Examinando por Autor "Ossa, E. A."

Mostrando 1 - 7 de 7
  • No hay miniatura disponible
    Ítem
    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.
  • No hay miniatura disponible
    Ítem
    Failure analysis of a car suspension system ball joint
    (PERGAMON-ELSEVIER SCIENCE LTD, 2011-07-01) Ossa, E. A.; Palacio, C. C.; Paniagua, M. A.; Ossa, E. A.; Palacio, C. C.; Paniagua, M. A.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
  • No hay miniatura disponible
    Ítem
    Failure analysis of a car suspension system ball joint
    (PERGAMON-ELSEVIER SCIENCE LTD, 2011-07-01) Ossa, E. A.; Palacio, C. C.; Paniagua, M. A.; Universidad EAFIT. Departamento de Ciencias Básicas; Electromagnetismo Aplicado (Gema)
    [No abstract available]
  • No hay miniatura disponible
    Ítem
    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.
  • No hay miniatura disponible
    Ítem
    Nodule evolution of ductile cast iron during solidification
    (SPRINGER, 2014-04-01) Murcia, S. C.; Ossa, E. A.; Celentano, D. J.; Murcia, S. C.; Ossa, E. A.; Celentano, D. J.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    Ductile cast irons are ferrous alloys in which precipitation of graphite in the form of spherical nodules is embedded in a metal matrix to obtain ductility on the material. Despite the importance of the shape of the nodules, the models proposed to predict the solidification of ductile irons assume a perfect spherical shape during the growing process up to the final solidification of the material, which is proved not to be the case in all castings depending on the processing conditions. The influence of the process parameters on the geometry of the nodules in ductile irons was experimentally evaluated and a model to predict the evolution of nodules during solidification was proposed. The proposed model for growth predicts changes in the nodule count as well as in the nodularity based on different laws for carbon diffusion according to the solid fraction, helping to understand the trends found experimentally. © The Minerals, Metals & Materials Society and ASM International 2013.
  • Miniatura
    Ítem
    Steel cable failure analysis
    (Universidad EAFIT, 2005-12-01) Ossa, E. A.; Paniagua, M A.; University of Nottingham; Universidad EAFIT
  • No hay miniatura disponible
    Ítem
    Triaxial deformation behavior of bituminous mixes
    (ASCE-AMER SOC CIVIL ENGINEERS, 2010-02-01) Ossa, E. A.; Deshpande, V. S.; Cebon, D.; Ossa, E. A.; Deshpande, V. S.; Cebon, D.; Universidad EAFIT. Departamento de Ingeniería de Producción; Materiales de Ingeniería
    The triaxial compressive response of bituminous mixes with volume fractions of aggregate in the range 52 to 85% was investigated over a wide range stresses and strain rates. The types of loadings considered include triaxial monotonic constant stress and constant applied strain rate, as well as creep recovery, continuous cyclic, and stress pulse train loadings. The mixes with a "fully dense" aggregate skeleton were found to dilate under all loading conditions and the creep response of the mixes was dependent on both the deviatoric and hydrostatic stresses. By contrast, recovery was found to occur under zero applied deviatoric stresses with the recovery rate only dependent on the "recoverable strain" and independent of any superimposed hydrostatic stress. Continuous and pulse loading cyclic stress-controlled tests showed that the response of the mixes was governed by the mean applied deviatoric stress in the continuous cyclic tests while strain recovery was important in the pulse loading tests. A phenomenological constitutive model was proposed to fit the measured triaxial response of the bituminous mixes and shown to capture the measurements over all the triaxial stress states and loading time histories investigated here. Furthermore, the model was extended to capture the temperature dependence of the mixtures which is governed by the temperature dependence of the bitumen binder. © 2010 ASCE.