Axiomatic Design

Question 1

What is axiomatic design?

Answer 1

• A design theory based in basic principles related to product properties and characteristics
• Evaluation od decision consequences must be based on basic axioms
  —>product focus
  —> prescriptive

Hierarchic functional and physical top down composition supporting synthesis

Functional coupling

Question 2

descriptive method?

Answer 2

describing how things are done in practice

• guidlines
• not so precise of how and when?

Question 3

prescriptive method?

Answer 3

Exactly what should to and how to do it

Question 4

what is design?

Answer 4

An interaction process where we are going between WHAT (functional requirements) we and to a achieve and HOW (design p?) we will achieve this

Question 5

Axiomatic hierarchic FR-DP decomposition?

Answer 5

mapping between functional domain to the physical domain

Question 6

what is functional interference?

Answer 6

When two functions realized by the solution is coupled or functionally dependent

Question 7

what is good characteristics?

Answer 7

Axiom 1.
The independence axiom:
- maintain independence between functional requirements and solutions

Axiom 2.
The information axiom:
—> simplicity
—> minimize the information content

Question 8

definition of an axiom?

Answer 8

Principals always true and impossible to falsify

Question 9

physical integration?

Answer 9

Might be good but not always

- To inegrate to uncoupled functional requirement is good according to

Question 10

what is design parameters?

Answer 10

• Functional carrier
• Organ
  —>
• Means
• Design solution
• Functional feature
• Product/Systems
• sub-systems
• Component
• Design features

NOT the same thing as a component structure,
might be e.g.a hole

Question 11

map between functional domain and physical domain?

Answer 11

E.G.
FRs:
-Toast bread
—> heat bread
—> handle bread
—> carry parts

DPs:
- Toaster
—> heating systems
—> Load/eject system
—> Chassis

Each FRs can map to one DPs

Question 12

Most important:

Answer 12

1. FRs and DPs shall be functionally independent

2. Minimize the number of FRs and DPs

Question 13

Functional coupling analysis?

Answer 13

Linear systems?

If DPs influences all FRs
—> axiom 1 is not fulfilled
—> completely coupled design
—> functional interferences

Question 14

Uncoupled design?

Answer 14

diagonal symmetric a matrix —> each DP influences only its own FR —> axiom 1 is fulfilled

Question 15

Semi-coupled design?

Answer 15

lower symmetric matrix(?)

Each FR can be fulfilled “independently” of each other if it is for in correct order”

• use boundary conditions e.g.
• axiom 1 is fulfilled
• rather robust

Question 16

design synthesis and analysis?

Answer 16

• non-zero coefficient if the DP effect the FR
• zero coefficient if DP do NOT affect FR
• make lower triangular—> the most zeros in row 1
• if not lower triangular is possible? —> ?

Question 17

More FR:s than DPs?

Answer 17

Theorem 2

• The design solution is coupled
• All FRs can not be fulfilled

Question 18

Theorem 2?

Answer 18

More FRs than DPs but triangular sub-matrix

—> solution can be decoupled by adding DPs so that the number of FRs= the number of DPs

Question 19

More DPs than FRs?

Answer 19

1. Uncoupled solution but DP3 has no function or influence at all —> unnecessary
2. redundant design
3. coupled design

Question 20

Theorem 3?

Answer 20

If the number of DPs bigger than FRs the design solution is coupled orreduntant

Question 21

Theorem 4?

Answer 21

The ideal design solution the

- FR=DP

Question 22

Theorem 5?

Answer 22

If FRs for an existing design solution are changed or added, the existing solution can not fulfill the new FRs
A new/ modified solution must be developed

Question 23

What does Axiomatic design synthesis strive for?

Answer 23

Uncoupled or semi-coupled design solutions

- diagonal or triangular matrices

Question 24

Axiomatic design analysis and evaluation?

Answer 24

1. set up the design equation and determine design matrix
2. Analyze the design matrices and their couplings
3. Change solutions and remove seven couplings
4. determine coupling degree
5. Compare different solutions design matrices

Question 25

Name 4 points of departure for the scientific base!

Answer 25

1. A design decision influences all product life cycle phases and particularly the downstream steps in the product development process 2. A base for design science must contain principles and methods supporting decision making 3. Evaluation of decision consequences must be based on axioms 4. Products and processes are hierarchic and can be decomposed in Hierarchic structures

Question 26

What is functional requirements? (FRs)

Answer 26

The goal (WHAT) is specified in the functional domain

Question 27

what is design parameters? (Dp?

Answer 27

Solutions (HOW) fulfilling the goal are generated and defined in the physical domain

Question 28

Axiom 1? (the independence axiom?

Answer 28

Maintain the independence of functional requirements and solutiona

Question 29

Axiom 2 (the information axiom)

Answer 29

Minimize the information content

Question 30

When can it be GOOD to integrate two uncouple design solutions?

Answer 30

To integrate two uncoupled design solutions which fulfill their own FRs without influencing the fulfillment of each others FRs negatively IS GOOD according to axiom 2 (simplify)

Question 31

When can it be NEGATIVE to integrate two uncouple design solutions?

Answer 31

To integrate and thereby functionally couple two design solutions, so they will influence the fulfillment of each others FRs negatively is BAD according to axiom 1 (independence of requirements and solutions)

Question 32

Give an example with the hammer head!

Answer 32

FR1=Hit nails FR2= remove nails hammer with integrated nail remover and hitting surface Good according to axiom 2 —> less complexity "Bad" according to axiom —> dependent solutions

Question 33

when you have more design parameters than components?

Answer 33

Integration of function carriers (organs) /design parameters

Question 34

when you have more components than design parameters?

Answer 34

A function is realized by interacting components

Question 35

Is a DP structure the same thing as a component?

Answer 35

NO | - for example a clearance seal empty space) might be a design parameter but is NOT a component

Question 36

Describe the functional structure of a toaster!

Answer 36

``` Toast bread - Heat bread —> generate heat —> connect electricity —> control heat - Handle bread —> eject bread —> hold bread - Carry parts —> hold parts —> Cover parts ```

Question 37

Discrive physical structure of a toaster!

Answer 37

``` Toaster - Heating system —> hot wire —> connecting system —> timer - Load/Ejectc —> spring ejector —> wier box - Chassis —> frame —> cover ```

Question 38

Concept generation strategy? with FR & DP

Answer 38

1. Derive as many sub-solution alternatives as possible to each sub-function on current hierarchical level 2. Combine sub-solution alternatives to total solution alternatives on current hierarchical level 3. Choose the best total solution alternative on current hierarchical level 4. Go to next lower hierarchical level and turn to 1

Question 39

Name 3 important conclusions of axiomatic design!

Answer 39

1. FR and Dp stal be functionally independent 2. Minimize the number of FRs as each FR requires a solutions that adds to the complexity - (combine FR) - (remove redundant (FR) 3. FR shall not be decomposed into the next hierarchical level before a solution (DP) exists

Question 40

Synthesis and analysis within Axiomatic design?

Answer 40

SYNTHESIS Hierarchic functional and physical top-down decomposition supporting synthesis ANALYSIS Functional coupling analysis (complexity/information analysis)

Question 41

what is a theorem?

Answer 41

a non-evident proposition that can be deduced from one or many axioms

Question 42

what is corollary?

Answer 42

A non-evident proposition that can be deduced from one or many axioms or down accepted basic knowledge

Question 43

How is functional coupling analysis performed?

Answer 43

The design equation: | FR=A*DP