A CAD-Free Approach to High-Fidelity Aerostructural Optimization

Abstract

Geometry parametrization for high-fidelity multidisciplinary optimization is an important and complex problem. We present a CAD-free geometry parametrization method using a free-from deformation volume approach. This approach yields several important advantages over other parametrization techniques, the most of important of which is the efficient computation of analytic derivatives for gradient-based optimization. A parallel, hybrid, algebraic-linear-elasticity mesh perturbation scheme which produces high quality perturbed meshes with low computational effort is also presented. We couple an Euler CFD solver with a finite-element model that uses fourth-order degenerate shell elements. As a demonstration problem, we perform the aerostructural redesign of a subsonic wing for transonic flight conditions. We show that this optimization problem captures some of the complex multidisciplinary trade-offs inherent in wing design.

Multipoint High-Fidelity Aerostructural Optimization of a Transport Aircraft Configuration

“…We use a free form deformation (FFD) volume approach to make geometric perturbations to the geometry. Further information on our approach can be found in Kenway et al [54]. The main wing planform variables, span, sweep, chord, and twist, are all global variables, since they directly affect the geometry of both the aerodynamics and the structures.…”

Aerostructural optimization of the Common Research Model configuration

“…MACH uses the hybrid algebraic-linear elastic approach described in Kenway et al [20]. However, the relatively simple mesh topology of the DPW5 meshes allows us to use the algebraic scheme alone, which is a delta-based transfinite interpolation method [21].…”

Aerodynamic Design Optimization Studies of a Blended-Wing-Body Aircraft

“…The mesh perturbation scheme used in this work is a hybridization of algebraic and linear elasticity methods [21]. The idea behind the hybrid warping scheme is to apply a linear-elasticity-based warping scheme to a coarse approximation of the mesh to account for large, low-frequency perturbations, and to use the algebraic warping approach to attenuate small, high-frequency perturbations.…”

“…We use a free form deformation (FFD) approach to parametrize the geometry [21]. The FFD volume parametrizes the geometry changes rather than the geometry itself, resulting in a more efficient and compact set of geometry design variables, and thus making it easier to handle complex geometric manipulations.…”