Using a modified Monte Carlo method, the authors have investigated the variation of diffusion coe... more Using a modified Monte Carlo method, the authors have investigated the variation of diffusion coefficient with departure from stoichiometry in pyrrhonist. Fe-S. Four different site-exclusion models were chosen to describe the interaction between vacancies.Comparison of the calculated results with available tracer diffusion data suggest that below the Néel temperature(1) vacancy-vacancy interaction extends to fifth nearest neighbours, and (2) the direct
This paper reports on an investigation of the compressive properties of Corevo® foam.
Corevo® foa... more This paper reports on an investigation of the compressive properties of Corevo® foam. Corevo® foam is a cellular metal manufactured by the infiltration casting of salt dough with aluminium. Corevo® foam samples with different porosities are tested by using quasi-static compression loading. Their mechanical properties (i.e.: effective Young’s modulus, Poisson’s ratio, initial yield stress and material yield stress) are then compared to reveal the importance of the density difference. In addition, three-dimensional finite element analysis is performed on models generated from micro-computed tomography (μCT). The results of two different pore sizes are obtained and compared in the scope of this work. These numerical results are verified by comparison with the experimental analysis. Sound agreement is found. Numerical analysis in this work also includes the investigation of the mechanical material anisotropy and plastic deformation.
Description The Lattice Monte Carlo method is a computationally intensive approach towards the st... more Description The Lattice Monte Carlo method is a computationally intensive approach towards the study of thermal material properties. The Lattice Monte Carlo method has previously been used in the area of mass diffusion, and has more recently been applied towards the analysis of thermal diffusion in materials. Whilst previous studies have focused on two-phase material consisting of component material and pore geometry only, this study applies the Lattice Monte Carlo method towards the investigation of three-phase Metallic ...
ABSTRACT This work addresses the effective thermal conductivity of cellular metals. Analytical re... more ABSTRACT This work addresses the effective thermal conductivity of cellular metals. Analytical relations for upper and lower bonds are evaluated. Formulae for effective conductivities are developed for an accurate estimation. In addition, extensive thermal Lattice Monte Carlo analyses are performed on a range of geometries. Next to simplified model structures, real geometries are addressed that exhibit closed (thick-walled structures), interconnected (open-cell structures) or both types (thin-walled structures) of porosity. To this end, calculation models of the real materials were directly based on computed tomography (CT) data in order to achieve a high level of geometrical accuracy.
ABSTRACT This paper addresses Knudsen diffusion in cellular metals. Knudsen diffusivities for air... more ABSTRACT This paper addresses Knudsen diffusion in cellular metals. Knudsen diffusivities for air at room temperature are calculated for a representative cross-section of the different types of cellular materials: a sintered fibre structure, a lotus-type porous metal, a sintered metallic hollow sphere structure and a M-Pore® aluminium foam. The geometrical discretization of the calculation models is based on computed tomography data. This approach is essential in order to address the complex geometries of cellular metals. In total, seven calculation models with porosities ranging from 0.26 to 0.92 are considered. In addition, anisotropy is investigated by determining directional components of the Knudsen diffusivity.
end, expanded perlite particles are combined with an aluminium alloy matrix. This enables close c... more end, expanded perlite particles are combined with an aluminium alloy matrix. This enables close control of geometry at a relatively low production cost. The mechanical properties of the material are studied using finite element analysis. Numerical calculation models are generated directly from micro-computed tomography in order to capture their complex internal geometry. For verification purposes, numerical results are compared with experimental measurements of similar samples where available. But in contrast to experimental testing the numerical analysis is non-destructive and hence allows the repeated testing of samples in multiple loading directions. Thus, material anisotropy can be investigated for the first time. To this end, the quasi-elastic gradient, the 1% offset yield stress and the plateau stresses are obtained from virtual compression tests in three perpendicular directions (one coincides with the casting direction). Results indicate a weak anisotropy of the mechanical properties.
Using a modified Monte Carlo method, the authors have investigated the variation of diffusion coe... more Using a modified Monte Carlo method, the authors have investigated the variation of diffusion coefficient with departure from stoichiometry in pyrrhonist. Fe-S. Four different site-exclusion models were chosen to describe the interaction between vacancies.Comparison of the calculated results with available tracer diffusion data suggest that below the Néel temperature(1) vacancy-vacancy interaction extends to fifth nearest neighbours, and (2) the direct
This paper reports on an investigation of the compressive properties of Corevo® foam.
Corevo® foa... more This paper reports on an investigation of the compressive properties of Corevo® foam. Corevo® foam is a cellular metal manufactured by the infiltration casting of salt dough with aluminium. Corevo® foam samples with different porosities are tested by using quasi-static compression loading. Their mechanical properties (i.e.: effective Young’s modulus, Poisson’s ratio, initial yield stress and material yield stress) are then compared to reveal the importance of the density difference. In addition, three-dimensional finite element analysis is performed on models generated from micro-computed tomography (μCT). The results of two different pore sizes are obtained and compared in the scope of this work. These numerical results are verified by comparison with the experimental analysis. Sound agreement is found. Numerical analysis in this work also includes the investigation of the mechanical material anisotropy and plastic deformation.
Description The Lattice Monte Carlo method is a computationally intensive approach towards the st... more Description The Lattice Monte Carlo method is a computationally intensive approach towards the study of thermal material properties. The Lattice Monte Carlo method has previously been used in the area of mass diffusion, and has more recently been applied towards the analysis of thermal diffusion in materials. Whilst previous studies have focused on two-phase material consisting of component material and pore geometry only, this study applies the Lattice Monte Carlo method towards the investigation of three-phase Metallic ...
ABSTRACT This work addresses the effective thermal conductivity of cellular metals. Analytical re... more ABSTRACT This work addresses the effective thermal conductivity of cellular metals. Analytical relations for upper and lower bonds are evaluated. Formulae for effective conductivities are developed for an accurate estimation. In addition, extensive thermal Lattice Monte Carlo analyses are performed on a range of geometries. Next to simplified model structures, real geometries are addressed that exhibit closed (thick-walled structures), interconnected (open-cell structures) or both types (thin-walled structures) of porosity. To this end, calculation models of the real materials were directly based on computed tomography (CT) data in order to achieve a high level of geometrical accuracy.
ABSTRACT This paper addresses Knudsen diffusion in cellular metals. Knudsen diffusivities for air... more ABSTRACT This paper addresses Knudsen diffusion in cellular metals. Knudsen diffusivities for air at room temperature are calculated for a representative cross-section of the different types of cellular materials: a sintered fibre structure, a lotus-type porous metal, a sintered metallic hollow sphere structure and a M-Pore® aluminium foam. The geometrical discretization of the calculation models is based on computed tomography data. This approach is essential in order to address the complex geometries of cellular metals. In total, seven calculation models with porosities ranging from 0.26 to 0.92 are considered. In addition, anisotropy is investigated by determining directional components of the Knudsen diffusivity.
end, expanded perlite particles are combined with an aluminium alloy matrix. This enables close c... more end, expanded perlite particles are combined with an aluminium alloy matrix. This enables close control of geometry at a relatively low production cost. The mechanical properties of the material are studied using finite element analysis. Numerical calculation models are generated directly from micro-computed tomography in order to capture their complex internal geometry. For verification purposes, numerical results are compared with experimental measurements of similar samples where available. But in contrast to experimental testing the numerical analysis is non-destructive and hence allows the repeated testing of samples in multiple loading directions. Thus, material anisotropy can be investigated for the first time. To this end, the quasi-elastic gradient, the 1% offset yield stress and the plateau stresses are obtained from virtual compression tests in three perpendicular directions (one coincides with the casting direction). Results indicate a weak anisotropy of the mechanical properties.
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Papers by G. Murch
Corevo® foam is a cellular metal manufactured by the infiltration casting of salt dough with
aluminium. Corevo® foam samples with different porosities are tested by using quasi-static
compression loading. Their mechanical properties (i.e.: effective Young’s modulus, Poisson’s ratio,
initial yield stress and material yield stress) are then compared to reveal the importance of the
density difference. In addition, three-dimensional finite element analysis is performed on models
generated from micro-computed tomography (μCT). The results of two different pore sizes are
obtained and compared in the scope of this work. These numerical results are verified by
comparison with the experimental analysis. Sound agreement is found. Numerical analysis in this
work also includes the investigation of the mechanical material anisotropy and plastic deformation.
of geometry at a relatively low production cost. The mechanical properties of the material are studied
using finite element analysis. Numerical calculation models are generated directly from
micro-computed tomography in order to capture their complex internal geometry. For verification purposes,
numerical results are compared with experimental measurements of similar samples where available.
But in contrast to experimental testing the numerical analysis is non-destructive and hence allows
the repeated testing of samples in multiple loading directions. Thus, material anisotropy can be investigated
for the first time. To this end, the quasi-elastic gradient, the 1% offset yield stress and the plateau
stresses are obtained from virtual compression tests in three perpendicular directions (one coincides
with the casting direction). Results indicate a weak anisotropy of the mechanical properties.
Corevo® foam is a cellular metal manufactured by the infiltration casting of salt dough with
aluminium. Corevo® foam samples with different porosities are tested by using quasi-static
compression loading. Their mechanical properties (i.e.: effective Young’s modulus, Poisson’s ratio,
initial yield stress and material yield stress) are then compared to reveal the importance of the
density difference. In addition, three-dimensional finite element analysis is performed on models
generated from micro-computed tomography (μCT). The results of two different pore sizes are
obtained and compared in the scope of this work. These numerical results are verified by
comparison with the experimental analysis. Sound agreement is found. Numerical analysis in this
work also includes the investigation of the mechanical material anisotropy and plastic deformation.
of geometry at a relatively low production cost. The mechanical properties of the material are studied
using finite element analysis. Numerical calculation models are generated directly from
micro-computed tomography in order to capture their complex internal geometry. For verification purposes,
numerical results are compared with experimental measurements of similar samples where available.
But in contrast to experimental testing the numerical analysis is non-destructive and hence allows
the repeated testing of samples in multiple loading directions. Thus, material anisotropy can be investigated
for the first time. To this end, the quasi-elastic gradient, the 1% offset yield stress and the plateau
stresses are obtained from virtual compression tests in three perpendicular directions (one coincides
with the casting direction). Results indicate a weak anisotropy of the mechanical properties.