Flexural-tensegrity snapping tails for bio-inspired propulsion in fluids. (October 2022)

• Record Type: Journal Article
• Authors: Boni, Claudio; Reis, Pedro M.; Royer-Carfagni, Gianni
• Is Part Of: Extreme mechanics letters. Volume 56(2022)
• Publication Date: 2022-10
• Subjects: Flexural tensegrity -- Propulsion system -- Snap-through instability -- Kinetic structures -- Bi-stable mechanism -- Fluid interaction; Mechanics -- Periodicals; Mechanics, Applied -- Periodicals; Mechanics; Electronic journals; Periodicals; 531.05
• DOI: 10.1016/j.eml.2022.101853
• Languages: English
• ISSNs: 2352-4316

Abstract

Abstract: Many 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.