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

Firstly, the high resolution pictures of dragonfly wings from sample tests were studied thoroughly, and the unique feature of the reticulate vein distribution and the variation of the vein sizes and the grid shapes in different zones were figured out;then several computational models based on a dragonfly wing were established by using ANSYS, and beam 189 and shell 93 elements were used respectively in modeling of the veins and the membrane so as to ensure the compatibility between the veins and the membrane at a deformed state;these models subject to uniform loading cases were analyzed respectively so as to explore the unique performances of the wing structure, furthermore, through eigenvalue spectrum analyses of these models, the special role of the pterostigma in eliminating or suppressing the wing quivering effect was also evaluated. In numerical analyses, the wing models with or without membrane were studied, respectively, and the results from different models were compared, some significant conclusions were drown that the membrane will play an important role in some loading cases, and the magnitude of tensile stress in membrane has a great effect on the stiffness of the wing structure.Secondly, considering the complexity of the reticulate vein structure, it is impractical to copy the complete wing structure in bionic structural design due to special technical requirements and expensive cost, so it is significant in engineering application to simplify the reticulate vein structure moderately while try to keep its superiority in structural performance. Some models were designed where the unique tetragon and hexagon grids borrowed from the wing structure were used as the basic elements, these models were analyzed numerically, it is shown that the model consisting of tetragon grids is much stiffer than that consisting of hexagon grids, while, more material is used in the first model;crinkling models based on tetragon grids or arched models consisting of hexagon grids become more stiffer than flat ones;hybrid models consisting of tetragon grids and hexagon grids can realize a proper balance between material saving and stiffness improving.Finally, three new-style reticulately stiffening thin-wall cantilever models with different grid forms and grids arrangement were proposed, and their structural performances were studied by means of linear analysis, geometrically nonlinear analysis, dynamic analysis and buckling analysis, respectively. Based on the results, an optimization new-style reticulately stiffening thin-wall cantilever model was achieved, furthermore, another two new-style deployable reticulately stiffening thin-wall cantilever models evolved from this optimized model, and static structures become vivid, and a higher level of bionic modeling of dragonfly wings was realized.