Study On Bionic Wrinkled Ring-web Shells Based On Dragonfly Wings

The significant part of architecture bionics as it is, structural bionic applies the internal structural characteristics of living beings, which has evolved since billions of years ago, to the structure design. At present, researches in China have shown that the wrinkled structure enhances the structural rigidity of dragonfly wings. The co-working between veins and the membranes allows the wings to resist all sorts of loads during the flight. This paper studies on the application of bionic principles of dragonfly wings to ring-web shell structure.In this paper, the steel gridding imitates the veins while the composite board imitates the membrane, which forms the co-working structure system. Based on the Ansys11.0 software, the shells are imitated by 8-node unit"shell 93"while the steel bars are imitated by 3-node unit"beam 189", which meet the boundary harmony well. Considered the geometric nonlinear deformation of the shells, the vertical displacements of the ring-web shell structure are analyzed and compared, in different cases of materials, thickness of the shells, span ratios and the wrinkled degrees. It proves that the rigidity of the gridding with shells is larger than the one without shells. Among the different composites, carbon fiber/epikote composite contributes most to the structural rigidity; To some degree, the stress stiffness of the shells strengthened when the thickness of the shells; As different span ratio increases, the rigidity will grow while it needs more materials and the stress stiffness will weaken. Considered all the factors, a reasonable span ratio is chosen; Wrinkled structure enhances the rigidity of the dragonfly wings, and the results shows that modulation of the wrinkled degree can decrease the vertical displacement of the vertex, homogenize and reduce the vertical displacements of other nodes. That means the wrinkled structure strengthens the rigidity. Albeit, when the wrinkled degree is excessive, the displacement of the vertex is upward, and the relative displacements between nodes enhance, which deteriorate the node structures. At last, based on the analysis above, the new-style wrinkled ring-web shell structure is proposed. The result shows that the new structure can perform the wrinkled principle and the co-working rules between veins and membranes. Furthermore, the structure is light and good-looking.