Examinando por Materia "Biological materials"

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    Effect of chemical composition and microstructure on the mechanical behavior of fish scales from Megalops Atlanticus
    (ELSEVIER SCIENCE BV, 2016-03-01) Gil-Duran, S.; Arola, D.; Ossa, E.A.; Gil-Duran, S.; Arola, D.; Ossa, E.A.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    This paper presents an experimental study of the composition, microstructure and mechanical behavior of scales from the Megalops Atlanticus (Atlantic tarpon). The microstructure and composition were evaluated by Scanning Electron Microscopy (SEM) and RAMAN spectroscopy, respectively. The mechanical properties were evaluated in uniaxial tension as a function of position along the length of the fish (head, mid-length and tail). Results showed that the scales are composed of collagen and hydroxyapatite, and these constituents are distributed within three well-defined layers from the bottom to the top of the scale. The proportion of these layers with respect to the total scale thickness varies radially. The collagen fibers are arranged in plies with different orientations and with preferred orientation in the longitudinal direction of the fish. Results from the tensile tests showed that scales from Megalops Atlanticus exhibit variations in the elastic modulus as a function of body position. Additional testing performed with and without the highly mineralized top layers of the scale revealed that the mechanical behavior is anisotropic and that the highest strength was exhibited along the fish length. Furthermore, removing the top mineralized layers resulted in an increase in the tensile strength of the scale. © 2015 Elsevier Ltd.
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    Microstructure and mechanical properties of fish scales from MegalopsAtlanticus
    (IEEE, 2013-01-01) Gil, S.; Ossa, E. A.; Gil, S.; Ossa, E. A.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    This work studies the microstructure and mechanical properties of fish scales from Tarpon fish (MegalopsAtlanticus) with cycloid scales. Mechanical properties of the scales were evaluated in uniaxial tension from three different positions along the length of the fish (head, mid-length and tail), similarly it was evaluated the effects of dehydration of the material in the mechanical properties, demonstrating an increased stiffness as a function of dehydrationas also reported Garrano et al. for CyprinusCarpio [1]. Microstructural analysis revealed that the scaleis composed by different layers associated with collagen to form a plywood like structure and a top layer associated with hydroxyapatite, as it has just been reported by several authors to different fish species [2, 3, 4]. This combination of collagen and hydroxyapatitelayers allows the fish scaleto have a high penetration resistance [5]. Microstructural analysis also reveals that the scale have a rugged circular concentric pattern on top to provide advantages associated with hydrodynamic, unlike the inner part of the scale that is in contact with the dermis which presents a smooth surface. Thus all these microstructural and mechanical characteristics are used by fish as drag reduction system, mobility and increase protection against predators, which are desirable features in engineering applications through the design of bioinspired materials.