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Propagation and reflection of plane waves in a rotating magneto-elastic fibre-reinforced semi space with surface stress

Roy I., Acharya D. P., Acharya S.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 4

939--957

EN

The present paper investigates the propagation of quasi longitudinal (qLD) and quasi transverse (qTD) waves in a magneto elastic fibre-reinforced rotating semi-infinite medium. Reflections of waves from the flat boundary with surface stress have been studied in details. The governing equations have been used to obtain the polynomial characteristic equation from which qLD and qTD wave velocities are found. It is observed that both the wave velocities depend upon the incident angle. After imposing the appropriate boundary conditions including surface stress the resultant amplitude ratios for the total displacements have been obtained. Numerically simulated results have been depicted graphically by displaying two and three dimensional graphs to highlight the influence of magnetic field, rotation, surface stress and fibre-reinforcing nature of the material medium on the propagation and reflection of plane waves.

2

Propagation and reflection of plane waves in a rotating magneto elastic fibre-reinforced semi space with surface stress

Roy I., Acharya D. P., Acharya S.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 4

1043--1061

EN

The present paper investigates the propagation of quasi longitudinal (qLD) and quasi transverse (qTD) waves in a magneto elastic fibre-reinforced rotating semi-in finite medium. Reflections of waves from the flat boundary with surface stress have been studied in details. The governing equations have been used to obtain the polynomial characteristic equation from which qLD and qTD wave velocities are found. It is observed that both the wave velocities depend upon the incident angle. After imposing the appropriate boundary conditions including surface stress the resultant amplitude ratios for the total displacements have been obtained. Numerically simulated results have been depicted graphically by displaying two and three dimensional graphs to highlight the in uence of magnetic field, rotation, surface stress and fibre-reinforcing nature of the material medium on the propagation and reflection of plane waves.

3

Reflection and transmission of waves from a plane interface between viscous liquid and magneto elastic solid half space with voids

Acharya D. P., Maji C.

International Journal of Applied Mechanics and Engineering

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2009

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Vol. 14, no 1

21-54

EN

This paper investigates the propagation of plane waves as well as their reflection and transmission from the plane interface which separates a viscous liquid half space and a magneto elastic solid semi infinite medium containing a distribution of void pores. From the analysis of the propagation of plane waves in a magneto elastic solid medium with voids, it is found that the longitudinal wave in a void solid medium is subject to dispersion of the general wave form. In this case, short wave and long wave approximations have been made. A 'cut of frequency', which depends upon the void parameter, exists below which one of the longitudinal waves cannot propagate at all. Amplitude and energy ratios of various reflected and transmitted waves are presented in each of the four cases when (i) a set of coupled longitudinal waves (ii) a similar set of coupled waves (iii) a transverse wave, propagating through the solid half space (iv) a longitudinal wave propagating through the viscous liquid half space, are made incident at the interface. Numerical computations are made for a specific model and results are presented graphically to highlight the modulations of these ratios due to the variation of incident angle of the incident wave. It is found that the amplitude and energy ratios of various reflected and transmitted waves are functions of angle of incidence and frequency. The effects of viscosity of the liquid, magnetic field as well as void nature of the solid medium on the amplitude and energy ratios have been analyzed from the graphical representations.

4

Reflection of longitudinal displacement plane waves from the flat boundary of a solid elastic half-space containing a distribution of void pores

Acharya D. P., Mondal A.

International Journal of Applied Mechanics and Engineering

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2008

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Vol. 13, no 3

609-625

EN

This paper investigates the problem of reflection of longitudinal displacement waves in a medium containing a distribution of void pores. It is observed that three types of waves, traveling at three distinct speeds, may exist in an elastic medium with void pores. The critical frequency has been detected. Amplitude ratios have been presented. It is found that the presence of void pores modulates the wave velocities and amplitude ratios to a considerable extent. Numerical calculations have been made and graphs are drawn to exhibit the role of void pores in the problem under consideration.

5

Effect of surface stress on magneto-elastic surface waves in finitely conducting media

Acharya D.P., Maji Ch.

Acta Geophysica

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2007

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Vol. 55, no. 4

554-576

EN

This paper deals with the investigation of the effect of surface stress and conductivity on the propagation of surface wave in isotropic, homogeneous, elastic media under the action of a primary magnetic field. Formulation of the general surface wave propagation problem has been made, and the corresponding frequency equation has been derived. Frequency equations for Rayleigh wave, surface shear wave and Stoneley wave have been deduced from that of general surface wave as special cases. The effects of surface stress and magnetic field on the wave velocities and attenuation factors of Rayleigh wave and surface shear wave are shown by numerical calculations and graphs. Some important wave velocity equations, as ob-tained by other authors, have been deduced as special cases from the wave velocity equation for Stoneley wave. It is found that the combined effect of surface stress and magnetic field modulates the wave velocity ratios and attenuation factors of Rayleigh wave and surface shear wave to a considerable extent.