The Experts below are selected from a list of 294 Experts worldwide ranked by ideXlab platform
Baljeet Singh - One of the best experts on this subject based on the ideXlab platform.
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the effect of rotation and initial stress on the propagation of waves in a transversely isotropic Elastic Solid
Wave Motion, 2014Co-Authors: R W Ogden, Baljeet SinghAbstract:In this paper the equations governing small amplitude motions in a rotating transversely isotropic initially stressed Elastic Solid are derived, both for compressible and incompressible linearly Elastic materials. The equations are first applied to study the effects of initial stress and rotation on the speed of homogeneous plane waves propagating in a configuration with uniform initial stress. The general forms of the constitutive law, stresses and the Elasticity tensor are derived within the finite deformation context and then summarized for the considered transversely isotropic material with initial stress in terms of invariants, following which they are specialized for linear Elastic response and, for an incompressible material, to the case of plane strain, which involves considerable simplification. The equations for two-dimensional motions in the considered plane are then applied to the study of Rayleigh waves in a rotating half-space with the initial stress parallel to its boundary and the preferred direction of transverse isotropy either parallel to or normal to the boundary within the sagittal plane. The secular equation governing the wave speed is then derived for a general strain–energy function in the plane strain specialization, which involves only two material parameters. The results are illustrated graphically, first by showing how the wave speed depends on the material parameters and the rotation without specifying the constitutive law and, second, for a simple material model to highlight the effects of the rotation and initial stress on the surface wave speed.
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reflection of sv waves from the free surface of an Elastic Solid in generalized thermoElastic diffusion
Journal of Sound and Vibration, 2006Co-Authors: Baljeet SinghAbstract:The governing equations for two-dimensional generalized thermoElastic diffusion in an Elastic Solid are solved. There exist three compressional waves and a shear vertical (SV) wave. The reflection phenomena of SV wave from the free surface of an Elastic Solid with generalized thermoElastic diffusion is considered. The closed-form expressions for the reflection coefficients for various reflected waves are obtained. These reflection coefficients are found to depend upon the angle of incidence of SV wave, thermoElastic diffusion parameter and other material constants. The numerical values of modulus of the reflection coefficients are presented graphically for different thermal and diffusion parameters.
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reflection of p and sv waves from free surface of an Elastic Solid with generalized thermodiffusion
Journal of Earth System Science, 2005Co-Authors: Baljeet SinghAbstract:The governing equations for generalized thermodiffusion in an Elastic Solid are solved. There exists three kinds of dilatational waves and a Shear Vertical (SV) wave in a two-dimensional model of the Solid. The reflection phenomena of P and SV waves from free surface of an Elastic Solid with thermodiffusion is considered. The boundary conditions are solved to obtain a system of four non-homogeneous equations for reflection coefficients. These reflection coefficients are found to depend upon the angle of incidence of P and SV waves, thermodiffusion parameters and other material constants. The numerical values of modulus of the reflection coefficients are presented graphically for different values of thermodiffusion parameters. The dimensional velocities of various plane waves are also computed for different material constants.
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Reflection of plane waves from free surface of a microstretch Elastic Solid
Journal of Earth System Science, 2002Co-Authors: Baljeet SinghAbstract:In the present investigation, it is shown that there exists five basic waves in a microstretch Elastic Solid half-space. The problem of reflection of plane waves from free surface of a microstretch Elastic Solid half-space is studied. The energy ratios for various reflected waves are obtained for aluminiumepoxy composite as a microstretch Elastic Solid half-space. The variations of the energy ratios with the angle of incidence are shown graphically. The microstretch effect is shown on various reflected waves.
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Reflection and refraction of micropolar Elastic waves at a loosely bonded interface between viscoElastic Solid and micropolar Elastic Solid
International Journal of Engineering Science, 1998Co-Authors: Baljeet Singh, Rajneesh KumarAbstract:The problem of a reflection and refraction of micropolar Elastic waves at a loosely bonded interface between a viscoElastic Solid and a micropolar Elastic Solid is studied. The amplitude ratios for the different reflected and refracted waves have been obtained. Numerical values of the amplitude ratios have been computed for different values of bonding parameter and are plotted against the angle of emergence. The numerical calculations reveal that the amplitude ratios of reflected and refracted waves depend on the angle of emergence as well as on the bonding parameter.
Animangsu Ghatak - One of the best experts on this subject based on the ideXlab platform.
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surface tension induced flattening of a nearly plane Elastic Solid
Physical Review E, 2012Co-Authors: Anand Jagota, Dadhichi Paretkar, Animangsu GhatakAbstract:: We report direct measurement of surface deformation in soft Solids due to their surface tension. Gel replicas of poly(dimethysiloxane) masters with rippled surfaces are found to have amplitudes that decrease with decreasing gel modulus. Surface undulations of a thin elastomeric film are attenuated when it is oxidized by brief exposure to oxygen plasma. Surface deformation in both cases is modeled successfully as driven by surface tension and resisted by Elasticity. Our results show that surface tension of soft Solids drives significant deformation, and that the latter can be used to determine the former.
Francois Valdivieso - One of the best experts on this subject based on the ideXlab platform.
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a finite element based level set method for fluid Elastic Solid interaction with surface tension
International Journal for Numerical Methods in Engineering, 2013Co-Authors: Pino D Munoz, Julien Bruchon, Sylvain Drapier, Francois ValdiviesoAbstract:SUMMARY A numerical method for simulating fluid–Elastic Solid interaction with surface tension is presented. A level set method is used to capture the interface between the Solid bodies and the incompressible surrounding fluid, within an Eulerian approach. The mixed velocity–pressure variational formulation is established for the global coupled mechanical problem and discretized using a continuous linear approximation in both velocity and pressure. Three ways are investigated to reduce the spurious oscillations of the pressure that appear at the fluid–Solid interface. First, two stabilized finite element methods are used: the MINI-element and the algebraic subgrid method. Second, the surface integral corresponding to the surface tension term is treated either by the continuum surface force technique or by a surface local reconstruction algorithm. Finally, besides the direct evaluation method proposed by Bruchon et al., an alternative method is proposed to avoid the explicit computation of the surface curvature, which may be a source of difficulty. These different issues are addressed through various numerical examples, such as the two incompressible fluid flow, the Elastic inclusion embedded into a Newtonian fluid, or the study of a granular packing. Copyright © 2012 John Wiley & Sons, Ltd.
Anand Jagota - One of the best experts on this subject based on the ideXlab platform.
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surface tension induced flattening of a nearly plane Elastic Solid
Physical Review E, 2012Co-Authors: Anand Jagota, Dadhichi Paretkar, Animangsu GhatakAbstract:: We report direct measurement of surface deformation in soft Solids due to their surface tension. Gel replicas of poly(dimethysiloxane) masters with rippled surfaces are found to have amplitudes that decrease with decreasing gel modulus. Surface undulations of a thin elastomeric film are attenuated when it is oxidized by brief exposure to oxygen plasma. Surface deformation in both cases is modeled successfully as driven by surface tension and resisted by Elasticity. Our results show that surface tension of soft Solids drives significant deformation, and that the latter can be used to determine the former.
Sergey A Kostyrko - One of the best experts on this subject based on the ideXlab platform.
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surface effects in an Elastic Solid with nanosized surface asperities
International Journal of Solids and Structures, 2016Co-Authors: M A Grekov, Sergey A KostyrkoAbstract:Abstract The effects of surface Elasticity and surface tension on the stress field near nanosized surface asperities having at least one dimension in the range 1–100 nm is investigated. The general two-dimensional problem for an isotropic stressed Solid with an arbitrary roughened surface at the nanoscale is considered. The bulk material is idealized as an Elastic semi-infinite continuum. In accordance with the Gurtin–Murdoch model, the surface is represented as a coherently bonded Elastic membrane. The surface properties are characterized by the residual surface stress (surface tension) and the surface Lame constants, which differ from those of the bulk. The boundary conditions at the curved surface are described by the generalized Young–Laplace equation. Using a specific approach to the boundary perturbation technique, Goursat–Kolosov complex potentials, and Muskhelishvili representations, the boundary value problem is reduced to the solution of a hypersingular integral equation. Based on the first-order approximation, some numerical results in the case of a periodic shape of the surface and the analysis of the influence of surface stress, surface tension, the surface shape, and the size of the asperity on the hoop stress at the surface are presented. It is found that the surface tension alone produces a high level of stress concentration, much more than can be reduced by surface stress arising as a result of deformation. The stress formula obtained by Gao (1991) for sinusoidal surfaces at the macrolevel is extended to nanosized surface asperities.
