Boni, ClaudioReis, Pedro M.Royer-Carfagni, Gianni2022-10-102022-10-102022-10-102022-10-0110.1016/j.eml.2022.101853https://infoscience.epfl.ch/handle/20.500.14299/191361WOS:000860296900003Many aquatic animals propel themselves by flapping their tails. Leveraging a recently proposed snapping cantilever beam based on the concept of flexural tensegrity, we propose a bio-inspired propulsion device. The design comprises a segmental beam with hollow voussoirs in unilateral contact along tailor-shaped surfaces, held together by a prestressed internal cable. Prescribing relative periodic rotation to a pair of consecutive control segments of the structured beam produces multi-articulated sequential snapping of all joints. We built a series of prototypes and performed precision experimental tests in water to characterize their propulsive capacity. A parametric study was carried out to characterize the dependence of the thrust produced by the oscillating tail on the following factors: number of segments, shape of the internal cavities dictating the cantilever curvature, and mobility constraint of a fin appended at the end of the tail. The results provide a proof of concept that our design for a snapping structured beam can be used as a propulsive device. We further demonstrate the feasibility of this propulsion unit to propel a toy boat in a water basin. (C) 2022 Elsevier Ltd. All rights reserved.Engineering, MechanicalMaterials Science, MultidisciplinaryMechanicsEngineeringMaterials Scienceflexural tensegritypropulsion systemsnap-through instabilitykinetic structuresbi-stable mechanismfluid interactionmorphologyfishtext::journal::journal article::research article