Systems Design - New Paradigm

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Systems Design - New Paradigm

• K Sudhakar
• Centre for Aerospace Systems Design Engineering
• http//www.casde.iitb.ac.in/
• January 28, 2004

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Systems Design
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Systems Engineering
Systems Engineering? Need to view things from
one level higher than your work requires
Meta Design
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Meta-Design

• Increase breadth of knowledge used in decisions
• Increase depth of knowledge used in decisions
• Shorten design cycle time
• Ability to systematically explore design space
• - -

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Meta Design ? MDO
MDO Elements
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• Researchers Perception
• Multi-disciplinary Increased breadth
• Design process of translating requirements into
  product specifications.
• Optimization Formal method of locating the
  best under constraints
• Implies use of high fidelity tools. Increase
  depth.

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• Industry Perception
• Not a turnkey solution to design!
• Only a tool in the hands of designer to
• State design problems formally
• Integrate appropriate fidelity analysis
• Explore design space
• Improve design starting from a baseline

If we can find an optima we will be happy! If we
find global optima we will celebrate!
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Systems Design
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An Example HSCT (1991-99)!

• HSCT-2
• 5 design variables, 6 constraints
• WINGDES, ELAPS, Range equation, engine deck
• Time for one cycle 10 minutes
• HSCT-3
• 7 design variables, 6 constraints
• ISAAC, COMET, Range equation. Engine deck
• Time for one cycle 3 hours
• HSCT-4
• 271 design variables, 31,868 constraints
• CFL3D, USSAERO, GENESIS, FLOPS, ENG10
• Time for one cycle 3 days

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HSCT - 4

• Detailed problem definition took more than 1 year
  to extract from people
• Requirements document touched 100 pages merely to
  define analysis process, tools used and data flow
• 90 of work went into preparing analysis codes
  for MDA and integrating them in a proper sequence

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Where are we?

• Strengths exist in disciplinary analysis
• No focus on Analysis for Design
• No focus on verification / validation to
  characterize uncertainties
• No attempt to capture knowledge with traceability

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• CASDE _at_ Workshop on Framework for System
  Analysis, ISSA, New Delhi, October 13, 2003
• Need for groups to
• Define design problem
• Define needs for Analysis for Design
• Extract / Establish traceability
• Perform Verification / Validation to characterize
  uncertainty
• Explore design methodologies

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• New Paradigms
• MDO the process
• Frame Works to deploy the process
• Multi-criteria decision making
• Design under uncertainty
• Components
• Surrogate Modeling (DOE, RSM, DACE)
• Sensitivity Analysis

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Design Under Uncertainty

• How to assemble System Analysis
• How to state design problem?

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Frame Work

• Essential infrastructure
• Disciplinary autonomy, but system level
  integration. (Distributed, heterogeneous
  environment)
• Tools availability
• Requirement Capture for Frame Work?
• Commercial Frame Works iSIGHT, Phoenix
  Integration, . . .
• CASDE MDO FrameWork Version-II (March 2004)

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MDO Framework

• Architectural design - Intuitive GUI, OO
  principles, standards based
• Problem formulation - Iterative branching
  formulations, legacy codes, multiple optimizers
• Problem execution - Automatic execution,
  parallel distributed
• Information access DB management
  visualization, monitoring

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3D-Duct An Example

• Duct design in the past?
• Is improvements in breadth, depth possible?
• Statement of design problem?
• Analysis Tools - Identification, VV and
  Integration
• Focus on shrinking design cycle time
• Design process?

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3D-Duct Problem Formulation
Entry Exit
Location and shape (Given)

• Objective/Constraints
• Pressure Recovery
• Distortion
• Swirl

Optimum geometry of duct from Entry to Exit ?
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3D-Duct Automation for CFD
Duct Parameters (ß1, ß2, ay, az)
Clustering Parameters
Generation of structured volume grid using
parametrization
Generation of entry and exit sections using
GAMBIT
Entry Exit sections
Mesh file
Conversion of structured grid to unstructured
format
Conversion of file format to CGNS using FLUENT
Unstructured CGNS file
Continuation Solution
CFD Solution using FLUENT
End-to-end (Parameters to DC60) automated CFD
Cycle.
CFD Solution
DC60
Objective/Constraints evaluation Using UDFs
(FLUENT)
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3D-Duct Automation for Design
Duct Parameters (ß1, ß2, ay, az)
Generation of structured volume grid using
parametrization
Entry Exit sections
Conversion of structured grid to unstructured
format
Optimization
Unstructured CGNS file
Continuation Solution
CFD Solution using FLUENT
CFD Solution
DC60
Objective/Constraints evaluation Using UDFs
(FLUENT)
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3D-Duct Design Space Reduction
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3D-Duct Simulation Time

• Strategies
• Continuation Method
• Parallel execution of FLUENT on a 4-noded Linux
  cluster

Time for simulation has been reduced to around
20.
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3D-Duct Design Process
LFA Optima
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CONCURRENT ENGINEERING Vs MDO
Source AIAA MDO White Paper, 1991
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• Visithttp//www.casde.iitb.ac.in/MDO/
• Thank You