Transcript Slide 1

Aircraft Conceptual
Design Optimization
Kristian Amadori, Dr. Christopher Jouannet
Outline
 Introduction
 Design Framework
 Test Case 1
 Conclusions
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Introduction
 System design is today characterized by:
 Distribution
 Collaboration
 Competition
Subsystem/
design team
Subsystem/
design team
Subsystem
interface
System / system
integration group
Subsystem/
design team
Subsystem/
design team
Subsystem/
design team
 We need tools for distributed system design that
handles these characteristics in early design stages
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Why?
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Introduction
Disciplinens
Table from: Nickol, C., “Conceptual Design Shop”, Presentation to Conceptual Aircraft Design Working Group
(CADWG21), Sept. 2004
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Design Framework
 Based on Web Service Technology
 Implements so-called Service Oriented Architecture (SOA)
Computational
Computational
model
model
User Client
Integration Service
and Data Repository
Network (SOAP messages)
Computational
Computational
model
model
User Client
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Computational
Computational
method
method
Design Framework
 Connect together tools from different disciplines
 Maintain system perspective
Spread sheet with
design analysis and
optimization tools
 Allow for distribution
 Design optimization
System Model
Wing
Wing
Fuselag
Fuselage
e
Perform
ance
Performance
Aircraft Sizing Model
Electric
Electric
Power
System
Power
Propulsi
Structure
on
Fuel
System
Fuel System
Sstem
Stability &
Stability
Control
&
Control
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Propulsi
Propulsion
on
Actuation
Actuatio
System
n
System
Aerodyn
amics
Aerodynamic
Optimization
Parametric CAD Modeling
 Flexible geometries
 Robustness
 Hierarchical
 Associative
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Parametrization
Various stages of Morphological instantiation
b
Script
Based
Relation
if shape = ”sq”
h { h = 10, b = h }
else { h = 10,
b = 2*h }
b
Mathematic Based
Relation
h
h = 10
b = 2*h
b
Parameterization
Fixed Object
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h = 10
h b = 20
Parametrization
Various stages of Topological instantiation
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Parametric CAD Modeling
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Parametric CAD Modeling
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Parametric CAD Modeling
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Parametric CAD Modeling
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Parametric CAD Modeling
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Aerodynamics
 PANAIR
 3D
 Capable of analyzing any geometry
 Fast
 (Relatively) accurate
 Tornado can be used (integrated to the framework)
 Other CFD tools can be used if jugsed necessary
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Test Case:
Wing-Box Design Optimization
 Wing-box structure optimization, given the air loads and a
predefined shape:
 Position, orientation and thickness of ribs
 Spars thickness
 Skin thickness
 Number of ribs
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Test Case:
The Optimization Problem
 Problem formulated as:
min WW 
s.t.  MAX   Allowed
 Soft contraint formulation:

  MAX 
P  K  

  Allowed 
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Test Case:
Results (a)
 Optimization stopped after 1000 trials with number of ribs are
fixed to 10 (left) or let vary between 5 to 15 (right)
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Test Case:
Results (b)
 Optimization stopped after 20000 trials with number of ribs are
fixed to 10 (left) or let vary between 5 to 15 (right)
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Test Case :
Results Summary
1
0,9
0,8
Weight
Max Stress
Obj. Funct.
0,7
0,6
0,5
Fixed Nr.
Var. Nr.
1000 Iterations
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Fixed Nr.
Var. Nr.
20000 Iterations
Conclusions
 Framework architecture that focuses on its flexibility of
application
 How to proficiently include high-end CAD system into initial
geometry generation
 Higher model flexibility increases chance to find better solution
 KBE-techniques
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