Examinando por Materia "Parameterized"

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    Ítem
    Acoustic displacement tetrahedra developed using the IET rules
    (PERGAMON-ELSEVIER SCIENCE LTD, 2010-09-01) Correa, S.; Militello, C.; Recuero, M.; Universidad EAFIT. Departamento de Ingeniería de Diseño; Ingeniería de Diseño (GRID)
    A four node, displacement based, acoustic element is developed. In order to avoid spurious rotational modes, a higher order stiffness is introduced. The higher order stiffness is developed from an incompatible strain field which computes element volume changes under nodal rotational displacements fields. The higher order strain satisfies the IET requirements, non affecting convergence. The higher order stiffness is modulated, element by element, with a factor. Thus, the displacement based formulation is capable of placing the spurious rotational modes over the range of physical compressional modes that can be accurately captured by the mesh. © 2010 Elsevier Ltd. All rights reserved.
  • No hay miniatura disponible
    Ítem
    Acoustic displacement tetrahedra developed using the IET rules
    (PERGAMON-ELSEVIER SCIENCE LTD, 2010-09-01) Correa, S.; Militello, C.; Recuero, M.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Bioingeniería GIB (CES – EAFIT)
    A four node, displacement based, acoustic element is developed. In order to avoid spurious rotational modes, a higher order stiffness is introduced. The higher order stiffness is developed from an incompatible strain field which computes element volume changes under nodal rotational displacements fields. The higher order strain satisfies the IET requirements, non affecting convergence. The higher order stiffness is modulated, element by element, with a factor. Thus, the displacement based formulation is capable of placing the spurious rotational modes over the range of physical compressional modes that can be accurately captured by the mesh. © 2010 Elsevier Ltd. All rights reserved.
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    Ítem
    Speckle decorrelation influence on measurements quality in vortex metrology
    (ELSEVIER SCIENCE BV, 2012-10-01) Angel-Toro, Luciano; Sierra-Sosa, Daniel; Tebaldi, Myrian; Bolognini, Nestor; Universidad EAFIT. Departamento de Ciencias Básicas; Óptica Aplicada
    We study speckle decorrelation effects in connection with conventional vortex metrology techniques. Our proposal is based on processing speckled images recorded by using two different experimental set-ups. In both schemes two laterally displaced patterns are generated: one scheme allows for obtaining undecorrelated speckle distributions and the other for decorrelated ones. Vortex networks associated with speckle patterns are analyzed by employing the usual tools developed for vortex metrology. For each recorded image, a 2D pseudo-phase map is generated on the basis of the Reisz transform. Then the vortices are located, and parameterized in terms of their topological charge, eccentricity, vorticity and angles between the zero crossing lines from the real and the imaginary parts of the analytical signal. After tracking the homologous vortices onto the maps, the histograms corresponding to the coordinate displacements are analyzed. We show that histograms interpretation is prone to failure due to its high sensitivity to decorrelation. Experimental evidences are presented to support the restrictions imposed by decorrelation of actual speckles due to uniform in-plane displacements. © 2012 Elsevier B.V. All rights reserved.