title: Dynamic impact testing of hedgehog spines using a dual-arm crash pendulum.
abstract: Hedgehog spines are a potential model for impact resistant structures and material. While previous studies have examined static mechanical properties of individual spines, actual collision tests on spines analogous to those observed in the wild have not previously been investigated. In this study, samples of roughly 130 keratin spines were mounted vertically in thin substrates to mimic the natural spine layout on hedgehogs. A weighted crash pendulum was employed to induce and measure the effects of repeated collisions against samples, with the aim to evaluate the influence of various parameters including humidity effect, impact energy, and substrate hardness. Results reveal that softer samples-due to humidity conditioning and/or substrate material used-exhibit greater durability over multiple impacts, while the more rigid samples exhibit greater energy absorption performance at the expense of durability. This trend is exaggerated during high-energy collisions. Comparison of the results to baseline tests with industry standard impact absorbing foam, wherein the spines exhibit similar energy absorption, verifies the dynamic impact absorption capabilities of hedgehog spines and their candidacy as a structural model for engineered impact technology.
authors.affiliation: Department of Physics, Science Technology Entrepreneurship Master׳s Program, Case Western Reserve University, Cleveland, OH 44106, USA.
authors.forename: Nathan B
authors.initials: NB
authors.lastname: Swift
authors.affiliation: Department of Biology, Integrated Bioscience PhD Program, The University of Akron, Akron, OH 44325, USA.
authors.forename: Bor-Kai
authors.initials: BK
authors.lastname: Hsiung
authors.affiliation: Department of Biology, Integrated Bioscience PhD Program, The University of Akron, Akron, OH 44325, USA.
authors.forename: Emily B
authors.initials: EB
authors.lastname: Kennedy
authors.affiliation: Department of Mechanical Engineering, The University of Akron, Akron, OH 44325, USA. Electronic address: ktan@uakron.edu.
authors.forename: Kwek-Tze
authors.initials: KT
authors.lastname: Tan
mesh_terms: D000825:Animal Structures / Q000502:physiology*; D000818:Animals; D001696:Biomechanical Phenomena; D006244:Hardness; D006364:Hedgehogs
keywords: Biomimicry; Energy absorption; Hedgehog spines; Humidity; Impact pendulum; Keratin