Axiomatic Design Flashcards
What is axiomatic design?
- 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
descriptive method?
describing how things are done in practice
- guidlines
- not so precise of how and when?
prescriptive method?
Exactly what should to and how to do it
what is design?
An interaction process where we are going between WHAT (functional requirements) we and to a achieve and HOW (design p?) we will achieve this
Axiomatic hierarchic FR-DP decomposition?
mapping between functional domain to the physical domain
what is functional interference?
When two functions realized by the solution is coupled or functionally dependent
what is good characteristics?
Axiom 1.
The independence axiom:
- maintain independence between functional requirements and solutions
Axiom 2.
The information axiom:
—> simplicity
—> minimize the information content
definition of an axiom?
Principals always true and impossible to falsify
physical integration?
Might be good but not always
- To inegrate to uncoupled functional requirement is good according to
what is design parameters?
- 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
map between functional domain and physical domain?
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
Most important:
- FRs and DPs shall be functionally independent
2. Minimize the number of FRs and DPs
Functional coupling analysis?
Linear systems?
If DPs influences all FRs
—> axiom 1 is not fulfilled
—> completely coupled design
—> functional interferences
Uncoupled design?
diagonal symmetric a matrix —> each DP influences only its own FR —> axiom 1 is fulfilled
Semi-coupled design?
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
design synthesis and analysis?
- 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? —> ?
More FR:s than DPs?
Theorem 2
- The design solution is coupled
- All FRs can not be fulfilled
Theorem 2?
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
More DPs than FRs?
- Uncoupled solution but DP3 has no function or influence at all —> unnecessary
- redundant design
- coupled design
Theorem 3?
If the number of DPs bigger than FRs the design solution is coupled orreduntant
Theorem 4?
The ideal design solution the
- FR=DP
Theorem 5?
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
What does Axiomatic design synthesis strive for?
Uncoupled or semi-coupled design solutions
- diagonal or triangular matrices
Axiomatic design analysis and evaluation?
- set up the design equation and determine design matrix
- Analyze the design matrices and their couplings
- Change solutions and remove seven couplings
- determine coupling degree
- Compare different solutions design matrices