Studies On The New-style Reticulately Stiffening Thin-wall Space Structures By Bionic Modeling Of Dragonfly Wings

Firstly, through analyzing the high-resolution dragonfly wing pictures from sample tests, the unique feature of the reticulate vein structure and the details of dragonfly wings were figured out, then several computational models based on a dragonfly fore-wing were established by using ANSYS, where pipe 20 and shell 43 elements were used in modeling of the veins and the membrane, respectively, taking the contribution of the geometrically non-linear effect into account, these models subject to different loading cases were analyzed respectively so as to explore the superiorities of the wing structure.Secondly, the special roles of the wing veins, membrane and naevus in the wing structure were studied. The wing veins were classified into three groups in accordance with their distribution and sizes. The effects of the vein sizes and material property on the performance of the wing structure were evaluated by defining different geometries and material parameters of them, it is shown that the size variation and distribution of the veins in different zones are quite reasonable. Then, the emphasis was concentrated on the stress stiffening effect of the membrane, and four simple models were established by borrowing the unique grid forms of dragonfly wings. It demonstrates that the effect plays an important role in ensuring the wing working efficiently, furthermore, the compatibility of the veins and membrane at a deformed state was also illuminated. In addition, the unique function of the wing naevus was also explored, and the effects of the naevus location and its density variation on the vibrating performance were checked so as to explore the mechanism of the naevus in eliminating or suppressing the wing quivering effect.Finally, three new-style reticulately stiffening thin-wall space structural models were proposed, where steel tubes and carbon fiber composite sheets were used as the building materials. Illuminated by the unique reticulate vein structures of dragonfly wings, the sheets are kept in a tensile state in purpose so as to satisfy the compatibility between the tubes and the sheets, and achieve the required stiffness in the bionic structures. By introducing bionic material and structures, three new-style space structural models were designed, such as reticulately stiffening thin-walled spherical/cylindrical/hyperbolic shell models, then they were analyzed by using ANSYS, the second model demonstrates the most satisfying performance compared with the other two ones and general three direction reticulate shell model. In order to verify its reliability and practicality, the new-style model was also evaluated against an actual engineering practice.