Research On Structure Design And Simulation For The Bionic Set Inspired By Undulatory Dorsal Fin

Enlightened by the high efficiency and celerity of the fish propulsion in nature, the bionic study of fish propulsion has become a hot topic in the technology of underwater propulsion. During millions of years' evolution, Gymnarchus Niloticus has gained a unique physique and special movement form, it can adapt to the underwater environment very well. While swimming, G.niloticus keeps its slim body straight, and through the movement of the undulatory dorsal fin can it move freely.In this paper, the structure design and simulation of a bionic set, which could imitate the movement of the undulatory dorsal fin of Gymnarchus Niloticus, has been introduced. By observing the movement of G.niloticus, this paper analyses the structure and propulsive mechanism of the undulatory dorsal fin, and then gives a simplified kinematic model of it. According to the simplified kinematic model, the bionic set of the undulatory dorsal fin has been designed in a three-dimensional CAD software. With the FEA method in a CAE software, we analyze the structure-static feature and mode-oscillation state of the key parts in the bionic set. At last, the movement of the set has been simulated, and then with the fabrication of real bionic set, a test on the propulsive effect in still water has been shown.The results of test show that, the bionic set designed according to the undulatory propulsive mechanism have achieved the expected movement caused by the ndulatory propulsive force, they also prove that the design project is feasible. On the other hand, the analysis on the results also promoted the research of the undulatory propulsive mechanism.