Nonlocal scale effect on Rayleigh wave propagation in porous fluid-saturated materials

Purpose The purpose of study to this article is to analyze the Rayleigh wave propagation in an isotropic dry sandy thermoelastic half-space. Various wave characteristics, i.e wave velocity, penetration depth and temperature have been derived and represented graphically. The generalized secular equation and classical dispersion equation of Rayleigh wave is obtained in a compact form. Design/methodology/approach The present article deals with the propagation of Rayleigh surface wave in a homogeneous, dry sandy thermoelastic half-space. The dispersion equation for the proposed model is derived in closed form and computed analytically. The velocity of Rayleigh surface wave is discussed through graphs. Phase velocity and penetration depth of generated quasi P, quasi SH wave, and thermal mode wave is computed mathematically and analyzed graphically. To illustrate the analytical developments, some particular cases are deliberated, which agrees with the classical equation of Rayleigh waves. Findings The dispersion equation of Rayleigh waves in the presence of thermal conductivity for a dry sandy thermoelastic medium has been derived. The dry sandiness parameter plays an effective role in thermoelastic media, especially with respect to the reference temperature for η = 0.6,0.8,1. The significant difference in η changes a lot in thermal parameters that are obvious from graphs. The penetration depth and phase velocity for generated quasi-wave is deduced due to the propagation of Rayleigh wave. The generalized secular equation and classical dispersion equation of Rayleigh wave is obtained in a compact form. Originality/value Rayleigh surface wave propagation in dry sandy thermoelastic medium has not been attempted so far. In the present investigation, the propagation of Rayleigh waves in dry sandy thermoelastic half-space has been considered. This study will find its applications in the design of surface acoustic wave devices, earthquake engineering structural mechanics and damages in the characterization of materials.

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Effects of irregular topography on Rayleigh-wave propagation in surface-wave exploration

10.3997/2214-4609.201900387 ◽

2019 ◽

Author(s):

H. Yamanaka ◽

S. Miyanaga ◽

K. Chimoto

Keyword(s):

Wave Propagation ◽

Surface Wave ◽

Rayleigh Wave ◽

Irregular Topography

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Rayleigh wave propagation in intact and damaged geomaterials

International Journal of Rock Mechanics and Mining Sciences ◽

10.1016/s1365-1609(03)00012-1 ◽

2003 ◽

Vol 40 (3) ◽

pp. 377-387 ◽

Cited By ~ 13

Author(s):

M. Stavropoulou ◽

G. Exadaktylos ◽

E. Papamichos ◽

I. Larsen ◽

C. Ringstad

Keyword(s):

Wave Propagation ◽

Rayleigh Wave

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Multiple Rayleigh waves guided by the planar surface of a continuously twisted structurally chiral material

Proceedings of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rspa.2020.0314 ◽

2020 ◽

Vol 476 (2239) ◽

pp. 20200314

Author(s):

Tom G. Mackay ◽

Akhlesh Lakhtakia

Keyword(s):

Wave Propagation ◽

Free Surface ◽

Rayleigh Wave ◽

Rayleigh Waves ◽

Phase Speed ◽

Angular Frequency ◽

Planar Surface ◽

Fixed Frequency ◽

Numerical Studies ◽

Anisotropic Solid

The Stroh formalism was adapted for Rayleigh-wave propagation guided by the planar traction-free surface of a continuously twisted structurally chiral material (CTSCM), which is an anisotropic solid that is periodically non-homogeneous in the direction normal to the planar surface. Numerical studies reveal that this surface can support either one or two Rayleigh waves at a fixed frequency, depending on the structural period and orientation of the CTSCM. In the case of two Rayleigh waves, each wave possesses a different wavenumber. The Rayleigh wave with the larger wavenumber is more localized to the surface and has a phase speed that changes less as the angular frequency varies in comparison with the Rayleigh wave with the smaller wavenumber.

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Study on the small-scale effect on wave propagation characteristics of fluid-filled carbon nanotubes based on nonlocal fluid theory

Advances in Mechanical Engineering ◽

10.1177/1687814018823324 ◽

2019 ◽

Vol 11 (1) ◽

pp. 168781401882332

Author(s):

Yang Yang ◽

Wuhuai Yan ◽

Jinrui Wang

Keyword(s):

Wave Propagation ◽

Fluid Flow ◽

Carbon Nanotube ◽

Scale Effect ◽

Strain Gradient ◽

Small Scale ◽

Beam Model ◽

Governing Equations ◽

Mode Wave ◽

Fluid Theory

In this article, Timoshenko’s beam model is established to investigate the wave propagation behaviors for a fluid-conveying carbon nanotube when employing the nonlocal stress–strain gradient coupled theory and nonlocal fluid theory. The governing equations of motion for the carbon nanotube are derived. The small-scale influences induced by the nanotube are simulated by nonlocal and strain gradient effects, and the scale effect induced by fluid flow is first investigated applying nonlocal fluid theory. Numerical results obtained by solving the governing equations indicate that the nonlocal effect induced by the nanotube leads to wave damping and a decrease in stiffness, while the strain gradient effect contributes to wave promotion and an enhancement in stiffness. The scale effect caused by the inner fluid only leads to a decay for a high-mode wave since there is no influence from fluid flow on the low-mode wave. The numerical solution is validated by comparing with Monte Carlo simulation and interval analysis method.

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