lecture 3 - design matrices
TRANSCRIPT
SESG-2005
Engineering Design and Structural Analysis Methods
James Scanlan, Mohamed Torbati, and Hakki Eres18 February 2010
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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
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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
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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.
‡Product Design, Kevin Otto and Kristin Wood, 2001.
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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)
‡Product Design, Kevin Otto and Kristin Wood, 2001.
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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
‡Product Design, Kevin Otto and Kristin Wood, 2001.
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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.)
‡Product Design, Kevin Otto and Kristin Wood, 2001.
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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
‡Product Design, Kevin Otto and Kristin Wood, 2001.
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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!
‡Product Design, Kevin Otto and Kristin Wood, 2001.
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.
‡Product Design, Kevin Otto and Kristin Wood, 2001.
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 #2 13.33% 0.9 0.1 0.120 0.000 0.013
Customer Requirement #3 26.67% 0.3 0.1 0.000 0.080 0.027
Customer Requirement #4 13.33% 0.3 0.040 0.000 0.000
Customer Requirement #5 20.00% 0.1 0.9 0.020 0.180 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.