scholarly journals Effect of mechanical relaxation time in elastic materials with voids

2019 ◽  
Vol 19 (2) ◽  
pp. 51-58
Author(s):  
R. Lianngenga ◽  
L. Thangmawia
Keyword(s):  
Relaxation Time ◽  
Phase Speed ◽  
Plane Boundary ◽  
Mechanical Relaxation ◽  
Elastic Materials ◽  
Attenuation Coefficients ◽  
Reflected Waves ◽  
Materials With Voids ◽  
Incident Waves ◽  
Elastic Materials With Voids

The effect of mechanical relaxation time in the elastic wave propagation in elastic materials with voids is investigated. The phase speed and the attenuation coefficients are obtained and observed the effect of mechanical relaxation time. The phenomenon of reflection of elastic waves due to the incident waves from a plane boundary of elastic materials with voids is studied. The amplitude and energy ratios of the reflected waves are obtained. Numerically these ratios, phase speeds and the corresponding attenuation coefficients are computed for a particular model and the effect of mechanical relaxation time is discussed.

Reflection of Longitudinal Wave in the Micropolar Elasticity with Voids

2020 ◽  
pp. 2050035
Author(s):  
R. Lianngenga ◽  
J. Lalvohbika ◽  
Lalawmpuia Tochhawng ◽  
L. P. Lalduhawma ◽  
Denghmingliani Zadeng
Keyword(s):  
Free Boundary ◽  
Longitudinal Wave ◽  
Volume Fraction ◽  
Micropolar Elasticity ◽  
Elastic Materials ◽  
Reflected Waves ◽  
Longitudinal Waves ◽  
Materials With Voids ◽  
Energy Ratios ◽  
Elastic Materials With Voids

By considering no more interaction between wryness tensor and change in voids volume fraction in the materials, the reflection problem of plane longitudinal waves at a free boundary of micropolar elastic materials with voids has been investigated. We have obtained the amplitude and energy ratios of reflected waves for the incident longitudinal wave by using appropriate boundary conditions. The effect of void parameters in the nondimensional wavenumber, amplitude and energy ratios are computed numerically for the particular material’s model.

The effect of boundaries on wave propagation in a liquid-filled porous solid: III. Reflection of plane waves at a free plane boundary (general case)

1962 ◽  
Vol 52 (3) ◽  
pp. 595-625 ◽  
Author(s):  
H. Deresiewicz ◽  
J. T. Rice
Keyword(s):  
Electromagnetic Waves ◽  
Plane Waves ◽  
Body Waves ◽  
Porous Solid ◽  
Plane Boundary ◽  
Field Equations ◽  
Attenuation Coefficients ◽  
Reflected Waves ◽  
Three Body ◽  
Analytical Expressions

abstract A general solution is derived of Biot's field equations governing small motions of a porous solid saturated with a viscous liquid. The solution is then employed to study some of the phenomena attendant upon the reflection from a plane, traction-free boundary of each of the three body waves predicted by the equations. The problem, though more complex, bears some similarity to that of electromagnetic waves in a conducting medium, in that some of the reflected waves are inhomogeneous, planes of constant amplitude not coinciding with planes of constant phase. Analytical expressions are displayed for the phase velocities, attenuation coefficients, angles of reflection and the amplitude ratios, and explicit formulas are given for the limiting cases of low and high frequencies, representing first-order corrections for porosity of the solid and viscosity of the liquid, respectively. The paper concludes with a presentation of results of numerical calculations pertinent to a kerosene-saturated sandstone.

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