Excitation mechanisms and dispersion characteristics of guided waves in multilayered cylindrical solid media

2012 ◽  
Vol 131 (3) ◽  
pp. 2048-2062 ◽  
Author(s):  
Hanyin Cui ◽  
Bixing Zhang ◽  
Sherri Johnstone ◽  
Jon Trevelyan
Keyword(s):  
Guided Waves ◽  
Dispersion Characteristics ◽  
Solid Media ◽  
Cylindrical Solid ◽  
Excitation Mechanisms

Stoneley waves in three-layered cylindrical solid media

2011 ◽  
Vol 130 (1) ◽  
pp. EL44-EL49 ◽  
Author(s):  
Hanyin Cui ◽  
Jon Trevelyan ◽  
Sherri Johnstone
Keyword(s):  
Stoneley Waves ◽  
Solid Media ◽  
Cylindrical Solid

ELECTROMAGNETIC GUIDED WAVES IN A METAMATERIAL-MAGNETIC WAVEGUIDE STRUCTURE

2011 ◽  
Vol 25 (32) ◽  
pp. 4543-4551 ◽  
Author(s):  
H. M. MOUSA ◽  
M. M. SHABAT
Keyword(s):  
Guided Waves ◽  
Waveguide Structure ◽  
Negative Permittivity ◽  
Physical Parameters ◽  
Dispersion Characteristics ◽  
Permittivity And Permeability ◽  
Magnetic Waveguide ◽  
And Behavior

The growing and rapid interest in new artificial metamaterials, whose properties differ from the normal materials has motivated further investigations. The metamaterials have simultaneously negative permittivity and permeability. In this work, we have demonstrated theoretically the existence and behavior of the TE guided waves in a ferromagnetic/metamaterial/antiferromagnetic waveguide structure. The dispersion characteristics are performed for different kinds of metamaterials. The existence and the type of the solutions to the guided waves with respect to different physical parameters are also investigated and discussed. It has been shown that the metamaterials can lead to different, new unusual properties.

Elastic Wave Propagation in Laminated Composite Plates

1991 ◽  
Vol 113 (4) ◽  
pp. 411-418 ◽  
Author(s):  
W. M. Karunasena ◽  
R. L. Bratton ◽  
S. K. Datta ◽  
A. H. Shah
Keyword(s):  
Analytical Method ◽  
Guided Waves ◽  
Laminated Composite ◽  
Composite Plates ◽  
Thickness Variation ◽  
Dispersion Characteristics ◽  
Laminated Plate ◽  
Laminated Composite Plates ◽  
Number Of Layers ◽  
Stiffness Method

A stiffness method and an analytical method have been used to study the dispersion characteristics of guided waves in laminated composite plates. Both cross-ply and angle-ply plates have been considered in the analysis. The objective of the study is to analyze the effect of fiber orientation, ply layout configuration, and number of layers on the dispersion characteristics. A Rayleigh-Ritz type of approximation of the through-thickness variation of the displacements that maintain continuity of displacements and tractions at the interfaces between the layers has been used in the stiffness method. The analytical method solves the exact dispersion relation of the laminated plate by using the Muller’s method with initial guesses obtained through the stiffness method. Both methods are applicable to plates with arbitrary number of layers having distinct mechanical properties. Numerical results presented show strong influence of anisotropy on the guided waves.

Elastic wave propagation in a fluid‐filled borehole and synthetic acoustic logs

Geophysics ◽  
1981 ◽  
Vol 46 (7) ◽  
pp. 1042-1053 ◽  
Author(s):  
Chuen Hon Cheng ◽  
M. Nafi Toksöz
Keyword(s):  
Wave Propagation ◽  
Elastic Wave ◽  
Decay Rate ◽  
Elastic Waves ◽  
Guided Waves ◽  
Effective Radius ◽  
Dispersion Characteristics ◽  
Stoneley Waves ◽  
Full Wave ◽  
Shale Formation

The propagation and dispersion characteristics of guided waves in a fluid‐filled borehole are studied using dispersion curves and modeling full‐wave acoustic logs by synthetic microseismograms. The dispersion characteristics of the pseudo‐Rayleigh (reflected) and Stoneley waves in a borehole with and without a tool in the center are compared. Effects of different tool properties are calculated. The effect of a rigid tool is to make the effective borehole radius smaller. As an approximation, dispersion characteristics of the guided waves in a borehole with a tool can be calculated as a purely fluid‐filled borehole with a smaller effective radius. Theoretical waveforms (microseismograms) of elastic waves propagating in a borehole are calculated using a discrete wavenumber integration. With an appropriate choice of parameters, our results look similar to the acoustic waveforms recorded in a limestone and a shale formation. Several factors affect the shape of an acoustic log microseismogram. The effective radius of the borehole determines the relative amplitudes of the modes generated. Poisson’s ratio of the formation is the primary factor determining the relative amplitude of the leaky mode following the compressional arrival. Attenuation affects the duration and decay rate of the guided waves.

Sign in / Sign up

Export Citation Format

Share Document