The Experts below are selected from a list of 42075 Experts worldwide ranked by ideXlab platform
Chi Fai Cheung - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Material Anisotropy on shear angle prediction in metal cutting—a mesoplasticity approach
International Journal of Mechanical Sciences, 2003Co-Authors: Bun Lee, Y.k. Sze, Chi Fai CheungAbstract:Material Anisotropy plays an important role in the formation of shear angle in metal cutting. Crystallographic textures contribute to an important source of Material Anisotropy. A simplified mesoplasticity model is proposed in this paper to predict the effect of crystallographic orientations on the shear angle formation in machining a polycrystalline work Material. The most likely shear angle is the one at which the Taylor factor is minimum. A good agreement is found between the predicted shear angle in machining a polycrystalline OFHC copper and the experimental data reported in the published literature. The assumptions made in the model approximate well the cutting conditions commonly encountered in single point diamond turning process.
-
effect of Material Anisotropy on shear angle prediction in metal cutting a mesoplasticity approach
International Journal of Mechanical Sciences, 2003Co-Authors: W B Lee, Y.k. Sze, Chi Fai CheungAbstract:Material Anisotropy plays an important role in the formation of shear angle in metal cutting. Crystallographic textures contribute to an important source of Material Anisotropy. A simplified mesoplasticity model is proposed in this paper to predict the effect of crystallographic orientations on the shear angle formation in machining a polycrystalline work Material. The most likely shear angle is the one at which the Taylor factor is minimum. A good agreement is found between the predicted shear angle in machining a polycrystalline OFHC copper and the experimental data reported in the published literature. The assumptions made in the model approximate well the cutting conditions commonly encountered in single point diamond turning process.
Vincent Laude - One of the best experts on this subject based on the ideXlab platform.
-
Material Anisotropy unveiled by random scattering of surface acoustic waves
Applied Physics Letters, 2011Co-Authors: Vincent Laude, Sarah Benchabane, Kimmo Kokkonen, Matti KaivolaAbstract:We consider launching a monochromatic surface acoustic wave packet on a large set of random scatterers. The interference of the multiple scattered waves creates a random pattern of ripples on the crystal surface that is recorded by optical interferometry. The Fourier transform of the amplitude and phase data of the measured wave field unveils the complete slowness curve, i.e., the wave-vector as a function of the propagation angle. A simple acoustic speckle model is proposed to explain this observation.
-
Polarization state and level repulsion in two-dimensional phononic crystals and waveguides in the presence of Material Anisotropy
Journal of Physics D: Applied Physics, 2010Co-Authors: Younes Achaoui, Abdelkrim Khelif, Sarah Benchabane, Vincent LaudeAbstract:We investigate the polarization of Bloch waves in two dimensional piezoelectric phononic crystals and phononic crystal waveguides managed therein. It is found that in addition to the strong coupling induced for waves polarized in the plane of the periodic structuration, a weaker but non negligible coupling of polarization components originates from Material Anisotropy. Numerical illustrations are given for an array of air holes in lithium niobate arranged according to a square lattice. It is observed that when a band mostly polarized in-plane gets close to a band mostly polarized out-of-plane, a phenomenon of repelling can occur, that in some instances introduces a local band gap. This interaction is accompanied by a transfer of the polarization state from one band to the other. Polarization state and level repulsion in two-dimensional phononic crystals and waveguides in the presenc 1. introduction Phononic crystals are periodic structures that can give rise to complete band gaps (BG) for acoustic waves in fluids or elastic waves (acoustic phonons) in solids [ 1, 2 ], in the very same way that photonic crystals prohibit the propagation of optical or electromagnetic waves [ 3, 4 ]. The dispersion of the bands composing the band structure, the frequency position and the width of the band gaps are conditioned by the contrast between Material constants of the constituent media on the one hand, and by the filling fraction, the geometrical shape of the inclusions and the lattice topology on the other hand. Within a frequency band gap, a phononic crystal acts as a mirror for incident waves, as a result of destructive interferences between waves scattered on the periodic inclusions. Thanks to the wide operating frequency range of acoustic and elastic waves, complete band gaps have been demonstrated theoretically and experimentally at different scales, for bulk waves [ 2, 5, 6 ] and surface waves [ 7, 8, 9, 10, 11 ], as well as for phononic crystal slabs [ 12, 13, 14 ]. Phononic crystals also allow for the obtaining of confined states or guided waves through the introduction of point or linear defects [ 15, 16, 17, 18 ]. Phononic waveguides, resonators and stubs have been proposed as possible ways to create filtering and multiplexing structures based on the coupling of resonance and waveguiding phenomena [ 19, 20, 21 ]. In the case of acoustic waves in fluids, because of the single polarization involved (longitudinal), the band structure in the perfect crystal case and the transmission coefficient in the waveguide case are usually considered sufficient to characterize a phononic crystal. But for elastic waves propagating in a solid, both transverse and longitudinal polarizations exist and are possibly coupled owing to the periodic structuration. Taking the polarization state into account in the analysis of band diagrams is hence compulsory to show a complete picture of elastic wave propagation. This has for example been shown by a previous study dedicated to polarization effects in a perfect 2D phononic crystal made of air inclusions in an epoxy matrix [ 22 ]. This work highlighted the influence of the filling fraction on the coupling between in-plane transverse and longitudinal polarizations, where in-plane refers to the plane normal to the inclusion axis. The in-plane polarization components were found to be more coupled for higher filling fractions and a continuous variation of the polarization when the wavevector sweeps the first Brillouin zone was reported. This continuity of the elastic displacement fields along band structures has also been investigated in order to study the repulsion level between different branches in the band diagram for both one[ 23 ] or two- [ 24 ] dimensional phononic crystals. We are not aware of similar works for phononic crystals involving anisotropic Materials or phononic waveguides, though the dependence of the guided waves dispersion on a change in the central inclusion radius or in the waveguide width has been reported recently [ 25, 26 ]. With the configurations proposed in these works, some branches initially located outside the band gap in the case of the perfect phononic crystal can enter or exit the band gap when the dimensions of the defect vary. The displacement field of some confined modes was reported as well
-
Polarization state and level repulsion in two-dimensional phononic crystals and waveguides in the presence of Material Anisotropy
Journal of Physics D: Applied Physics, 2010Co-Authors: Younes Achaoui, Abdelkrim Khelif, Sarah Benchabane, Vincent LaudeAbstract:We investigate the polarization of Bloch waves in two-dimensional piezoelectric phononic crystals and phononic crystal waveguides managed therein. It is found that in addition to the strong coupling induced for waves polarized in the plane of the periodic structuration, a weaker but non-negligible coupling of polarization components originates from Material Anisotropy. Numerical illustrations are given for an array of air holes in lithium niobate arranged according to a square lattice. It is observed that when a band mostly polarized in-plane gets close to a band mostly polarized out-of-plane, a phenomenon of repelling can occur, that in some instances introduces a local band gap. This interaction is accompanied by a transfer of the polarization state from one band to the other.
Y.k. Sze - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Material Anisotropy on shear angle prediction in metal cutting—a mesoplasticity approach
International Journal of Mechanical Sciences, 2003Co-Authors: Bun Lee, Y.k. Sze, Chi Fai CheungAbstract:Material Anisotropy plays an important role in the formation of shear angle in metal cutting. Crystallographic textures contribute to an important source of Material Anisotropy. A simplified mesoplasticity model is proposed in this paper to predict the effect of crystallographic orientations on the shear angle formation in machining a polycrystalline work Material. The most likely shear angle is the one at which the Taylor factor is minimum. A good agreement is found between the predicted shear angle in machining a polycrystalline OFHC copper and the experimental data reported in the published literature. The assumptions made in the model approximate well the cutting conditions commonly encountered in single point diamond turning process.
-
effect of Material Anisotropy on shear angle prediction in metal cutting a mesoplasticity approach
International Journal of Mechanical Sciences, 2003Co-Authors: W B Lee, Y.k. Sze, Chi Fai CheungAbstract:Material Anisotropy plays an important role in the formation of shear angle in metal cutting. Crystallographic textures contribute to an important source of Material Anisotropy. A simplified mesoplasticity model is proposed in this paper to predict the effect of crystallographic orientations on the shear angle formation in machining a polycrystalline work Material. The most likely shear angle is the one at which the Taylor factor is minimum. A good agreement is found between the predicted shear angle in machining a polycrystalline OFHC copper and the experimental data reported in the published literature. The assumptions made in the model approximate well the cutting conditions commonly encountered in single point diamond turning process.
Bun Lee - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Material Anisotropy on shear angle prediction in metal cutting—a mesoplasticity approach
International Journal of Mechanical Sciences, 2003Co-Authors: Bun Lee, Y.k. Sze, Chi Fai CheungAbstract:Material Anisotropy plays an important role in the formation of shear angle in metal cutting. Crystallographic textures contribute to an important source of Material Anisotropy. A simplified mesoplasticity model is proposed in this paper to predict the effect of crystallographic orientations on the shear angle formation in machining a polycrystalline work Material. The most likely shear angle is the one at which the Taylor factor is minimum. A good agreement is found between the predicted shear angle in machining a polycrystalline OFHC copper and the experimental data reported in the published literature. The assumptions made in the model approximate well the cutting conditions commonly encountered in single point diamond turning process.
W B Lee - One of the best experts on this subject based on the ideXlab platform.
-
effect of Material Anisotropy on shear angle prediction in metal cutting a mesoplasticity approach
International Journal of Mechanical Sciences, 2003Co-Authors: W B Lee, Y.k. Sze, Chi Fai CheungAbstract:Material Anisotropy plays an important role in the formation of shear angle in metal cutting. Crystallographic textures contribute to an important source of Material Anisotropy. A simplified mesoplasticity model is proposed in this paper to predict the effect of crystallographic orientations on the shear angle formation in machining a polycrystalline work Material. The most likely shear angle is the one at which the Taylor factor is minimum. A good agreement is found between the predicted shear angle in machining a polycrystalline OFHC copper and the experimental data reported in the published literature. The assumptions made in the model approximate well the cutting conditions commonly encountered in single point diamond turning process.