COMPLETE CONFIGURATION AERO-STRUCTURAL OPTIMIZATION USING A COUPLED SENSITIVITY ANALYSIS METHOD Joaquim R. R. A. Martins Juan J. Alonso James J. Reuther Department of Aeronautics and Astronautics Stanford University 9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Atlanta, GA, September 2002 1
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COMPLETE CONFIGURATION AERO-STRUCTURALOPTIMIZATION USING A COUPLED SENSITIVITY
ANALYSIS METHOD
Joaquim R. R. A. MartinsJuan J. Alonso
James J. Reuther
Department of Aeronautics and AstronauticsStanford University
9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Atlanta, GA, September 2002 1
Outline
• Introduction
– High-fidelity aircraft design optimization– The need for aero-structural sensitivities– Sensitivity analysis methods
– Optimization problem statement– Aero-structural sensitivity validation– Optimization results
• Conclusions
9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Atlanta, GA, September 2002 2
High-Fidelity Aircraft Design Optimization
• Start from a baseline geometry providedby a conceptual design tool.
• Required for transonic configurationswhere shocks are present.
• Necessary for supersonic, complexgeometry design.
• High-fidelity analysis needs high-fidelityparameterization, e.g. to smooth shocks,favorable interference.
• Large number of design variables andcomplex models inccur a large cost.
9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Atlanta, GA, September 2002 3
Aero-Structural Aircraft Design Optimization
• Aerodynamics and structures are coredisciplines in aircraft design and are verytightly coupled.
• For traditional designs, aerodynamicistsknow the spanload distributions that leadto the true optimum from experience andaccumulated data. What about unusualdesigns?
• Want to simultaneously optimize theaerodynamic shape and structure, sincethere is a trade-off between aerodynamicperformance and structural weight, e.g.,
Range ∝ L
Dln
(Wi
Wf
)
9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Atlanta, GA, September 2002 4
The Need for Aero-Structural Sensitivities
OptimizationStructural
OptimizationAerodynamic
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 10
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Spanwise coordinate, y/b
Lift
Aerodynamic optimum (elliptical distribution)
Aero−structural optimum (maximum range)
Student Version of MATLAB
Aerodynamic Analysis
Optimizer
Structural Analysis
• Sequential optimization does not lead tothe true optimum.
9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Atlanta, GA, September 2002 26
Conclusions
• Presented a framework for high-fidelity aero-structural design.
• The computation of sensitivities using the aero-structural adjoint isextremely accurate and efficient.
• Demonstrated the usefulness of the coupled adjoint by optimizing asupersonic business jet configuration with external shape and internalstructural variables.
9th AIAA/ISSMO Symposium on Multidisciplinary Analysis and Optimization Atlanta, GA, September 2002 27