Investigating the Propulsive Efficiency of Bio-Inspired Fish-like Elastic Caudal Fin through Dynamic Analysis and Experimental Validation

The present work focuses on the dynamic analysis of bio-inspired fish-like robotic fins in order to evaluate their propulsive efficiency. This study relates the effect of the main factors on which this efficiency depends, particularly materialsand stiffness in a typical biomimetic range. Numerical and experimental modal analysis techniques are employed to examine the vibrational properties of different fins. This analysis is essential to characterize the elastic materials and understand how the respective stiffness levels affect the dynamic behavior of the fin. A numerical analysis is then conducted using ananalytical model that simulates the coupled dynamics between the fluid and the elastic fin. This model takes into account the two-ways interaction between the hydrodynamic forces and elastic deformations of the fin, allowing a detailed evaluation of propulsive efficiency parameters. Key performance indicators, such as elastic deformation, thrust, and efficiency, are calculated and analyzed in relation to changes in materials and stiffness. Hydrodynamic tank experiments are ongoing todirectly measure the performance of the robotic fins, comparing the experimental data with the predictions of the analytical model. This validation phase is critical to confirm the accuracy of the model and to further refine the predictions regarding propulsive efficiency. The results of this paper provide valuable insights for the future design of underwater robots, with potential applications in areas such as marine exploration, environmental monitoring, and bioinspired robotics