The Experts below are selected from a list of 128541 Experts worldwide ranked by ideXlab platform
C K Lee - One of the best experts on this subject based on the ideXlab platform.
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automatic metric 3d surface mesh generation using subdivision surface Geometrical Model part 2 mesh generation algorithm and examples
International Journal for Numerical Methods in Engineering, 2003Co-Authors: C K LeeAbstract:In this paper, a new metric advancing front surface mesh generation scheme is suggested. This new surface mesh generator is based on a new Geometrical Model employing the interpolating subdivision surface concept. The target surfaces to be meshed are represented implicitly by interpolating subdivision surfaces which allow the presence of various sharp and discontinuous features in the underlying Geometrical Model. While the main generation steps of the new generator are based on a robust metric surface triangulation kernel developed previously, a number of specially designed algorithms are developed in order to combine the existing metric advancing front algorithm with the new Geometrical Model. As a result, the application areas of the new mesh generator are largely extended and can be used to handle problems involving extensive changes in domain geometry. Numerical experience indicates that, by using the proposed mesh generation scheme, high quality surface meshes with rapid varying element size and anisotropic characteristics can be generated in a short time by using a low-end PC. Finally, by using the pseudo-curvature element-size controlling metric to impose the curvature element-size requirement in an implicit manner, the new mesh generation procedure can also generate finite element meshes with high fidelity to approximate the target surfaces accurately. Copyright © 2003 John Wiley & Sons, Ltd.
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Automatic metric 3D surface mesh generation using subdivision surface Geometrical Model. Part 1: Construction of underlying Geometrical Model
International Journal for Numerical Methods in Engineering, 2003Co-Authors: C K LeeAbstract:Summary This paper proposes a new automatic mesh generation algorithm for 3D surface mesh generation. The algorithm is base d on the metric specification approach and can generate anisotropic meshes on 3D surfaces. It is based on a new Geometrical Model using the interpolating subdivision surface concept. By using the subdivision surface concept, the new mesh generator can generate finite element meshes to Model a wide range of surfaces which may contain sharp features such as cusp and crease lines. When comparing with other algorithms which use analytical surface patches as the underlying Geometrical Model, the new mesh generation scheme can be used in applications such as large deformation or crack analyses in which the domains to be gridded are not well defined or involve changing boundary. The presentation of the work is divided into two parts. In Part I, i.e. the present paper, a detailed description of the underlying Geometrical Model used will be given while in Part II, attentions will be focused on the mesh generation algorithms and the performance of the mesh generator.
R Budaca - One of the best experts on this subject based on the ideXlab platform.
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harmonic oscillator potential with a sextic anharmonicity in the prolate γ rigid collective Geometrical Model
Physics Letters B, 2014Co-Authors: R BudacaAbstract:Abstract An analytical expression for the energy spectrum of the ground and β bands was obtained through the JWKB approximation in the axially symmetric γ -rigid regime of the Bohr–Mottelson Hamiltonian with an oscillator potential and a sextic anharmonicity in the β shape variable. Due to the scaling property of the problem, the resulting energy depends up to an overall multiplicative constant on a single parameter. Studying the behavior of the energy spectrum as a function of the free parameter, one establishes the present Model's place among other prolate γ -rigid Models and in the more general extent of collective solutions. The agreement with experiment is achieved through Model fits for few nuclei.
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quartic oscillator potential in the γ rigid regime of the collective Geometrical Model
European Physical Journal A, 2014Co-Authors: R BudacaAbstract:A prolate γ-rigid version of the Bohr-Mottelson Hamiltonian with a quartic anharmonic oscillator potential in β collective shape variable is used to describe the spectra for a variety of vibrational-like nuclei. Speculating the exact separation between the two Euler angles and the β variable, one arrives at a differential Schrodinger equation with a quartic anharmonic oscillator potential and a centrifugal-like barrier. The corresponding eigenvalue is approximated by an analytical formula depending only on a single parameter up to an overall scaling factor. The applicability of the Model is discussed in connection to the existence interval of the free parameter, which is limited by the accuracy of the approximation, and by comparison with the predictions of the related X(3) and X(3)-β 2 Models. The Model is applied to qualitatively describe the spectra for nine nuclei which exhibit near-vibrational features.
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Harmonic oscillator potential with a sextic anharmonicity in the prolate γ-rigid collective Geometrical Model
Elsevier, 2014Co-Authors: R BudacaAbstract:An analytical expression for the energy spectrum of the ground and β bands was obtained through the JWKB approximation in the axially symmetric γ-rigid regime of the Bohr–Mottelson Hamiltonian with an oscillator potential and a sextic anharmonicity in the β shape variable. Due to the scaling property of the problem, the resulting energy depends up to an overall multiplicative constant on a single parameter. Studying the behavior of the energy spectrum as a function of the free parameter, one establishes the present Model's place among other prolate γ-rigid Models and in the more general extent of collective solutions. The agreement with experiment is achieved through Model fits for few nuclei. Keywords: Collective states, Sextic oscillato
Moritz Mathieu - One of the best experts on this subject based on the ideXlab platform.
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probability of lightning strikes to air terminations of structures using the electro Geometrical Model theory and the statistics of lightning current parameters
Atmospheric Research, 2012Co-Authors: Alexander Kern, Christof Schelthoff, Moritz MathieuAbstract:Abstract In planning air-terminations for a structure to be protected the use of the rolling-sphere method (electro-Geometrical Model) is the best way from the physics of lightning point-of-view. Therefore, international standards prefer this method. However, using the rolling-sphere method only results in possible point-of-strikes on a structure without giving information about the probability of strikes at the individual points compared to others. Extending the electro-Geometrical Model using the probability distributions of natural lightning parameters, and implementing this idea into a numerical simulation computer code give the possibility to show the different exposure of individual points of a structure to direct lightning strikes and with that the different “efficiency” of air-terminations at these points. The results of the method described may help in the future, to optimize the planning of air-terminations due to their lightning strike capturing efficiency.
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probability of lightning strikes to air terminations of structures using the electro Geometrical Model theory and the statistics of lightning current parameters
International Conference on Lightning Protection, 2010Co-Authors: Alexander Kern, Christof Schelthoff, Moritz MathieuAbstract:Planning the air-terminations for a structure to be protected the use of the rolling-sphere method (electro-Geometrical Model) is the best way from the physics of lightning point-of-view. Therefore, international standards prefer this method. However, using the rolling-sphere method only results in possible point-of-strikes on a structure without giving information about the probability of strikes at the individual points compared to others.
Ever J. Barbero - One of the best experts on this subject based on the ideXlab platform.
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beyond plain weave fabrics i Geometrical Model
Composite Structures, 2011Co-Authors: Adi Adumitroaie, Ever J. BarberoAbstract:Abstract In response to the large variety of weaving styles offered by the textile industry, a new general approach for the Geometrical Modeling of 2D biaxial orthogonal woven fabric reinforcements for composite materials is proposed here. New Geometrical parameters are introduced in order to describe general families of twill and satin woven patterns, and a new classification of woven fabrics is proposed based on these parameters. Generation of the 3D internal geometry of the woven fabric families is achieved based on new Geometrical functions that consider the actual configuration of the composite material in all its complexity. The proposed Geometrical Model is intended as the foundation for further analytical or numerical Modeling of the mechanical properties of the composite materials reinforced with these fabrics.
Alexander Kern - One of the best experts on this subject based on the ideXlab platform.
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probability of lightning strikes to air terminations of structures using the electro Geometrical Model theory and the statistics of lightning current parameters
Atmospheric Research, 2012Co-Authors: Alexander Kern, Christof Schelthoff, Moritz MathieuAbstract:Abstract In planning air-terminations for a structure to be protected the use of the rolling-sphere method (electro-Geometrical Model) is the best way from the physics of lightning point-of-view. Therefore, international standards prefer this method. However, using the rolling-sphere method only results in possible point-of-strikes on a structure without giving information about the probability of strikes at the individual points compared to others. Extending the electro-Geometrical Model using the probability distributions of natural lightning parameters, and implementing this idea into a numerical simulation computer code give the possibility to show the different exposure of individual points of a structure to direct lightning strikes and with that the different “efficiency” of air-terminations at these points. The results of the method described may help in the future, to optimize the planning of air-terminations due to their lightning strike capturing efficiency.
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probability of lightning strikes to air terminations of structures using the electro Geometrical Model theory and the statistics of lightning current parameters
International Conference on Lightning Protection, 2010Co-Authors: Alexander Kern, Christof Schelthoff, Moritz MathieuAbstract:Planning the air-terminations for a structure to be protected the use of the rolling-sphere method (electro-Geometrical Model) is the best way from the physics of lightning point-of-view. Therefore, international standards prefer this method. However, using the rolling-sphere method only results in possible point-of-strikes on a structure without giving information about the probability of strikes at the individual points compared to others.
