AIAA 2003–3429 High-Fidelity Aero-Structural Design Using a Parametric CAD-Based Model

This paper presents two major additions to our high-fidelity aero-structural design environment. Our framework uses high-fidelity descriptions for both the flow around the aircraft (Euler and Navier-Stokes) and for the structural displacements and stresses (a full finite-element model) and relies on a coupled-adjoint sensitivity analysis procedure to enable the simultaneous design of the shape of the aircraft and its underlying structure to satisfy the measure of performance of interest. The first of these additions is a direct interface to a parametric CAD model that we call AEROSURF and that is based on the CAPRI Application Programming Interface (API). This CAD interface is meant to facilitate designs involving complex geometries where multiple surface intersections change as the design proceeds and are complicated to compute. In addition, the surface geometry information provided by this CAD-based parametric solid model is used as the common geometry description from which both the aerodynamic model and the structural representation are derived. The second portion of this work involves the use of the Finite Element Analysis Program (FEAP) for the structural analyses and optimizations. FEAP is a full-purpose finite element solver for structural models which has been adapted to work within our aero-structural framework. In addition, it is meant to represent the state-of-the-art in finite element modeling and it is used in this work to provide realistic aero-structural optimization costs for structural models of sizes typical in aircraft design applications. The capabilities of these two major additions are presented and discussed. The parametric CAD-based geometry engine, AEROSURF, is used in aerodynamic shape optimization and its performance is compared with our standard, in-house, geometry model. The FEAP structural model is used in optimizations using our previous version of AEROSURF (developed in-house) and is shown to provide realistic results with detailed structural models.