3D Topology Optimization of Aircraft Wings with Conventional and Non-conventional Layouts: A Comparative Study

Adoption of topology optimization in aircraft structural design can allow designers to explore non-intuitive design configurations without making assumptions about the arrangement of the structural components. In this work, we compare wing structural design optimization approaches to reduce the structural weight of the NASA Common Research Model wing for next-generation long-range transonic aircraft design. In the first approach, the outer mold line of the wing is populated with a traditional skin, rib, and spar layout using a finite element discretization containing shell elements. In the second design approach, the entire solid domain enclosed by the wing outer mold line is considered as a design space to allow for non-intuitive material distribution. We use a large-scale three-dimensional aero-elastic topology optimization framework to minimize the compliance of the wing structure under coupled aeroelastic and gravity loads for a prescribed final wing mass in both cases. For a fixed structural weight, we explore the similarities and differences between the two design approaches. We demonstrate that in certain cases, the reduced design space of the wing box layout can be used to obtain similar features and performance as that of an exhaustive full design space search at a fraction of the computational time (60%-80%). The resulting geometry of the shell-based topology optimization is easier to manufacture at large scale as thin plates. However, the non-conventional wing layout can exploit the full design space more efficiently to account for any local effects of the material distribution.