A Fast MDO Tool for Aeroelastic Optimization in Aircraft Conceptual Design

Abstract

This paper presents a design tool based on computational methods for the aero-structural analysis and optimization of aircraft layouts at the conceptual design stage. The whole methodology is based upon the integration of geometry construction, aerodynamic and structural analysis codes that combine depictive, computational, analytical, and semiempirical methods, validated in an aircraft design environment. The two primary modules are presented: CADac (Computer Aided Design Aircraft) for parametric geometry handling and NeoCASS (Next generation Conceptual Aero-Structural Sizing Suite) for structural sizing and numerical aeroelastic analysis. The aero-structural numerical kernel enables the creation of efficient low-order, high fidelity models which makes particularly suitable to be succesfully used within an MDO framework to drive the optimization tool into the most appropriate direction. Indeed, solving adverse aeroelastic issues like divergence, control surfaces reversal, flutter, increased drag at cruise speed due to structural deformability may require considerable changes in the structural design, limitations in flight envelope or weight penalties. The late discovery of this type of issues may result in significant cost increases and, in some cases, it may even require to actually close the project. In order to overcome the insurgence of these issues, the influence of deformability on flight and handling performances, on structural weight and on design costs needs to be taken into account as early as possible in the design process.