Design Modelling

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Design Modelling

• TMR4115
• Friday, August 22 2003
• Prof. Stein Ove Erikstad

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Agenda

• Recapturing last week
• characteristics marine systems design
• Basic reasoning steps in design
• how can we model the design models?
• Modelling in design
• basic model elements
• modelling examples

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Recapturing last week

• The contents of the preliminary ship design

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Models and Methods in Design
Reality
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The Design Paradox
Postpone decisions
Increase knowledge
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Activities and Events
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Syntax vs Semantics
(hull form propeller) ? (required SHP) (hull
form) ? (seakeeping behaviour) (hull form,
propeller, machinery) ? (ship speed) (all ship
systems) ? (total cost)
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Design vocabularyV
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Design descriptionsD

• Contract specification
• CAD model
• Equipment data sheets
• P/ID diagrams

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Design interpretationsI

• Intended interpreations
• goals, objectives, constraints
• Inferred interpretations
• actual performance based on analysis

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Design Knowledge

• Syntactic knowledge, Ks
• knowledge about how to form meaningful design
  description
• Semantic knowledge, KI
• knowledge about how to derive the meaning, i.e.
  interpret, the design
• Parallel to languages

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Inference processes in design Deduction
Ki ?x DW(x) ? V(x) ? Resistance(x) f(DW(x),
V(x)) D DW(ShipA) 200.000 ? V(ShipA)
15 I Resistance(ShipA) 1200

• E.g. design analysis

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Inference processes in design Deriving design
descriptions
Ki ?x DW(x) ? V(x) ? Resistance(x) f(DW(x),
V(x)) I Resistance(ShipA) 1200 D DW(ShipA)
200.000 ? V(ShipA) 15

• E.g. linear optimisation, simplex

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Inference processes in design Generating designs

• E.g. systematic parameter variation

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Inference processes in designAcquiring design
knowledge

• E.g. towing tank

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Design modellingOptimization