Microstructure and mechanical properties of sheep horn

Abstract

The sheep horn presents outstanding mechanical properties of impact resistance and energy absorption, which suits the need of the vehicle bumper design, but the mechanism behind this phenomenon is less investigated. The microstructure and mechanical properties of the sheep horn of Small Tailed Han Sheep (Ovis aries) living in northeast China were investigated in this article. The effect of sampling position and orientation of the sheep horn sheath on mechanical properties were researched by tensile and compression tests. Meanwhile, the surface morphology and microstructure of the sheep horn were observed using scanning electron microscopy (SEM). The formation mechanism of the mechanical properties of the sheep horn was investigated by biological coupling analysis. The analytical results indicated that the outstanding mechanical properties of the sheep horn are determined by configuration, structure, surface morphology and material coupling elements. These biological coupling elements make the sheep horn possess super characteristics of crashworthiness and energy absorption through the internal coupling mechanism. We suppose that these findings would make a difference in vehicle bumper design. Microsc. Res. Tech. 79:664-674, 2016. © 2016 Wiley Periodicals, Inc.

Understanding the effects of the bovine POLLED variants

“…). Horns have two main parts: a ‘dead’ keratin outer sheath and a bony inner core of ‘living’ tissue (Zhu et al ). Between the keratin sheath and bony core are several layers of tissue: the periosteum (tissue that lines the bones), subcutaneous connective tissue, dermis and epidermis (Davis et al .…”

“…Horn and scur morphology Horns of bovids are permanent, paired and symmetrical appendages that vary vastly in morphology between species and even breeds (Davis et al 2011). Horns have two main parts: a 'dead' keratin outer sheath and a bony inner core of 'living' tissue (Zhu et al 2016). Between the keratin sheath and bony core are several layers of tissue: the periosteum (tissue that lines the bones), subcutaneous connective tissue, dermis and epidermis (Davis et al 2011).…”

Morphology and nanoindentation properties of mouthparts in Cyrtotrachelus longimanus (Coleoptera: curculionidae)

“…The mechanical properties of the mouthparts are closely related to the macrostructure and microstructure (Zhu, Zhang, & Zhao, ). The mouthparts of C. longimanus adults are of typical mandibulate type, which are at the end of the snout and comprise a labrum (Lbr), a pair of mandibles (MD), a pair of maxillae (Mx), a labium (Lb), and one tongue (Tg; Figure a).…”

Finite element simulation based‐on atomic force microscopy and nanoindentation for spruce wood microstructure analysis

“…Although direct measurement techniques such as SEM and AFM can be applied to determine the morphology changes of several microstructures (Ghisleni et al, ; Kawasaki et al, ; Zhu, Zhang, & Zhao, ), they are commonly hard to perform and it takes a lot of time. Furthermore, the continuous irregular ordering of the microstructure throughout the real sample make simulation more practical; since simulations methods do not require any additional experiments to iterate the mechanical properties or boundary conditions (Samak, Fischer, & Rittel, ; Yuan, Lee, & Guilkey, ).…”

“…6 | SIMULATIONS In order to define the quantitative contribution for each microstructure of wood spruce sample, advanced characterizations of wood response under mechanical loading are needed, for instance defining the behavior of the grown tracheids microstructures direction as the lamellar microstructures with perpendicular directions. Therefore, it is required the in-situ imaging of the arrangement deformation that would properly show the performance evolution of the tested sample.Although direct measurement techniques such as SEM and AFM can be applied to determine the morphology changes of several microstructures(Ghisleni et al, 2009;Kawasaki et al, 2017;Zhu, Zhang, & Zhao, 2016), they are commonly hard to perform and it takes a lot of time. Furthermore, the continuous irregular ordering of the microstructure throughout the real sample make simulation more practical; since simulations methods do not require any additional experiments to iterate the mechanical properties or boundary conditions(Samak, Fischer, & Rittel, 2007;Yuan, Lee, & Guilkey, 2010).Then, finite element (FE) simulations of wood microstructure under compression and tension tests were carried out using ANSYS Academic Research Mechanical (Release 18.1), ANSYS Inc. A two-dimensional (2D) symmetric model was used in order to reconstruct, as much as possible, the true wood microstructure constituted of growth tracheids asFIGURE 2 AFM imaging taken in the transverse stem section for (a) a earlywood fiber and (b) a latewood fiber.…”