Examinando por Materia "Work study"

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    Development of as-cast dual matrix structure (DMS) ductile iron
    (ELSEVIER SCIENCE SA, 2013-03-20) Murcia, S. C.; Paniagua, M. A.; Ossa, E. A.; Murcia, S. C.; Paniagua, M. A.; Ossa, E. A.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    Ductile iron is widely used due to its low cost and higher ductility than other cast irons. There has been an increased interest during the last years in improving the strength of these materials by means of heat-treating to obtain dual matrix structures (DMS) that enhance the properties found in Austempered Ductile Irons (ADI). This work studies the fabrication of DMS ductile cast irons with martensitic and bainitic structures in the as-cast condition, reducing costs related to heat treating processing while improving the mechanical behavior of the material. Cast irons alloyed with nickel ranging from 0% up to 7% were produced in order to evaluate the effect of Ni-Mo content on the phase transformations and mechanical properties of the material. The effect of cooling rate in phase transformations and mechanical properties were studied using molds with different wall thicknesses, finding that addition of Nickel and Molybdenum improves substantially the strength of the as-cast ductile iron, making unnecessary any further heat treating according to the level of properties desired. © 2012 Elsevier B.V.
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    Natural flexible armor as an inspirationfor body armor design
    (Soc. for the Advancement of Material and Process Engineering, 2015-05-21) Alexander Ossa, E.; Alexander Ossa, E.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    Animals have developed different strategies to protect themselves from environmental and predatory threats. One of these strategies concerns with the development of natural flexible dermal armor, usually consisting of rigid and highly mineralized units (e. g. scales or osteoderms) attached by flexible collagen fibers. These kinds of arrangements have been proven to achieve high flexibility without significant reduction in strength in comparison to monolithic structures. These are in fact features extremely valued by body armor users. This work studies the mechanical characteristics of scales and osteoderms of different animals (including mammals, reptiles and fishes), in order to compare them with other characteristics of the animal itself (like length and mobility) and characteristics of their predators like geometry and composition of their teeth and strength of bite. This comparison extends our knowledge and open new ways of understanding on how to design body armor materials and structures looking into improvements on flexibility and mobility. Copyright 2015. Used by the Society of the Advancement of Material and Process Engineering with permission.