Creatures with longer bodies in nature like snakes and eels moving in water commonly generate a large swaying of their bodies or tails,with the purpose of producing significant frictions and collisions between body and fluid to provide the power of con-secutive forward force.This swaying can be idealized by considering oscillations of a soft beam immersed in water when waves of vibration travel down at a constant speed.The present study employs a kind of large deformations induced by nonlinear vibrations of a soft pipe conveying fluid to design an underwater bio-inspired snake robot that consists of a rigid head and a soft tail.When the head is fixed,experiments show that a second mode vibration of the tail in water occurs as the internal flow velocity is beyond a critical value.Then the corresponding theoretical model based on the absolute nodal coordinate formulation(ANCF)is established to describe nonlinear vibrations of the tail.As the head is free,the theoretical modeling is combined with the computational fluid dynamics(CFD)analysis to construct a fluid-structure interaction(FSI)simulation model.The swimming speed and swaying shape of the snake robot are obtained through the FSI sim-ulation model.They are in good agreement with experimental results.Most importantly,it is demonstrated that the propulsion speed can be improved by 21％for the robot with vibrations of the tail compared with that without oscillations in the pure jet mode.This research provides a new thought to design driving devices by using nonlinear flow-induced vibrations.

Huliang DAI;Yixiang HE;Kun ZHOU;Zerui PENG;Lin WANG;P.HAGEDORN

Department of Mechanics,Huazhong University of Science and Technology,Wuhan 430074,China;Hubei Key Laboratory for Engineering Structural Analysis and Safety Assessment,Wuhan 430074,China;Department of Mechanical Engineering,Technische Universit?t Darmstadt,Darmstadt 64293,Germany;State Key Laboratory of Structural Analysis for Industrial Equipment,Dalian University of Technology,Dalian 116024,Liaoning Province,China

应用数学和力学（英文版）

[1]Huliang DAI;Yixiang HE;Kun ZHOU;Zerui PENG;Lin WANG;P.HAGEDORN-.Utilization of nonlinear vibrations of soft pipe conveying fluid for driving underwater bio-inspired robot)[J].应用数学和力学（英文版）,2022(07):1109-1124

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