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Multidisciplinary Optimization of an Aircraft Wing/Tip Store in the Transonic Regime

Authors: Srinivasan Janardhan; Ramana V. Grandhi; WRIGHT STATE UNIV DAYTON OH DEPT OF MECHANICAL AND MATERIALS ENGINEERING
Abstract:
In this research, a multidisciplinary optimization procedure is described to delay the occurrence of store-induced flutter of an aircraft wing/ tip store configuration. A preliminary design procedure was developed to enhance the performance characteristics of an aircraft wing model in the transonic Mach number regime. A wing/tip store configuration with the store center of gravity (c.g.) located at the 50% aerodynamic tip chord was chosen for structural optimization. The aircraft wing structural weight was chosen as the objective function with constraints on natural frequency, stress and flutter. Automated Structural Optimization System (ASTROS) and Computational Aeroelasticity Program-Transonic Small- Disturbance (CAP-TSD) were the computational tools employed to perform the structural optimization and subsequent aeroelastic (mutual interaction between the aerodynamics and structural deformation) analysis in the transonic regime. This work showed that an improved store- induced flutter speed was obtained by increasing the separation between the first two natural frequencies of the wing structure. These results were compared with the results of those cases in which the flutter constraints were incorporated, along with the stress and frequency constraints, in the optimization problem. The addition of the flutter constraint resulted in a negligible increase in flutter speed when compared with the flutter speed obtained from optimization with only frequency and stress constraints.

Limitations: APPROVED FOR PUBLIC RELEASE
Pages: 38
Report Date: JUL 2003
Contract Number: F49620-01-1-0179
Report Number: A601714
Keywords relating to this report:
*AIRCRAFT DESIGN
*TRANSONIC AIRCRAFT
AERODYNAMICS
AIRCRAFT MODELS
AUTOMATION
CENTER OF GRAVITY
EXTERNAL STORES
FLUTTER
MACH NUMBER
OPTIMIZATION
RESONANT FREQUENCY
STRUCTURAL PROPERTIES
WING TIPS
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