Influence of rotation and initial stress on Propagation of Rayleigh waves in fiber-reinforced solidanisotropic magneto-thermo-viscoelastic media.

This paper is concerned with giving a mathematical model on the propagation of Rayleigh waves in a homogeneous magneto-thermo-viscoelastic,pre-stressed elastic half – space subjected to theinitial stress and rotation. The dispersion equation has been derived for a half-space, when both media are considered as pre-stressed and the effect of rotation and initial stressshown in earlier investigators.Numerical results have been obtained  in the physical domain. Numerical simulated results are depicted graphically to show the effect of rotation and magnetic field and initial stressonRayleigh wave velocity. Comparison was made with the results obtained in the presence and absence of the rotation , initial stressand magnetic field. The study shows that there is a variational effect of magneto-elasticityand rotation, initial stress on the Rayleigh wave velocity

Surface Waves In Homogeneous Visco-Elastic Media Of Higher Order Under The Influence Of Gravity And Surface Stresses

The aim of the present paper is to investigate the surface waves in a homogeneous, isotropic, visco-elastic solid medium of nth order, including time rate of strain under the influence of gravity and surface stresses. The theory of generalized surface waves is developed to investigate particular cases of waves such as the Stoneley, Rayleigh and Love waves. Corresponding equations have been obtained for different cases. These reduced to classical results, when the effects of gravity, surface stresses and viscosity are ignored. Keywords: Gravity, Surface waves, Visco-elasticity, Surface stresses

Effects of Rotation and Gravity Field on Surface Waves in Fibre-Reinforced Thermoelastic Media under Four Theories

Estimation is done to investigate the gravitational and rotational parameters effects on surface waves in fibre-reinforced thermoelastic media. The theory of generalized surface waves has been firstly developed and then it has been employed to investigate particular cases of waves, namely, Stoneley waves, Rayleigh waves, and Love waves. The analytical expressions for surface waves velocity and attenuation coefficient are obtained in the physical domain by using the harmonic vibrations and four thermoelastic theories. The wave velocity equations have been obtained in different cases. The numerical results are given for equation of coupled thermoelastic theory (C-T), Lord-Shulman theory (L-S), Green-Lindsay theory (G-L), and the linearized (G-N) theory of type II. Comparison was made with the results obtained in the presence and absence of gravity, rotation, and parameters for fibre-reinforced of the material media. The results obtained are displayed by graphs to clear the phenomena physical meaning. The results indicate that the effect of gravity, rotation, relaxation times, and parameters of fibre-reinforced of the material medium is very pronounced

Viscothermoelastic waves in a gravitated piezoelectric multilayered LEMV /CFRP cylinder coated with thin film

The present paper is concerned the effects of gravitational force and rotation in a composite multilayered hollowcylinder which contain inner and outer piezo-thermoelasticity layers bonded by Linear Elastic Material with Voids (LEMV) withinthe frame of dual-phase-lag model.Also the composite multilayered hollow cylinder coated with thin film is considered.Theequation of displacement components, temperature, and electric are obtained using linear theory of elasticity. The dispersionequations are acquired by means of traction free boundary conditions and are numerically analyzed for CdSe material.Theenumerated frequency, thermal and electrical nature against wave number in the presence of gravatity and rotation is presentedgraphically. Adhesive layer LEMV is compared with Carbon Fiber Reinforced Polymer (CFRP) in presence of gravity androtation

On Rayleigh wave field induced by surface stresses under the effect of gravity

The paper is concerned with development of the asymptotic formulation for surface wave field induced by vertical surface stress under the effect of gravity in the short-wave region. The approach relies on the methodology of hyperbolic-elliptic models for the Rayleigh wave and results in a regularly perturbed hyperbolic equation on the surface acting as a boundary condition for the elliptic equation governing decay over the interior. A special value of the Poisson's ratio v = 0.25 is pointed out, at which the effect of gravity disappears at leading order

Asymptotic Theory for Rayleigh and Rayleigh-Type Waves

Explicit asymptotic formulations are derived for Rayleigh and Rayleigh-type interfacial and edge waves. The hyperbolic–elliptic duality of surface and interfacial waves is established, along with the parabolic–elliptic duality of the dispersive edge wave on a Kirchhoff plate. The effects of anisotropy, piezoelectricity, thin elastic coatings, and mixed boundary conditions are taken into consideration. The advantages of the developed approach are illustrated by steady-state and transient problems for a moving load on an elastic half-space

Asymptotic models for surface waves in coated elastic solids

This thesis deals with surface wave propagation in elastic solids. It develops further the methodology of asymptotic hyperbolic-elliptic models for the surface elastic waves, aiming at two main areas, namely, accounting for the effects of a thin coating layer, as well as incorporating the influence of gravity. The derived model for surface waves on a coated elastic half space subject to prescribed surface stresses reflects the physical nature of elastic surface waves, for which the decay over the interior is described by a "pseudo-static" elliptic equation, whereas wave propagation along the boundary is governed by a singularly perturbed hyperbolic equation, with the perturbation in the form of a pseudo-differential operator. This perturbative term originates from the effect of a thin coating layer, which is modelled in terms of effective boundary conditions, derived within the long wave limit approximation of the corresponding problem in linear elasticity. Various types of coatings are studied in this thesis, including anisotropic and vertically inhomogeneous thin layers. The analysis reveals a qualitatively similar hyperbolic equation, singularly perturbed by a pseudo differential operator, with the appropriate coeffcient incorporating the overall effect of the material properties of the coating and the substrate. The established methodology is then illustrated for approximate treatment of several rather technical problems in elastodynamics, in particular, analysis of moving loads on a coated half-plane. The implementation of the hyperbolic-elliptic model allows a natural classification of scenarios and elegant approximations of the exact solution, with clear physical interpretation of the associated numerical illustrations of nearsurface dynamics for several types of vertical inhomogeneity. Finally, the effect of gravity is embedded into the developed methodology of hyperbolicelliptic asymptotic models for surface waves. As a result, the wave equation on the surface is regularly perturbed by a pseudo differential operator, accounting for the effect of the gravitational field

Dynamic Response of Heterogeneity and Reinforcement on the Propagation of Torsional Surface Waves

This paper aims to investigate the effect of reinforcement and heterogeneity on the propagation of torsional surface waves. Geometry of the problem is consists of heterogeneous fibre-reinforced layer lying over a heterogeneous isotropic half-space. Heterogeneity in the layer is caused due to exponential variation of elastic parameters whereas quadratic variation in elastic parameters is considered for half-space. Dispersion relation for torsional surface waves has been obtained and matched with classical Love wave equation by taking an isotropic homogeneous layer lying over an isotropic homogeneous half-space. Some existing results have been deduced as particular case of the present study. Velocity profile of surface waves is compared for both, reinforced and reinforced free cases. Numerical examples have been discussed by taking steel fibre-reinforced material. Graphical representation has been made to exhibit the findings