Examinando por Autor "Saenger, E.H."
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Ítem Digital material laboratory: Wave propagation effects in open-cell aluminium foams(Elsevier, 2012-09) Saenger, E.H.; Uribe, D.; Jänicke, R.; Ruíz, O.; Steeb, H.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEThis paper is concerned with numerical wave propagation effects in highly porous media using digitized images of aluminum foam -- Starting point is a virtual material laboratory approach -- The Aluminum foam microstructure is imaged by 3D X-ray tomography -- Effective velocities for the fluid-saturated media are derived by dynamic wave propagation simulations -- We apply a displacement-stress rotated staggered fnite-difference grid technique to solve the elastodynamic wave equation -- The used setup is similar to laboratory ultrasound measurements and the computed results are in agreement with our experimental data -- Theoretical investigations allow to quantify the influence of the interaction of foam and fluid during wave propagation – Together with simulations using an artificial dense foam we are able to determine the tortuosity of aluminum foamÍtem Geometric and numerical modeling for porous media wave propagation(2014) Uribe, D.; Osorno, M.; Steeb, H.; Saenger, E.H.; Ruíz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEDetermining hydro-mechanical properties of porous materials present a challenge because they exhibit a more complex behaviour than their continuous counterparts -- The geometrical factors such as pore shape, length scale and occupancy play a definite role in the materials characterization -- On the other hand, computational mechanics calculations for porous materials face an intractable amount of data -- To overcome these difficulties, this investigation propose a workflow (Image segmentation, surface triangulation and parametric surface fitting) to model porous materials (starting from a high-resolution industrial micro-CT scan) and transits across different geometrical data (voxel data, cross cut contours, triangular shells and parametric quadrangular patches) for the different stages in the computational mechanics simulations -- We successfully apply the proposed workflow in aluminum foam -- The various data formats allow the calculation of the tortuosity value of the material by using viscoelastic wave propagation simulations and poroelastic investigations -- Future work includes applications for the geometrical model such as boundary elements and iso-geometrical analysis, for the calculation of material propertiesÍtem Numerical estimation of Carbonate properties using a digital rock physics workflow(2014) Osorno, M.; Uribe, D.; Saenger, E.H.; Madonna, C.; Steeb, H.; Ruíz, Ó.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEDigital rock physics combines modern imaging with advanced numerical simulations to analyze the physical properties of rocks -- In this paper we suggest a special segmentation procedure which is applied to a carbonate rock from Switzerland -- Starting point is a CTscan of a specimen of Hauptmuschelkalk -- The first step applied to the raw image data is a nonlocal mean filter -- We then apply different thresholds to identify pores and solid phases -- Because we are aware of a nonneglectable amount of unresolved microporosity we also define intermediate phases -- Based on this segmentation determine porositydependent values for the pwave velocity and for the permeability -- The porosity measured in the laboratory is then used to compare our numerical data with experimental data -- We observe a good agreement -- Future work includes an analytic validation to the numerical results of the pwave velocity upper bound, employing different filters for the image segmentation and using data with higher resolutionÍtem Numerical estimation of carbonate properties using a digital rock physics workflow(EAGE Publishing BV, 2014-01-01) Osorno, M.; Uribe, D.; Saenger, E.H.; Madonna, C.; Steeb, H.; Ruiz, O.; Universidad EAFIT. Departamento de Ingeniería Mecánica; Laboratorio CAD/CAM/CAEDigital rock physics combines modern imaging with advanced numerical simulations to analyze the physical properties of rocks. In this paper we suggest a special segmentation procedure which is applied to a carbonate rock from Switzerland. Starting point is a CT-scan of a specimen of Hauptmuschelkalk. The first step applied to the raw image data is a non-local mean filter. We then apply different thresholds to identify pores and solid phases. Because we are aware of a non-neglectable amount of unresolved microporosity we also define intermediate phases. Based on this segmentation determine porosity-dependent values for the p-wave velocity and for the permeability. The porosity measured in the laboratory is then used to compare our numerical data with experimental data. We observe a good agreement. Future work includes an analytic validation to the numerical results of the p-wave velocity upper bound, employing different filters for the image segmentation and using data with higher resolution.