Development of an Aeroelastic Stability Module for Wing Planform Optimization

Abstract

This paper presents an aeroelastic stability module suitable for aircraft conceptual design applications, in which structural variables and wing planform parameters are both part of the design space. Aeroelastic stability analysis is rarely included in the conceptual design phase and often by means of analytical or statistical based methods. Here, physics-based numerical disciplinary analyses are employed for the computation of the aeroelastic stability constraint: a beam-based structural \acrlong{fem} and a 3D potential aerodynamic \acrlong{bem} are employed for structural modal analysis and unsteady aerodynamic analysis, respectively. Flutter speed and continuous flutter constraint definitions are both implemented and compared; advantages and drawbacks of the two approaches are discussed from a theoretical and practical perspective. The model is completely differentiated including the derivatives of the structural modal shapes, which cannot be neglected for wing planform design variables. The differentiation procedure is verified by comparison with equivalent finite difference results and an extensive sensitivity studies for a simple cantilevered wing model shows the suitability of the developed module for aircraft design applications.