scholarly journals Influence of Fin’s Material Capabilities on the Propulsion System of Biomimetic Underwater Vehicle

2020 ◽  
Vol 27 (4) ◽  
pp. 179-185
Author(s):  
Pawel Piskur ◽  
Piotr Szymak ◽  
Zygmunt Kitowski ◽  
Leszek Flis

AbstractThe technology of Autonomous Underwater Vehicles (AUVs) is developing in two main directions focusing on improving autonomy and improving construction, especially driving and power supply systems. The new Biomimetic Underwater Vehicles (BUVs) are equipped with the innovative, energy efficient driving system consisting of artificial fins. Because these driving systems are not well developed yet, there are great possibilities to optimize them, e.g. in the field of materials. The article provides an analysis of the propulsion force of the fin as a function of the characteristics of the material from which it is made. The parameters of different materials were used for the fin design and their comparison. The material used in our research was tested in a laboratory to determine the Young’s modulus. For simplicity, the same fin geometry (the length and the height) was used for each type of fin. The Euler–Bernoulli beam theory was applied for estimation of the fluid–structure interaction. This article presents the laboratory test stand and the results of the experiments. The laboratory water tunnel was equipped with specialized sensors for force measurements and fluid–structure interaction analysis. The fin deflection is mathematically described, and the relationship between fin flexibility and the generated driving force is discussed.

Author(s):  
Chicheng Ma ◽  
Mingyu Shao ◽  
Juncheng Ma ◽  
Canchang Liu ◽  
Kunming Gao

In this work, the transversal vibration of a submerged cantilever beam is studied with a time-varying fluid domain taken into consideration. The elastic beam is modeled using the Euler–Bernoulli beam theory, and the fluid is simplified by potential fluid theory. The governing equations of this fluid-structure interaction system are obtained using the mode superposition method and Galerkin’s method. Then the influence of the time-varying fluid is investigated in detail, based on modal analysis and transient analysis. Time-frequency analysis is given for signal processing of the obtained response, as the frequencies are time-varying. The analytical results obtained in this paper show good agreement with numerical results by ANSYS and results in the previous study. This study reports a new phenomenon that changing of the fluid induces an additional nonstructural damping, which is proportional to the velocity of the depth changing of the fluid. The induced damping influences vibration of the beam significantly and must be taken into account in dynamic analysis of structures in a time-varying fluid.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
S. Zhou-Bowers ◽  
D. C. Rizos

Reduced 3D dynamic fluid-structure interaction (FSI) models are proposed in this paper based on a direct time-domain B-spline boundary element method (BEM). These models are used to simulate the motion of rigid bodies in infinite or semi-infinite fluid media in real, or near real, time. B-spline impulse response function (BIRF) techniques are used within the BEM framework to compute the response of the hydrodynamic system to transient forces. Higher-order spatial and temporal discretization is used in developing the kinematic FSI model of rigid bodies and computing its BIRFs. Hydrodynamic effects on the massless rigid body generated by an arbitrary transient acceleration of the body are computed by a mere superposition of BIRFs. Finally, the dynamic models of rigid bodies including inertia effects are generated by introducing the kinematic interaction model to the governing equation of motion and solve for the response in a time-marching scheme. Verification examples are presented and demonstrate the stability, accuracy, and efficiency of the proposed technique.


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