| Abstract [eng] |
This final project focused on the application of bionics in aviation, and the use of micro aerial vehicles for civil and military applications. The literature review discussed the anatomy of the dragonfly body and wing, and the protein resilin in the wing that adds elasticity to it. The materials and properties of the veins and membrane were also described. The sections on dragonfly biology, the physics of dragonfly flight and numerical models of the dragonfly wing discussed research carried out by other scientists on aspects of the dragonfly wing that were investigated in this study. The theoretical part of this project described the aerodynamic formulae that can be used to explain dragonfly flight, the Navier-Stokes equations that explain the flow of liquids and gases, the methods and algorithms used to construct a geometric model of the wing's morphology, the Finite Element Method, deformation and the interaction between a fluid and a deformable body. One of the studies carried out in this project is a scanning electron microscope study on the forewing of the dragonfly Aeshna Cyanea. During this study, various areas of the wing were observed: the root, the mechanosensors, the leading-edge vein and its serrated structure, the nodus, and various veins. The project led to the development of a mathematical and numerical model of the dragonfly forewing. Static analysis of the wing model was carried out by applying the properties of chitin to the veins and the properties of the membrane found in the literature to the membrane. The wing root was rigidly fixed and the wing leading-edge vein was loaded with a force of 6,7 N from the nodus towards the wing tip. The analysis showed that the maximum displacements were 0,66 mm and the maximum stresses were 6,98 MPa. The next study was carried out to determine the first resonant frequency of the wing by two tests: impact, and forced excitation. Two dragonfly wings of the same species were tested. The results of the two tests were similar, with the first wing having a first resonant frequency of 81,57 Hz by the impact method and 78,67 Hz by the forced excitation method, while the second wing had 101,57 Hz and 96,15 Hz respectively. In this study, it was found that the first resonant frequency of one wing is not representative of the overall performance of the species, but a reasonably clear range of frequencies can be obtained depending on the wing area. The last study of this project was to investigate the force generated by a dragonfly during flight and its variation with time (with the change of the flight cycle). The study shows that the mass of the dragonfly has no direct influence on the force generated, as the dragonfly with the lowest mass generates the highest force and the dragonfly with the second highest mass generates the second highest force. It can also be argued that mechanical damage to the wing has a significant effect on the magnitude of the force generated by the dragonfly during flight. This final project aimed to investigate the different mechanical properties of the dragonfly wing and its possible application for the development of micro aerial vehicles in the future. |
