MEASURING OF ELASTIC MODULI BY MEANS OF SUB-SURFACE SOUNDING METHOD

2020 ◽  
pp. 44-53
Author(s):  
A. V. Kozlov
Keyword(s):  
Elastic Moduli ◽  
Point Contact ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Surface Measurement ◽  
Longitudinal And Shear Waves ◽  
Material Sample ◽  
Dynamic Elastic Moduli ◽  
Table Data

The method of determination of elastic moduli for different materials by means of measuring of longitudinal and shear waves’ velocities is discussed in the paper. The velocities are measured by obtaining the time of flight between a pair of low frequency ultrasonic dry point contact transducers installed on the surface of the studied material sample. Factors defining the accuracy of such measurement are indicated which mainly consist of physical velocity frequency dispersion, fundamental although small differences between static and dynamic elastic moduli measurements, velocity dependence on temperature etc. Comparison between Young’s modulus and Poisson’s ratio, obtained experimentally and from table data, is given for various plastics and steel samples. It shows good agreement of different methods’ data and demonstrates the applicability of the suggested elastic moduli ultrasonic sub-surface measurement method.

Magnetic Permeability and Relaxation Frequency in High Frequency Magnetic Materials.

2001 ◽  
Vol 674 ◽  
Author(s):  
M.I. Rosales ◽  
H. Montiel ◽  
R. Valenzuela
Keyword(s):  
High Frequency ◽  
Domain Walls ◽  
Magnetocrystalline Anisotropy ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Anisotropy Constant ◽  
Relaxation Frequency ◽  
Resonance Relaxation ◽  
Frequency Behavior

ABSTRACTAn investigation of the frequency behavior of polycrystalline ferrites is presented. It is shown that the low frequency dispersion (f < 10 MHz) of permeability is associated with the bulging of pinned domain walls, and has a mixed resonance-relaxation character, closer to the latter. It is also shown that there is a linear relationship between the magnetocrystalline anisotropy constant, K1, and the relaxation frequency. The slope of this correlation depends on the grain size. Such a relationship could allow the determination of this basic parameter from polycrystalline samples.

scholarly journals Laboratory measurements of low- and high-frequency elastic moduli in Fontainebleau sandstone

Geophysics ◽  
2013 ◽  
Vol 78 (5) ◽  
pp. D369-D379 ◽  
Author(s):  
Emmanuel C. David ◽  
Jérome Fortin ◽  
Alexandre Schubnel ◽  
Yves Guéguen ◽  
Robert W. Zimmerman
Keyword(s):  
Bulk Modulus ◽  
Elastic Moduli ◽  
High Pressures ◽  
Low Frequency ◽  
Frequency Dispersion ◽  
Low Frequencies ◽  
High Frequencies ◽  
Fontainebleau Sandstone ◽  
Wave Velocities ◽  
Water Saturated

The presence of pores and cracks in rocks causes the fluid-saturated wave velocities in rocks to be dependent on frequency. New measurements of the bulk modulus at low frequencies (0.02–0.1 Hz) were obtained in the laboratory using oscillation tests carried out on two hydrostatically stressed Fontainebleau sandstone samples, in conjunction with ultrasonic velocities and static measurements, under a range of differential pressures (10–95 MPa), and with three different pore fluids (argon, glycerin, and water). For the 13% and 4% porosity samples, under glycerin- and water-saturated conditions, the low-frequency bulk modulus at 0.02 Hz matched well the low-frequency and ultrasonic dry bulk modulus. The glycerin- and water-saturated samples were much more compliant at low frequencies than at high frequencies. The measured bulk moduli of the tested rocks at low frequencies (0.02–0.1 Hz) were much lower than the values predicted by the Gassmann equation. The frequency dispersion of the P and S velocities was much higher at low differential pressures than at high pressures, due to the presence of open cracks at low differential pressures.

Attenuation of elastic waves in a cracked, fluid-saturated solid

1980 ◽  
Vol 88 (3) ◽  
pp. 547-561 ◽  
Author(s):  
A. K. Chatterjee ◽  
A. K. Mal ◽  
L. Knopoff ◽  
J. A. Hudson
Keyword(s):  
Viscoelastic Material ◽  
Elastic Waves ◽  
Elastic Moduli ◽  
Shear Waves ◽  
Elastic Solid ◽  
Attenuation Coefficients ◽  
Low Frequencies ◽  
Specific Attenuation ◽  
Dynamic Elastic Moduli

AbstractThe problem of the determination of the overall dynamic elastic moduli of an elastic solid permeated by uniformly distributed penny-shaped cracks is considered. The cracks are assumed to be filled with a viscoelastic material. The orientations of the cracks may be either parallel or perfectly random. The overall velocities as well as the specific attenuation coefficients of plane harmonic compressional and shear waves are calculated for low frequencies and dilute concentration of the cracks.

scholarly journals Experimental Determination of Static And Dynamic Elastic Moduli of Rc Slabs

2020 ◽  
Vol 23 (2) ◽  
pp. 535-545
Author(s):  
Mezgeen Ahmed ◽  
◽  
Abdulhameed Yaseen ◽  
Yaman Al-kamaki ◽  
Fouad Mohammad ◽  
...  
Keyword(s):  
Experimental Determination ◽  
Elastic Moduli ◽  
Dynamic Elastic Moduli ◽  
Rc Slabs

Variation in dynamic elastic shear modulus of sandstone upon fluid saturation and substitution

Geophysics ◽  
2003 ◽  
Vol 68 (2) ◽  
pp. 472-481 ◽  
Author(s):  
Jalal Khazanehdari ◽  
Jeremy Sothcott
Keyword(s):  
Shear Modulus ◽  
Elastic Moduli ◽  
Frequency Dispersion ◽  
Dynamic Shear Modulus ◽  
Ultrasonic Frequency ◽  
Dynamic Shear ◽  
Fluid Saturation ◽  
Dynamic Elastic Moduli ◽  
Rock Microstructure ◽  
Elastic Shear

Experimental acoustic measurements on sandstone rocks at both sonic and ultrasonic frequencies show that fluid saturation can cause a noticeable change in both the dynamic bulk and shear elastic moduli of sandstones. We observed that the change in dynamic shear modulus upon fluid saturation is highly dependent on the type of saturant, its viscosity, rock microstructure, and applied pressures. Frequency dispersion has some influence on dynamic elastic moduli too, but its effect is limited to the ultrasonic frequency ranges and above. We propose that viscous coupling, reduction in free surface energy, and, to a limited extent, frequency dispersion due to both local and global flow are the main mechanisms responsible for the change in dynamic shear elastic modulus upon fluid saturation and substitution, and we quantify influences.

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