Against the wind: A load-bearing, yet durable, kite inspired by insect wings

Durability and load-bearing are difficult to be combined in engineering systems. Hence, in majority of man-made structures, the two characteristics are typically mutually exclusive. Nature, however, has provided us with design strategies, through which many biological systems have overcome this conflict. Insect wings represent a striking example of such a combination. A key to this lies in the presence of vein joints. Here we 3D printed bio-inspired joints, akin to those of insect wings and tested their mechanical performance under both static and cyclic loadings. We used the so-called ‘flexible joints’, which had a high durability, and engineered them to further enhance their load-bearing capacity. We then implemented them into the design of the first 3D printed bio-inspired kite. The manufactured kite showed a stable flight and withstood loads induced by strong wind gusts without failure. The concept developed here can be applied to other engineering designs that pursue a compromise between load-bearing and durability. At the end, we used our data to better understand the complexities of insect wings with respect to their local and global deformations and fracture resistance.