title: The natural armors of fish: A comparison of the lamination pattern and structure of scales.
abstract: Fish scales exhibit a unique balance of flexibility, strength and toughness, which is essential to provide protection without encumbering locomotion. Although the mechanical behavior and structure of this natural armor are of recent interest, a comparison of these qualities from scales of different fish species has not been reported. In this investigation the armor of fish with different locomotion, size and protection needs were analyzed. Scales from the Arapaima gigas, the tarpon (Megalops atlanticus) and the carp (Cyprinus carpio) were compared in terms of the stacking sequence of individual plies and their microstructure. The scales were also compared with respect to anatomical position to distinguish site-specific functional differences. Results show that the lamination sequence of plies for the carp and tarpon exhibit a Bouligand structure with relative rotation of 75° between consecutive plies. The arapaima scales exhibit a cross-ply structure, with 90° rotation between adjacent plies. In addition, results indicate that the volume fraction of reinforcement, the number of plies and the variations in thickness with anatomical position are unique amongst the three fish. These characteristics should be considered in evaluations focused on the mechanical behavior.
authors.affiliation: Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA.
authors.forename: Sandra
authors.initials: S
authors.lastname: Murcia
authors.affiliation: Molecular Analysis Facility (MAF), MolES, University of Washington, Seattle, WA, USA.
authors.forename: Ellen
authors.initials: E
authors.lastname: Lavoie
authors.affiliation: Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Tim
authors.initials: T
authors.lastname: Linley
authors.affiliation: Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA, USA.
authors.forename: Arun
authors.initials: A
authors.lastname: Devaraj
authors.affiliation: Production Engineering Department, School of Engineering, Universidad Eafit, Medellín, Colombia.
authors.forename: E Alex
authors.initials: EA
authors.lastname: Ossa
authors.affiliation: Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA. Electronic address: darola@uw.edu.
authors.forename: D
authors.initials: D
authors.lastname: Arola
mesh_terms: D000075342:Animal Scales / Q000502:physiology* / Q000648:ultrastructure; D000818:Animals; D005399:Fishes
keywords: Armor; Collagen; Fish scales; Nature; Stacking sequence