Frequency-dependent attenuation in water-saturated cracked glass based on creep tests

Geophysics ◽  
2017 ◽  
Vol 82 (3) ◽  
pp. MR89-MR96 ◽  
Author(s):  
Céline Mallet ◽  
Beatriz Quintal ◽  
Eva Caspari ◽  
Klaus Holliger
Keyword(s):  
Young’S Modulus ◽  
Glass Sample ◽  
Young's Modulus ◽  
Axial Stress ◽  
Creep Tests ◽  
Crack Network ◽  
Frequency Dependent ◽  
Essential Information ◽  
Poroelastic Model ◽  
Water Saturated

We estimate attenuation at subseismic frequencies from an experimental creep test performed on a thermally cracked water-saturated glass sample. The time-dependent axial stress and strain rates are used to infer the attenuation and Young’s modulus as functions of frequency. Attenuation is characterized by a pronounced frequency dependence between [Formula: see text] and [Formula: see text]. A corresponding frequency-dependent behavior of the Young’s modulus is observed with an increase from 60 to 70 GPa, which is consistent with the measured static and ultrasonic values. These observations are interpreted as being due to fluid flow between interconnected cracks in the mesoscopic scale range. To test this hypothesis, we compare the analytical characteristic frequency for the presumed mesoscopic squirt-type flow with its experimental counterpart. We also compare the experimentally observed attenuation characteristics with results of numerical simulations. For the latter, a thin section of the cracked glass sample has been digitized to provide essential information with regard to the geometry of the crack network. Together with the known physical properties of the intact glass matrix, this then allows for deriving a first-order 2D poroelastic model for the cracked sample based on Biot’s quasi-static equations.

Experimental Study of Time-Frequency Effect of Rocks

2012 ◽  
Vol 204-208 ◽  
pp. 755-760
Author(s):  
Xin Lin Wan ◽  
Su Zhang
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Sine Wave ◽  
Intersection Point ◽  
Frequency Effect ◽  
Nonlinear Frequency ◽  
Time Frequency ◽  
Physical Mechanisms ◽  
Nonlinear Frequency Response ◽  
Water Saturated

Sine wave loading experiments are carried out on MTS for pump-oil saturated Nanjing sandstones and water saturated Dali marbles. The Young’s modulus and velocities of longitudinal wave and transverse wave increase with the frequency, and there are notable dispersions. The existence of micro defects in saturated rocks result in hysteresis at the sinusoidal loading experiments. The variation curves of instantaneous Young’s modulus with stress for loading and unloading intersect, and an “X” shape figure is obtained. As the frequency of the sinusoidal wave increases, the position of the intersection point moves to higher modulus area. Thus the modulus dispersion increases. Some physical mechanisms of nonlinear frequency response of rock are revealed. The results obtained are very important for nonlinear wave study, and the theoretical study and application of earthquake and engineering.

scholarly journals Experimental Study on Anisotropic Strength and Deformation Behavior of a Coal Measure Shale under Room Dried and Water Saturated Conditions

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
Jingyi Cheng ◽  
Zhijun Wan ◽  
Yidong Zhang ◽  
Wenfeng Li ◽  
Syd S. Peng ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Water Content ◽  
Young’S Modulus ◽  
Deformation Behavior ◽  
Young's Modulus ◽  
Triaxial Compression ◽  
Coal Measure ◽  
Anisotropic Strength ◽  
Strength And Deformation ◽  
Water Saturated

This paper presents an experimental investigation of anisotropic strength and deformation behavior of coal measure shale. The effect of two factors (i.e., anisotropy and water content) on shale strength and deformation behavior was studied. A series of uniaxial and triaxial compression tests were conducted on both room dried and water saturated samples for different lamination angles. The test results indicate that (1) the compressive strength, cohesion, internal friction angle, tangent Young’s modulus, and axial strain corresponding to the peak and residual strengths of room dried specimens exhibit anisotropic behavior that strongly depends on the orientation angle(β); (2) in comparison to the room dried samples, the compressive strength and Young’s modulus as well as the anisotropy are all reduced for water saturated specimens; and (3) the failure mechanism of the samples can be summarized into two categories: sliding along lamination and shearing of rock material, with the type occurring in a particular situation depending strongly on the lamination orientation angles with respect to the major principal stress. According to the findings, it is strongly recommended that the effect of anisotropy and water content on the strength and deformation behavior of the rock must be considered in ground control designs.

scholarly journals Analysis of Dynamic Behavior of the Finite Elastic Metamaterial-Based Structure With Frequency-Dependent Properties

2018 ◽  
Vol 140 (3) ◽  
Author(s):  
X. H. Shen ◽  
C. T. Sun ◽  
M. V. Barnhart ◽  
G. L. Huang
Keyword(s):  
Young’S Modulus ◽  
Dynamic Behavior ◽  
Wave Amplitude ◽  
Young's Modulus ◽  
Mass Density ◽  
Effective Density ◽  
Frequency Dependent ◽  
Practical Applications ◽  
Global Dynamic ◽  
Elastic Metamaterials

For practical applications of the elastic metamaterials, dynamic behavior of finite structures made of elastic metamaterials with frequency dependent properties are analyzed theoretically and numerically. First, based on a frequency-dependent mass density and Young's modulus of the effective continuum, the global dynamic response of a finite rod made of elastic metamaterials is studied. It is found that due to the variation of the effective density and Young's modulus, the natural frequency distribution of the finite structure is altered. Furthermore, based on the spectral approach, the general wave amplitude transfer function is derived before the final transmitted wave amplitude for the finite-layered metamaterial structure with decreasing density is obtained using the mathematical induction method. The analytical analysis and finite element solutions indicate that the increased transmission wave displacement amplitude and reduced stress amplitude can be controlled by the impedance mismatch of the adjacent layers of the layered structure.

EFFECT OF PORE FLUIDS ON THE ELASTIC PROPERTIES OF SANDSTONE

Geophysics ◽  
1960 ◽  
Vol 25 (2) ◽  
pp. 433-444 ◽  
Author(s):  
R. L. Mann ◽  
I. Fatt
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Elastic Moduli ◽  
Young's Modulus ◽  
Clay Content ◽  
Poisson's Ratio ◽  
Statistical Validity ◽  
Bulk Compressibility ◽  
Water Saturated

Bulk compressibility, Young’s modulus, and Poisson’s ratio were measured on three sandstones. Measurements were made on both dry and water saturated samples. Several runs were made on each sandstone to establish the statistical validity of the differences observed between the wet and dry samples. Bulk compressibility of wet sandstone was 10 to 30 percent greater than for dry. Young’s modulus was 8 to 20 percent less for wet sandstone, and Poisson’s ratio was 100 percent greater on one type of sandstone when wet and only slightly greater or about the same on wet samples of the others. A high clay content is believed to lead to a large effect of water on the elastic moduli of sandstone.

scholarly journals Discrepancy between measured dynamic poroelastic parameters and predicted values from Wyllie’s equation for water-saturated Istebna sandstone

2021 ◽  
Author(s):  
Dariusz Knez ◽  
Herimitsinjo Rajaoalison
Keyword(s):  
Young’S Modulus ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Laboratory Data ◽  
Confining Pressure ◽  
P Wave ◽  
Poisson's Ratio ◽  
Rock Properties ◽  
Biot’S Coefficient ◽  
Water Saturated

AbstractThe drilling-related geomechanics requires a better understanding of the encountered formation properties such as poroelastic parameters. This paper shows set of laboratory results of the dynamic Young’s modulus, Poisson’s ratio, and Biot’s coefficient for dry and water-saturated Istebna sandstone samples under a series of confining pressure conditions at two different temperatures. The predicted results from Wyllie’s equation were compared to the measured ones in order to show the effect of saturation on the rock weakening. A negative correlation has been identified between Poisson’s ratio, Biot’s coefficient and confining pressure, while a positive correlation between confining pressure and Young’s modulus. The predicted dynamic poroelastic rock properties using the P-wave value from Wyllie’s equation are different from measured ones. It shows the important influence of water saturation on rock strength, which is confirmed by unconfined compressive strength measurement. Linear equations have been fitted for the laboratory data and are useful for the analysis of coupled stress and pore pressure effects in geomechanical problems. Such results are useful for many drilling applications especially in evaluation of such cases as wellbore instability and many other drilling problems.

Static and dynamic Young’s moduli of chalk from the North Sea

Geophysics ◽  
2008 ◽  
Vol 73 (2) ◽  
pp. E41-E50 ◽  
Author(s):  
Casper Olsen ◽  
Helle Foged Christensen ◽  
Ida L. Fabricius
Keyword(s):  
Young’S Modulus ◽  
North Sea ◽  
Strain Gauge ◽  
Young's Modulus ◽  
Displacement Transducer ◽  
Dynamic Young’S Modulus ◽  
Young’S Moduli ◽  
Static Young’S Modulus ◽  
Dynamic Young's Modulus ◽  
Water Saturated

We present results from a study of dynamic and static Young’s moduli of North Sea chalk based on laboratory tests on both dry and water-saturated chalk. We obtained static moduli by using both strain gauge and linear voltage displacement transducer (LVDT) measurements. We investigated the influence of pore fluid on static and dynamic Young’s moduli and evaluated the two methods for obtaining static Young’s modulus. We obtained good agreement between dynamic and static Young’s moduli from strain gauge measurements on dry chalk, but for water-saturated chalk the dynamic Young’s modulus was larger than the measured static Young’s modulus. This difference may be caused in part by the influence of the difference in frequencies of static and dynamic measurements. Another reason for the observed difference may be a practical experimental problem that causes the measured static Young’s modulus for water-saturated chalk to be lower than the true modulus. When we compared dynamic Young’s modulus for dry chalk with that for water-saturated chalk, the dry modulus was larger than the water-saturated modulus, probably owing to shear weakening of the chalk. Young’s modulus from LVDT measurements does not relate to dynamic Young’s modulus for dry or water-saturated rock because the LVDT is not able to accurately measure the small deformations of the samples during loading at relatively low stresses.

Ultrasonic characterization of the complex Young’s modulus of polymer parts fabricated with microstereolithography

2018 ◽  
Vol 24 (7) ◽  
pp. 1193-1202 ◽  
Author(s):  
Clinton B. Morris ◽  
John M. Cormack ◽  
Mark F. Hamilton ◽  
Michael R. Haberman ◽  
Carolyn C. Seepersad
Keyword(s):  
Dynamic Response ◽  
Young’S Modulus ◽  
Material Properties ◽  
Dynamic Modulus ◽  
Young's Modulus ◽  
Ultrasonic Waves ◽  
Frequency Dependent ◽  
Content Type ◽  
Material Parameters ◽  
Complex Young’S Modulus

Purpose Microstereolithography is capable of producing millimeter-scale polymer parts having micron-scale features. Material properties of the cured polymers can vary depending on build parameters such as exposure. Current techniques for determining the material properties of these polymers are limited to static measurements via micro/nanoindentation, leaving the dynamic response undetermined. The purpose of this paper is to demonstrate a method to measure the dynamic response of additively manufactured parts to infer the dynamic modulus of the material in the ultrasonic range. Design/methodology/approach Frequency-dependent material parameters, such as the complex Young’s modulus, have been determined for other relaxing materials by measuring the wave speed and attenuation of an ultrasonic pulse traveling through the materials. This work uses laser Doppler velocimetry to measure propagating ultrasonic waves in a solid cylindrical waveguide produced using microstereolithography to determine the frequency-dependent material parameters of the polymer. Because the ultrasonic wavelength is comparable with the part size, a model that accounts for both geometric and viscoelastic dispersive effects is used to determine the material properties using experimental data. Findings The dynamic modulus in the ultrasonic range of 0.4-1.3 MHz was determined for a microstereolithography part. Results were corroborated by using the same experimental method for an acrylic part with known properties and by evaluating the natural frequency and storage modulus of the same microstereolithography part with a shaker table experiment. Originality/value The paper demonstrates a method for determining the dynamic modulus of additively manufactured parts, including relatively small parts fabricated with microstereolithography.

A study of the anisotropic static and dynamic elastic properties of transversely isotropic rocks

Geophysics ◽  
2019 ◽  
Vol 84 (6) ◽  
pp. C281-C293 ◽  
Author(s):  
Fei Gong ◽  
Bangrang Di ◽  
Jianxin Wei ◽  
Pinbo Ding ◽  
He Tian ◽  
...  
Keyword(s):  
Young’S Modulus ◽  
Clay Minerals ◽  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Dynamic Properties ◽  
Axial Stress ◽  
Poisson's Ratio ◽  
Static Young’S Modulus ◽  
Loading And Unloading

The elastic properties of rock are major factors affecting hydraulic fracturing. Static elastic properties can be estimated using geomechanical laboratory tests, whereas dynamic properties can be estimated from elastic-wave velocity and rock density. We prepared two synthetic shales containing different clay minerals and one natural shale and focused on the elastic properties for the full tensor of elasticity and their anisotropy. The static and dynamic properties of these dry samples were obtained based on triaxial tests during loading and unloading. The results suggest that the synthetic and natural shale indicate high similarity in the static and dynamic properties. The dynamic Young’s modulus and Poisson’s ratio increase with increasing axial stress during loading and unloading. For the static properties, the static Poisson’s ratio increases with axial stress during loading and unloading. However, differences exist between the static and dynamic Young’s moduli during loading, with the static Young’s modulus decreases with the increasing axial stress at a high stress level. In addition, the static Young’s modulus is consistently lower than the dynamic Young’s modulus during loading and unloading, but the static Poisson’s ratio is larger or smaller than the dynamic Poisson’s ratio. During loading and unloading, there could be approximately a 30% difference when estimating static elastic properties from the static-dynamic relations, depending on which static moduli are used. Furthermore, the static and dynamic properties of the samples are strongly anisotropic, and the anisotropy of elastic properties is sensitive to the axial stress and the clay minerals.

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