The increasing complexity of engineering systems has sparked increasing interest in multidisciplinary optimization (MDO). This paper presents a survey of recent publications in the field of aerospace where interest in MDO has been particularly intense. The two main challenges of MDO are computational expense and organizational complexity. Accordingly the survey is focused on various ways different researchers use to deal with these challenges. The survey is organized by a breakdown of MDO into its conceptual components. Accordingly, the survey includes sections on Mathematical Modeling, Design- oriented Analysis, Approximation Concepts, Optimization Procedures, System Sensitivity, and Human Interface. With the authors'' main expertise being in the structures area, the bulk of the references focus on the interaction of the structures discipline with other disciplines. In particular, two sections at the end focus on two such interactions that have recently been pursued with a particular vigor: Simultaneous Optimization of Structures and Aerodynamics, and Simultaneous Optimization of Structures Combined With Active Control.

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Multidisciplinary Aerospace Design Optimization: Survey of Recent Developments

The increasing complexity of engineering systems has sparked increasing interest in multidisciplinary optimization (MDO). This paper presents a survey of recent publications in the field of aerospace where interest in MDO has been particularly intense. The two main challenges of MDO are computational expense and organizational complexity. Accordingly the survey is focussed on various ways different researchers use to deal with these challenges. The survey is organized by a breakdown of MDO into its conceptual components. Accordingly, the survey includes sections on Mathematical Modeling, Design-oriented Analysis, Approximation Concepts, Optimization Procedures, System Sensitivity, and Human Interface. With the authors' main expertise being in the structures area, the bulk of the references focus on the interaction of the structures discipline with other disciplines. In particular, two sections at the end focus on two such interactions that have recently been pursued with a particular vigor: Simultaneous Optimization of Structures and Aerodynamics, and Simultaneous Optimization of Structures Combined With Active Control.

/pdf/multidisciplinary-aerospace-design-optimization-survey-of-ghzjxaiur6.pdf

Multidisciplinary aerospace design optimization: Survey of recent developments

Aeroelastic tailoring technology is reviewed with reference to the historical background, the underlying theory, current trends, and specific applications. The specific application discussed include the Transonic Aircraft Technology program, an Advanced Design Composite Aircraft, the Wing/Inlet Advanced Development program, and the forward-swept wing. Finally, the future of aeroelastic tailoring and the development of an aeroelastic tailoring analysis and design tool under the Automated Strength-Aeroelastic Design program are examined.

Aeroelastic tailoring - Theory, practice, and promise

Aeroelastic instabilities are among the factors that may constrain the flight envelope of aircraft and, thus, must be considered during design. As future aircraft designs reduce weight and raise performance levels using directional material, thus leading to an increasingly flexible aircraft, there is a need for reliable analysis that models all of the important characteristics of the fluid-structure interaction problem. Such a model would be used in preliminary design and control synthesis. A theoretical basis has been established for a consistent analysis that takes into account 1) material anisotropy, 2) geometrical nonlinearities of the structure, 3) unsteady flow behavior, and 4) dynamic stall for the complete aircraft. Such a formulation for aeroelastic analysis of a complete aircraft in subsonic flow is described. Linear results are presented and validated for the Goland wing (Goland, M., The Flutter of a Uniform Cantilever Wing, Journal of Applied Mechanics, Vol. 12, No. 4, 1945, pp. A197-A208). Further results have been obtained that highlight the effects of structural and aerodynamic nonlinearities on the trim solution, flutter speed, and amplitude of limit-cycle oscillations. These results give insight into various nonlinear aeroelastic phenomena of interest: 1) the effect of steady-state lift and accompanying deformation on the speed at which instabilities occur, 2) the effect on nonlinearities in limiting the amplitude of oscillations once an instability is encountered, and 3) the destabilizing effects of nonlinearities for finite disturbances at stable conditions.

Nonlinear Aeroelastic Analysis of Complete Aircraft in Subsonic Flow

Fixed membrane wings for micro air vehicles: Experimental characterization, numerical modeling, and tailoring

The principle of aeroelastic tailoring with advanced composite materials to increase the divergence speed of a forward swept wing has been demonstrated through low-speed wind tunnel tests The approach was to perform a low-cost, fairly simple wind tunnel test on a variable sweep cantilever wing model Available analytical methods were shown to accurately predict the divergence speed of both aluminum and composite plate structures in the subsonic speed range Methods were evaluated for predicting the onset of divergence using subcritical windtunnel data Results of the analyses and tests are presented in this report

Wind Tunnel Demonstration of Aeroelastic Tailoring Applied to Forward Swept Wings

Aeroelastic tailoring provides a measure of control over the interaction of aerodynamic loading and structural response during the design of composite lifting surfaces. A recent investigation involving the design, fabrication, and test of an aeroelastically tailored fighter wing was conducted to provide data for validating the design methodology. Three sets of composite wings with different design objectives were tested in addition to a set of rigid steel wings. The static aeroelastic tests featured the measurement of model forces, pressure distributions, and deflected shapes in the transonic regime. Test results are compared with analytical predictions and show significant aeroelastic benefits.

Design, analyses, and model tests of an aeroelastically tailored lifting surface

: The principle of aeroelastic tailoring with advanced composite materials to increase the divergence speed of a forward swept wing has been demonstrated through low speed wind tunnel tests. The approach was to perform a low cost, fairly simple wind tunnel test on a variable sweep cantilever wing model. Available analytical methods were used and were shown to accurately predict the divergence speed of both aluminum and composite plate structures in the subsonic speed range. Methods were evaluated for predicting the onset of divergence using subcritical wind tunnel data. Results of the analyses and tests are presented.

Michael H. Shirk

Papers

Aeroelastic tailoring - Theory, practice, and promise

Wind Tunnel Demonstration of Aeroelastic Tailoring Applied to Forward Swept Wings

Design, analyses, and model tests of an aeroelastically tailored lifting surface

Aeroelastic tailoring - Theory, practice, and promise

A Demonstration of the Principle of Aeroelastic Tailoring Applied to Forward Swept Wings