The Experts below are selected from a list of 51939 Experts worldwide ranked by ideXlab platform
Y M Gupta - One of the best experts on this subject based on the ideXlab platform.
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Anisotropic Material model and wave propagation simulations for shocked pentaerythritol tetranitrate single crystals
Journal of Applied Physics, 2010Co-Authors: J M Winey, Y M GuptaAbstract:An Anisotropic continuum Material model was developed to describe the thermomechanical response of unreacted pentaerythritol tetranitrate (PETN) single crystals to shock wave loading. Using this model, which incorporates nonlinear elasticity and crystal plasticity in a thermodynamically consistent tensor formulation, wave propagation simulations were performed to compare to experimental wave profiles [J. J. Dick and J. P. Ritchie, J. Appl. Phys. 76, 2726 (1994)] for PETN crystals under plate impact loading to 1.2 GPa. Our simulations show that for shock propagation along the [100] orientation where deformation across shear planes is sterically unhindered, a dislocation-based model provides a good match to the wave profile data. For shock propagation along the [110] direction, where deformation across shear planes is sterically hindered, a dislocation-based model cannot account for the observed strain-softening behavior. Instead, a shear cracking model was developed, providing good agreement with the data ...
Boon S Ooi - One of the best experts on this subject based on the ideXlab platform.
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a simple fdtd algorithm for simulating em wave propagation in general dispersive Anisotropic Material
IEEE Transactions on Antennas and Propagation, 2013Co-Authors: Ahmad Aljabr, M A Alsunaidi, Boon S OoiAbstract:In this paper, an finite-difference time-domain (FDTD) algorithm for simulating propagation of EM waves in Anisotropic Material is presented. The algorithm is based on the auxiliary differential equation and the general polarization formulation. In Anisotropic Materials, electric fields are coupled and elements in the permittivity tensor are, in general, multiterm dispersive. The presented algorithm resolves the field coupling using a formulation based on electric polarizations. It also offers a simple procedure for the treatment of multiterm dispersion in the FDTD scheme. The algorithm is tested by simulating wave propagation in 1-D magnetized plasma showing excellent agreement with analytical solutions. Extension of the algorithm to multidimensional structures is straightforward. The presented algorithm is efficient and simple compared to other algorithms found in the literature.
J M Winey - One of the best experts on this subject based on the ideXlab platform.
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Anisotropic Material model and wave propagation simulations for shocked pentaerythritol tetranitrate single crystals
Journal of Applied Physics, 2010Co-Authors: J M Winey, Y M GuptaAbstract:An Anisotropic continuum Material model was developed to describe the thermomechanical response of unreacted pentaerythritol tetranitrate (PETN) single crystals to shock wave loading. Using this model, which incorporates nonlinear elasticity and crystal plasticity in a thermodynamically consistent tensor formulation, wave propagation simulations were performed to compare to experimental wave profiles [J. J. Dick and J. P. Ritchie, J. Appl. Phys. 76, 2726 (1994)] for PETN crystals under plate impact loading to 1.2 GPa. Our simulations show that for shock propagation along the [100] orientation where deformation across shear planes is sterically unhindered, a dislocation-based model provides a good match to the wave profile data. For shock propagation along the [110] direction, where deformation across shear planes is sterically hindered, a dislocation-based model cannot account for the observed strain-softening behavior. Instead, a shear cracking model was developed, providing good agreement with the data ...
Salah Naili - One of the best experts on this subject based on the ideXlab platform.
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Simulation of transient ultrasonic wave propagation in fluid-loaded heterogeneous cortical bone
Vietnam Journal of Mechanics, 2012Co-Authors: Vuhieu Nguyen, Salah NailiAbstract:This work deals with the ultrasonic wave propagation in the cortical layer of long bones which is known as being a functionally-graded Anisotropic Material coupled with fluids. The motivation arises from mechanical modeling of the ultrasound axial transmission technique in vivo for cortical long bone which is known as being a functionally-graded Anisotropic Material. The proposed method is based on a combined Laplace-Fourier transform which substitutes a problem defined by partial differential equations into a system of differential equations established in the frequency-wavenumber domain. In the spectral domain, as radiation conditions may be exactly introduced in the infinite fluid halfspaces, only the heterogeneous solid layer needs to be analyzed using finite element method. Several numerical tests are presented showing very good performance of the proposed approach. Keywords: Spectral finite element, transient wave, ultrasound, Anisotropic, vibroacoustic, cortical bone, axial transmission.
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Simulation of transient ultrasonic wave propagation in fluid-loaded heterogeneous cortical bone
Vietnam Journal of Mechanics, 2011Co-Authors: Vuhieu Nguyen, Salah NailiAbstract:This work deals with the ultrasonic wave propagation in the cortical layer of long bones which is known as being a functionally-graded Anisotropic Material coupled with fluids. The motivation arises from mechanical modeling of the ultrasound axial transmission technique in vivo for cortical long bone which is known as being a functionally-graded Anisotropic Material. The proposed method is based on a combined Laplace-Fourier transform which substitutes a problem defined by partial differential equations into a system of differential equations established in the frequency-wavenumber domain. In the spectral domain, as radiation conditions may be exactly introduced in the infinite fluid half-spaces, only the heterogeneous solid layer needs to be analyzed using finite element method. Several numerical tests are presented showing very good performance of the proposed approach.
Ahmad Aljabr - One of the best experts on this subject based on the ideXlab platform.
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a simple fdtd algorithm for simulating em wave propagation in general dispersive Anisotropic Material
IEEE Transactions on Antennas and Propagation, 2013Co-Authors: Ahmad Aljabr, M A Alsunaidi, Boon S OoiAbstract:In this paper, an finite-difference time-domain (FDTD) algorithm for simulating propagation of EM waves in Anisotropic Material is presented. The algorithm is based on the auxiliary differential equation and the general polarization formulation. In Anisotropic Materials, electric fields are coupled and elements in the permittivity tensor are, in general, multiterm dispersive. The presented algorithm resolves the field coupling using a formulation based on electric polarizations. It also offers a simple procedure for the treatment of multiterm dispersion in the FDTD scheme. The algorithm is tested by simulating wave propagation in 1-D magnetized plasma showing excellent agreement with analytical solutions. Extension of the algorithm to multidimensional structures is straightforward. The presented algorithm is efficient and simple compared to other algorithms found in the literature.
