pressure from the car to the ground

1 SegmentationDivide an object into independent parts. Make an object sectional. Increase the degree of an object's segmentation.

* Sectional furniture, modular computer components, folding wooden ruler* Garden hoses can be joined together to form any length needed

37 Thermal expansionUse a material which expands or contracts with heat. Use various materials with different coefficients of heat expansion.

To control the opening of roof windows in a greenhouse, bimetallic plates are connected to the windows. A change in temperature bends the plates, causing the window to open or close.

18Mechanical vibration

Set an object into oscillation. If oscillation exists, increase its frequency, even as far as ultrasonic. Use the resonant frequency. Instead of mechanical vibrations, use piezovibrators. Use ultrasonic vibrations in conjunction with an electromagnetic field.

* To remove a cast from the body without injuring the skin, a conventional hand saw was replaced with a vibrating knife* Vibrate a casting mold while it is being filled to improve flow and structural properties

Full list of design principles are available in Blackboard.

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Specific design solutions

1. Use of levered counterweight (from #8 - Counterweight)

2. Foot-operated sandwich iron (from #1 - Segmentation)

3. Separate steam generator from the iron (from #1 - Segmentation)

4. Use water spray or steam to improve performance (from #37 – Thermal expansion)

QFDQuality Function Deployment

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What is QFD?

• QFD is a design methodology

– defines the customer‟s needs

– prioritise these needs

– translate the needs into engineering requirements

– establish targets for meeting engineering requirements

• A highly structured set of documentation.

• A way of ensuring that a design meets customer requirements.

Phase I: Product Planning

Phase II: Parts Deployment

Phase III: Process Planning

Phase IV: Production Planning

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QFD background

• Initially conceived and developed by Dr Yoji Akao, along with Dr Shigeru Mizuno.

• First application in the 1970‟s by Mitsubishi‟s Kobe Shipyard to manage design logistics for large complex ships.

• Currently used in a number of industries, including automotive, aerospace, and electronics.

Dr Yoji Akao

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Customer requirements

• For a successful design the customer requirements need to be understood.

• In order to determine priorities for a new design, a designer must

– find weakly satisfied customer needs

– understand the dependencies between customer requirements and actual design parameters

– determine which parameters affect to improve weak points of the design

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The House of Quality (HoQ)

Try the online tutorial at http://www.webducate.net/qfd/qfd.html

WHAT

Customer

Requirements

Im

portance

Rating

Relationship

Matrix

Custom

er

Targets a

nd

Rankings

HOW

Functional Requirements

TARGETS

How Much

Correlation

Matrix

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Simplified HoQ procedure‡

1. Identify all customers, both internal and external.

– Consumers, manufacturing team, regulators, marketing, distributors, sales

2. Determine the customers needs (WHATs in the HoQ)

– WHATs can be organised in primary, secondary, etc.

– List descriptions of needs (Use “easy”, “fast”, “light-weight”, etc.)


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Simplified HoQ procedure‡ (cont.)

3. Determine the relative importance of the customer needs

– Use a scale of 1-5 or 0%-100%

4. Translate customer needs into measurable engineering requirements (HOWs)

– Express engineering requirements in quantifiable terms

– Show direction for improvement using maximum , minimum , and nominal


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Simplified HoQ procedure‡ (cont.)

5. Determine the relationship between engineering parameters to the customer needs

– If there are no strong engineering parameters for a given customer need, there is a problem!


Indicator Meaning Strength

Strong relationship 9

Some relationship 3

Small relationship 1

Blank No relationship 0

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HoQ procedure‡ (cont.)

6. Correlate engineering relationships to determine interrelationships of design requirements

– Complete the “roof” of HoQ

7. Calculate the technical importance values and normalise.


Indicator Meaning

Strong positive relationship

Some positive relationship

Some negative relationship

# Strong negative relationship

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Spitfire example

Lab Session 3QFD Matrix

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Background

• Continue working on the car jack project.

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Objectives

1. Identify key design parameters (engineering parameters with units).

2. Map customer requirements to design parameters.

3. Find the relative importance of design parameters.

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Procedure

• Start with the ranked list of customer requirements and the relative importance factors that you generated in tutorial 1.

• Identify key design variables. All of the design variables need to be measurable and should be expressed in terms of a specific engineering unit such as viscosity, mass, force etc.

• Enter the customer requirements and design parameters into a spreadsheet matrix.

• Identify and quantify whether there is a relationship between each of the requirement/design parameter pairs.

– Use 0.9 for “strong”, 0.3 for “medium” and 0.1 for “weak” relationships.

Measure of design parameters

• Using this matrix of mappings generate a normalised set of weightings for the set of design parameters.

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Norm

aliz

ed Im

port

ance

of C

usto

mer

Requirem

ents

Desig

n V

aria

ble

#1

Desig

n V

aria

ble

#2

Desig

n V

aria

ble

#3

Mapped I

mport

ance o

f D

esig

n V

aria

ble

#1

Mapped I

mport

ance o

f D

esig

n V

aria

ble

#2

Mapped I

mport

ance o

f D

esig

n V

aria

ble

#3

Customer Requirement #1 26.67% 0.1 0.3 0.027 0.080 0.000



Customer Requirement #4 13.33% 0.3 0.040 0.000 0.000


Absolute Importance 0.207 0.340 0.040

Normalized Importance 35.2% 58.0% 6.8%

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Sanity checks

• Within the mapping matrix are there any empty rows?

– What might this suggest?

• Are they any empty columns?

– What might this suggest?

• Rank the design parameters by weighting and try and rationalise this.

– Are these priorities sensible?

– Do they accord with common sense and judgement?

– You cannot “cheat” by directly altering these but you can review the matrix entries.

Lecture 3 - Design Matrices

Documents

dr yoji akao

simplified

engineering

thin film

relative importance

large parts

flexible membranes

customer requirements