The Experts below are selected from a list of 10233 Experts worldwide ranked by ideXlab platform
Manuel Pastor - One of the best experts on this subject based on the ideXlab platform.
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Wave propagation and localization problems in saturated viscoplastic geomaterials
International Journal for Numerical Methods in Engineering, 2006Co-Authors: M. Mabssout, M.i. Herreros, Manuel PastorAbstract:This paper presents an improved algorithm to deal with wave propagation and localization problems in saturated viscoplastic geomaterials. It consists of a mixed formulation in terms of effective stress, velocity and pore pressure that uses a fractional step algorithm allowing the use of equal order of interpolation for the three variables and the simplest element such as the Linear Triangle. The viscoplastic model used is of modified cam-clay type. Viscoplasticity results in a strong source term that deteriorates the accuracy of the two-step Taylor–Galerkin algorithm. Therefore a Runge–Kutta splitting scheme has been used to deal with the source terms, resulting in a better accuracy of the method. Copyright © 2006 John Wiley & Sons, Ltd.
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A Runge-Kutta, Taylor-Galerkin scheme for hyperbolic systems with source terms. Application to shock wave propagation in viscoplastic geomaterials
International Journal for Numerical and Analytical Methods in Geomechanics, 2006Co-Authors: M. Mabssout, Manuel Pastor, M.i. Herreros, M. QuecedoAbstract:This paper presents an alternative formulation of Solid Dynamics problems based on (i) a mathematical model consisting of a system of hyperbolic PDEs where the source term is originated by the viscoplastic strain rate and (ii) a splitting scheme where the two-step Taylor–Galerkin is used for the advective part of the PDE operator while the sources are integrated using a fourth-order Runge–Kutta. Use of the splitting scheme results in a higher accuracy than that of the original two-step Taylor–Galerkin. The scheme performs well when used with Linear Triangle or tetrahedra for (i) bending-dominated situations (ii) localized failure under dynamic conditions and keeps the advantages of the two-step Taylor–Galerkin concerning numerical dispersion and damping of short wavelengths. Copyright © 2006 John Wiley & Sons, Ltd.
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enhanced Linear Triangle for plasticity problems in j 2 solids
Computer Methods in Applied Mechanics and Engineering, 2000Co-Authors: M. Quecedo, Manuel Pastor, O. C. ZienkiewiczAbstract:Due to their economy and capability to reproduce high gradient zones, low order elements are of great interest in the calculations involving localized failure. However, the performance of the simplest element, the three nodes Triangle, under incompressible and bending dominated situations is very poor and the computed results unreliable. This paper presents an inexpensive three fields, u–p–σ, formulation solving these issues as shown in the examples of application.
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Enhanced Linear Triangle for plasticity problems in J′2 solids
Computer Methods in Applied Mechanics and Engineering, 2000Co-Authors: M. Quecedo, Manuel Pastor, O. C. ZienkiewiczAbstract:Due to their economy and capability to reproduce high gradient zones, low order elements are of great interest in the calculations involving localized failure. However, the performance of the simplest element, the three nodes Triangle, under incompressible and bending dominated situations is very poor and the computed results unreliable. This paper presents an inexpensive three fields, u–p–σ, formulation solving these issues as shown in the examples of application.
M. Quecedo - One of the best experts on this subject based on the ideXlab platform.
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A Runge-Kutta, Taylor-Galerkin scheme for hyperbolic systems with source terms. Application to shock wave propagation in viscoplastic geomaterials
International Journal for Numerical and Analytical Methods in Geomechanics, 2006Co-Authors: M. Mabssout, Manuel Pastor, M.i. Herreros, M. QuecedoAbstract:This paper presents an alternative formulation of Solid Dynamics problems based on (i) a mathematical model consisting of a system of hyperbolic PDEs where the source term is originated by the viscoplastic strain rate and (ii) a splitting scheme where the two-step Taylor–Galerkin is used for the advective part of the PDE operator while the sources are integrated using a fourth-order Runge–Kutta. Use of the splitting scheme results in a higher accuracy than that of the original two-step Taylor–Galerkin. The scheme performs well when used with Linear Triangle or tetrahedra for (i) bending-dominated situations (ii) localized failure under dynamic conditions and keeps the advantages of the two-step Taylor–Galerkin concerning numerical dispersion and damping of short wavelengths. Copyright © 2006 John Wiley & Sons, Ltd.
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enhanced Linear Triangle for plasticity problems in j 2 solids
Computer Methods in Applied Mechanics and Engineering, 2000Co-Authors: M. Quecedo, Manuel Pastor, O. C. ZienkiewiczAbstract:Due to their economy and capability to reproduce high gradient zones, low order elements are of great interest in the calculations involving localized failure. However, the performance of the simplest element, the three nodes Triangle, under incompressible and bending dominated situations is very poor and the computed results unreliable. This paper presents an inexpensive three fields, u–p–σ, formulation solving these issues as shown in the examples of application.
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Enhanced Linear Triangle for plasticity problems in J′2 solids
Computer Methods in Applied Mechanics and Engineering, 2000Co-Authors: M. Quecedo, Manuel Pastor, O. C. ZienkiewiczAbstract:Due to their economy and capability to reproduce high gradient zones, low order elements are of great interest in the calculations involving localized failure. However, the performance of the simplest element, the three nodes Triangle, under incompressible and bending dominated situations is very poor and the computed results unreliable. This paper presents an inexpensive three fields, u–p–σ, formulation solving these issues as shown in the examples of application.
O. C. Zienkiewicz - One of the best experts on this subject based on the ideXlab platform.
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enhanced Linear Triangle for plasticity problems in j 2 solids
Computer Methods in Applied Mechanics and Engineering, 2000Co-Authors: M. Quecedo, Manuel Pastor, O. C. ZienkiewiczAbstract:Due to their economy and capability to reproduce high gradient zones, low order elements are of great interest in the calculations involving localized failure. However, the performance of the simplest element, the three nodes Triangle, under incompressible and bending dominated situations is very poor and the computed results unreliable. This paper presents an inexpensive three fields, u–p–σ, formulation solving these issues as shown in the examples of application.
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Enhanced Linear Triangle for plasticity problems in J′2 solids
Computer Methods in Applied Mechanics and Engineering, 2000Co-Authors: M. Quecedo, Manuel Pastor, O. C. ZienkiewiczAbstract:Due to their economy and capability to reproduce high gradient zones, low order elements are of great interest in the calculations involving localized failure. However, the performance of the simplest element, the three nodes Triangle, under incompressible and bending dominated situations is very poor and the computed results unreliable. This paper presents an inexpensive three fields, u–p–σ, formulation solving these issues as shown in the examples of application.
Baining Guo - One of the best experts on this subject based on the ideXlab platform.
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Rendering Techniques - Real-time multi-perspective rendering on graphics hardware
2006Co-Authors: Xianyou Hou, Li-yi Wei, Heung-yeung Shum, Baining GuoAbstract:Multi-perspective rendering has a variety of applications; examples include lens refraction, curved mirror re- flection, caustics, as well depiction and visualization. However, multi-perspective rendering is not yet practical on polygonal graphics hardware, which so far has utilized mostly single-perspective (pin-hole or orthographic) projections. In this paper, we present a methodology for real-time multi-perspective rendering on polygonal graphics hardware. Our approach approximates a general multi-perspective projection surface (such as a curved mirror and lens) via a piecewise-Linear Triangle mesh, upon which each Triangle is a simple multi-perspective camera, parameterized by three rays at Triangle vertices. We derive analytic formula showing that each Triangle projection can be implemented as a pair of vertex and fragment programs on programmable graphics hardware. We demonstrate real-time performance of a variety of applications enabled by our technique, including reflection, refraction, caustics, and visualization.
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SIGGRAPH Sketches - Real-time multi-perspective rendering on graphics hardware
ACM SIGGRAPH 2006 Sketches on - SIGGRAPH '06, 2006Co-Authors: Xianyou Hou, Li-yi Wei, Heung-yeung Shum, Baining GuoAbstract:Multi-perspective rendering has a variety of applications; examples include lens refraction, curved mirror reflection, caustics, as well depiction and visualization. However, multi-perspective rendering is not yet practical on polygonal graphics hardware, which so far has utilized mostly single-perspective (pin-hole or orthographic) projections.In this paper, we present a methodology for real-time multi-perspective rendering on polygonal graphics hardware. Our approach approximates a general multi-perspective projection surface (such as a curved mirror and lens) via a piecewise-Linear Triangle mesh, upon which each Triangle is a simple multi-perspective camera, parameterized by three rays at Triangle vertices. We derive analytic formula showing that each Triangle projection can be implemented as a pair of vertex and fragment programs on programmable graphics hardware. We demonstrate real-time performance of a variety of applications enabled by our technique, including reflection, refraction, caustics, and visualization.
M. Mabssout - One of the best experts on this subject based on the ideXlab platform.
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Wave propagation and localization problems in saturated viscoplastic geomaterials
International Journal for Numerical Methods in Engineering, 2006Co-Authors: M. Mabssout, M.i. Herreros, Manuel PastorAbstract:This paper presents an improved algorithm to deal with wave propagation and localization problems in saturated viscoplastic geomaterials. It consists of a mixed formulation in terms of effective stress, velocity and pore pressure that uses a fractional step algorithm allowing the use of equal order of interpolation for the three variables and the simplest element such as the Linear Triangle. The viscoplastic model used is of modified cam-clay type. Viscoplasticity results in a strong source term that deteriorates the accuracy of the two-step Taylor–Galerkin algorithm. Therefore a Runge–Kutta splitting scheme has been used to deal with the source terms, resulting in a better accuracy of the method. Copyright © 2006 John Wiley & Sons, Ltd.
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A Runge-Kutta, Taylor-Galerkin scheme for hyperbolic systems with source terms. Application to shock wave propagation in viscoplastic geomaterials
International Journal for Numerical and Analytical Methods in Geomechanics, 2006Co-Authors: M. Mabssout, Manuel Pastor, M.i. Herreros, M. QuecedoAbstract:This paper presents an alternative formulation of Solid Dynamics problems based on (i) a mathematical model consisting of a system of hyperbolic PDEs where the source term is originated by the viscoplastic strain rate and (ii) a splitting scheme where the two-step Taylor–Galerkin is used for the advective part of the PDE operator while the sources are integrated using a fourth-order Runge–Kutta. Use of the splitting scheme results in a higher accuracy than that of the original two-step Taylor–Galerkin. The scheme performs well when used with Linear Triangle or tetrahedra for (i) bending-dominated situations (ii) localized failure under dynamic conditions and keeps the advantages of the two-step Taylor–Galerkin concerning numerical dispersion and damping of short wavelengths. Copyright © 2006 John Wiley & Sons, Ltd.