Structural Biomimetic Models And Nanomechanics Of Membranous Wings Of Three Species Of Insects

The insect wings are principal flight organs for flight behavior. The weight of the membranous wings of an insect is just 1%–2% of the gross weight of the insect. The lifting force resulted from the insect wings is 10 times higher than that resulted from wings of plane with a same area. The membranous wings of insects are constructed with the double-decked body wall although they are very thin and very light. The membranous wings have certain hardness and can undertake the load produced by flight, such as, due to the flap flight, glides and circles during flying. Research on biological thin solid membrane has been carried out extensively since the insect wings have important structure and performance and, so, the biological thin solid membrane has become an important research field in the international high-tech new material research since 1990s and has made progress in application, such as biomimetic composite thin solid membrane application in the flapping wings of the micro flight vehicle, biomimetic coating of military equipment, biomimetic 2D composites, plastic film for agricultural production considering the environmental protection. It has broad practical application prospect and important significance in industry, military, agriculture and others. The three species of insects of hymenoptera, a species of dragonfly (Pantala flavescens Fabricius), a species of honeybee (A. c. cerana Fabricius) and a species of fly (Sarcophaga carnaria Linnaeus) were investigated. The all three species of insects have very strong flying ability. Their membranous wings are very thin and light and are constructed by wing membranes and wing veins.The morphological charaters, distribution of the wings'veins of the membranous wings of the three species of insects were examined with stereomicroscope (SZX12). The micromorphologies of the wings'veins of the membranous wings of the three species of insects were analyzed by laser scanning confocal microscope (LSOM). The morphogies of the cross sections of the membranous wings at the positions 0.3 L, 0.5 L and 0.7 L(L is the wing length) were analyzed by stereomicroscopy to compare the geometrical features of the cross sections of the membranous wings of the three species of insects. The microstructures of the cross sections of the membranous wings of the three species of insects were examined by transmission electron microscope (TEM) and their microstructural characteristics were compared.The specimens of the membranous wings of the three species (the dragonfly Pantala flavescens Fabricius, the honeybee Apis cerana cerana Fabricius and the fly Sarcophaga carnaria Linnaeus) of insects were cut using a thin sharp edge of knife and their surfaces were colorate with white colorant in order to quantificationally measuring the characteristic the three wings'surfaces for reverse engineering measurement. The membranous wings of the three speices of insect wings were measured using a reverse engineering measurement equipment, a 3D laser scanning system (Taiwan Zhitai, model LSV50). The point clouds of the surfaces of the membranous wings were obtained. The data of the point clouds were transmited into the reverse engineering software Imageware and processed for achieving the reconstruction of 3D geometric models.In order to optimize pressure-holding time and loading rate for examining the nanoindentation propertyie (elastic modulus and nano-hardness) of the membranous wings of the three species of insects, the stigma of the dragonfly Pantala flavescens Fabricius were tested in vivo under the different conditions of pressure-holding time and loading rate. It was found from the tests that 20s of the holding time and 53μN/s of the loading rate were optimal. The all nanoindentation tests of the membranous wings of the three species of insects were conduceted under these conditions. The results showed the elastic modulus and nano-hardness of three species of insect wings basically have the same changing trend, which were increased from the basal to the end of the wings and reached the maximum values at the mid-rear and then decline rapidly. It was demonstrated from comparing the nanoindentation properties that there obvious difference of the elastic modulus and nano-hardness among the membranous wings of the three species of insects. The elastic modulus and nano-hardness of the honeybee Apis cerana cerana Fabricius was the largest, those of the dragonfly Pantala flavescens Fabricius was middle, and the those of the fly Sarcophaga carnaria Linnaeus was the smallest, indicating that the elastic modulus of membranous wings of three species of insects was not disproportionate with their macro size although the costas of all three species of insect wings have the tubular structures. The nano-hardness of the membranous wings's veins of the honeybee Apis cerana cerana Fabricius was even larger than that of the the membranous wings's veins of dragonfly Pantala flavescens Fabricius. The geometrical structure of the veins would be one of the main reasons which resulted in the difference of the nano-hardness of the membranous wings's veins.The right hind wing of the dragonfly Pantala flavescens Fabricius, the right fore wing of the honeybee Apis cerana cerana Fabricius and the right wing of the fly Sarcophaga carnaria Linnaeus were analyzed by the finite element analysis software ANSYS. The concentrated force, the uniformly distributed load, ane the deformation and stress under torque were inspected. It was denmonstrated that the greater stress occurred near the base of the models for all the three insects'wings and the stress decreased gradually and the deformation increased gradually from the base to the end of the models under the concentrated force. The deformation extent of the wing model of the fly Sarcophaga carnaria Linnaeus was larger than that of the honeybee Apis cerana cerana Fabricius and dragonfly Pantala flavescens Fabricius as well.The displacement, rotating angle and stress of the all three species of insects'wing models of the veins become smaller under action of the uniform load although their distributions had certain difference, among them; the deformation was largest of the wing vein of the fly Sarcophaga carnaria Linnaeus. The displacement, rotating angle and stress of the wings'surfaces of the three species of insect wing models under the uniform surface load have the the same changing trend as under the uniform load on the vein, but the deformation and the stress were smaller. It was also shown that the wing membranes beared a smaller load and the wing veins beared the main part of the load. There were obvious differences in the structure deformation, the changing trend and the stress distribution of the three species of insect wings under torque. Also, there were some differences under uniform load and concentrated force.The above results of the geometrical morphologies, nanoindentation properties, and finite element analyis of models of the membranous wings of the three species (the dragonfly Pantala flavescens Fabricius, the honeybee Apis cerana cerana Fabricius and the fly Sarcophaga carnaria Linnaeus) of insects would provide a basis for the biomimetic design of thin solid film and 2D composite materials.