Bioinspired lightweight structural design of distributed propulsion wing inspired by the toco toucan beak architecture

The distributed propulsion wing (DPW), which deeply integrates distributed ducted propulsion with the wing surface, represents an advanced configuration of distributed electric propulsion aircraft. This configuration imposes urgent demands on structural lightweighting and high-performance design. However, the embedded ducts introduce quasi-periodic porous characteristics into the structural design domain, limiting the layout space for conventional spars and resulting in a high weight proportion of ducted propulsion components. Moreover, the structural design of the DPW must pay additional attention to special issues such as local duct deformation and its effect on tip clearance. Although a shell structure can conform to complex curved surfaces, it suffers from significant stability problems. Consequently, neither approach can simultaneously achieve lightweighting and high load-bearing efficiency.To address these challenges, inspired by the lightweight and high-performance architecture of the toco toucan beak, this study proposes a bioinspired lightweight structural design method tailored for the DPW. First, the architectural features of the toucan beak are deconstructed to extract the bioinspired design objectives. Second, a spatial bioinspired lattice generation method is established based on 3D Voronoi tessellation and Catmull-Clark subdivision surfaces, together with a performance-oriented multi-level tuning strategy. Then, static tests on a representative specimen are conducted using a universal testing machine and non-contact image-based measurement techniques; the overall and local responses are obtained and compared with finite element simulations, validating the feasibility of the design method and the accuracy of the numerical model. Finally, the method is applied to a DPW segment, and its structural performance is compared with that of a conventional pure shell structure under equal-mass conditions.The results show that, compared with the equal-mass conventional pure shell structure, the bioinspired structure achieves a 44.8% reduction in maximum displacement, a 21.3% reduction in the stress level coefficient, and an 81.0% increase in the first-order buckling load, demonstrating higher global stiffness, more favorable stress distribution, superior buckling resistance, and improved local stiffness of the duct, thereby effectively addressing the global-local stiffness coordination requirements. This study not only provides a feasible solution and a design/analysis tool for lightweight structural design of the DPW, but also offers a transferable methodology—including the bioinspired structure generation method and tuning strategy—for applying bioinspired structures to other objects.