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.

scholarly journals On the identification of the eggshell elastic properties under quasistatic compression

2004 ◽  
Vol 52 (5) ◽  
pp. 73-82 ◽  
Author(s):  
Jana Simeonovová ◽  
Jaroslav Buchar
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Elastic Constants ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Rotational Shell ◽  
Mutual Comparison ◽  
Quasistatic Loading

The problem of the identification of the elastic properties of eggshell, i.e. the evaluation of the Young's modulus and Poisson's ratio is solved. The eggshell is considered as a rotational shell. The experiments on the egg compression under quasistatic loading have been conducted. During these experiments a strain on the eggshell surface has been recorded. By the mutual comparison between experimental and theoretical values of strains the influence of the elastic constants has been demonstrated.

scholarly journals Thermally Tunable Dynamic and Static Elastic Properties of Hydrogel Due to Volumetric Phase Transition

Polymers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1462 ◽  
Author(s):  
Yuqi Jin ◽  
Teng Yang ◽  
Shuai Ju ◽  
Haifeng Zhang ◽  
Tae-Youl Choi ◽  
...  
Keyword(s):  
Phase Transition ◽  
Bulk Modulus ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Solution Temperature ◽  
Temperature Sensitive ◽  
Alginate Hydrogel

The temperature dependence of the mechanical properties of polyvinyl alcohol-based poly n-isopropyl acrylamide (PVA-PNIPAm) hydrogel was studied from the static and dynamic bulk modulus of the material. The effect of the temperature-induced volumetric phase transition on Young’s Modulus, Poisson’s ratio, and the density of PVA-PNIPAm was experimentally measured and compared with a non-thermo-responsive Alginate hydrogel as a reference. An increase in the temperature from 27.5 to 32 °C results in the conventional temperature-dependent de-swelling of the PVA-PNIPAm hydrogel volume of up to 70% at the lower critical solution temperature (LCST). However, with the increase in temperature, the PVA-PNIPAm hydrogel showed a drastic increase in Young’s Modulus and density of PVA-PNIPAm and a corresponding decrease in the Poisson’s ratio and the static bulk modulus around the LCST temperature. The dynamic bulk modulus of the PVA-PNIPAm hydrogel is highly frequency-dependent before the LCST and highly temperature-sensitive after the LCST. The dynamic elastic properties of the thermo-responsive PVA-PNIPAm hydrogel were compared and observed to be significantly different from the thermally insensitive Alginate hydrogel.

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.

Elastic moduli of boron nitride, aluminium nitride and gallium nitride nanotubes using second generation reactive empirical bond order potential

2015 ◽  
Vol 11 (1) ◽  
pp. 2-15 ◽  
Author(s):  
Dinesh Kumar ◽  
Veena Verma ◽  
Keya Dharamvir ◽  
H S Bhatti
Keyword(s):  
Shear Modulus ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Second Generation ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Content Type ◽  
Bond Order Potential ◽  
Rebo Potential

Purpose – The purpose of this paper is to study elastic properties of III-V nitride nanotubes (NNTs) using second generation (REBO) potential. Design/methodology/approach – In the present research paper elastic properties of BN, AlN and GaN nanotubes have been investigated, using the second generation REBO potential by Brenner and co-workers, which is a bond order potential earlier used for carbon nanostructures successfully. In the present calculation, the same form of potential is used with adjusted parameters for h-BN, h-AlN and h-GaN. In all these cases the authors have considered graphite like network and strongly polar nature of these atoms so electrostatic forces are expected to play an important role in determining elastic properties of these nanotubes. The authors generate the coordinates of nanotubes of different chirality’s and size. Each and every structure thus generated is allowed to relax till the authors obtain minima of energy. The authors then apply the requisite compressions, elongations and twists to the structures and compute the elastic moduli. Young’s Modulus, Shear Modulus and Poisson’s ratio for single-walled armchair and zigzag tubes of different chirality’s and size have been calculated. The computational results show the variation of Young’s Modulus, Poisson’s ratio and Shear Modulus for these NNTs with nanotube diameter. The results have been compared with available data, experimental as well as theoretical. Findings – The authors have calculated bond length, cohesive energy/bond, Strain energy, Young’s Modulus, Shear Modulus and Poisson’s ratio. Originality/value – To the best of the knowledge this work is the first attempt to study elastic properties of III-V NNTs using second generation REBO potential

SONIC DETERMINATION OF THE ELASTIC PROPERTIES OF ICE

1947 ◽  
Vol 25a (2) ◽  
pp. 88-95 ◽  
Author(s):  
T. D. Northwood
Keyword(s):  
Rayleigh Wave ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Elastic Waves ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
The Other ◽  
Poisson's Ratio ◽  
Wave Velocities

By measuring the velocity of various types of elastic waves in a solid it is possible to deduce Young's modulus and Poisson's ratio. Longitudinal, extensional, and Rayleigh wave velocities were measured in ice, the first by resonance in a rod and the other two by a pulsing technique. The value obtained for Young's modulus was 9.8 × 1010 dynes per cm.2 and for Poisson's ratio was 0.33.

Accurate Determination of the Elastic properties of Near Surface Regions and Thin Films Using Nanoindentation and Acoustic Microscopy

2001 ◽  
Vol 695 ◽  
Author(s):  
Matthew Bamber ◽  
Adrian Mann ◽  
Brian Derby
Keyword(s):  
Thin Films ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Elastic Constants ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Accurate Determination ◽  
Acoustic Microscopy ◽  
Poisson's Ratio ◽  
Near Surface

ABSTRACTNanoindentation has been successfully used as a mechanical properties microprobe to characterise the elastic properties of materials. However, in an isotropic material it is not possible to measure the two independent elastic constants by nanoindentation. Normally, a value of Young's modulus is determined using an assumed value for Poisson's ratio. It is also possible to use the acoustic microscope in its z-contrast mode to measure the elastic constants of a surface. This too produces a composite measurement of the elastic properties, which can be represented in terms of Young's modulus and Poisson's ratio. By using both techniques on the same sample area, it is possible to make two independent measurements of the elastic properties and thus determine both Young's modulus and Poisson's ratio. This method has been used on well-characterised bulk materials, e.g. silica glass, to demonstrate that it produces consistent results. It has also been uused to characterise thin films of TiN/NbN multilayers. These results show that, although for thin films there is a need to improve the analysis of the mechanics, the combination of nanoindentation and acoustic microscopy shows promise.

Scale effect and impact of discontinuities in the dynamic elastic constants of the Campanian chalk of Bougival (France)

2013 ◽  
Vol 184 (4-5) ◽  
pp. 347-355
Author(s):  
Róbert Porjesz ◽  
Françoise Bergerat
Keyword(s):  
Mechanical Properties ◽  
Rock Mass ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Scale Effect ◽  
Poisson’S Ratio ◽  
Young's Modulus ◽  
Poisson's Ratio ◽  
Overburden Rock

Abstract Physical properties of in situ rock mass are usually estimated from results obtained through laboratory tests on intact rock samples because the access to in situ rock may be quite challenging. This approach however raises some questions concerning the number of samples needed for reliable result, the validity of the extrapolation of the parameters from centimetre scale to a large rock mass and finally the effect of discontinuities contained in the rock mass. An underground quarry in Bougival with easy access to metre-scale pillars and the possibility to collect large number of samples has been chosen to analyse the scale effect and the anisotropy of the Campanian chalk. Different experiments have been designed to determine the dynamic elastic properties (Young’s modulus and Poisson’s ratio) based on geophysical approaches: ultrasonic measurements on laboratory samples, and “hammer” seismic measurements in situ. The static Young’s modulus and Poisson’s ratio have been determined through uniaxial compression tests on centimetre core samples. Pillars with and without visible discontinuities, as well as with various overburden rock thicknesses, have been chosen in order to analyse the possible impact of different heterogeneities on the elastic properties. Core samples of intact chalk, with 40mm to 100mm diameters, have been studied in laboratory. The high dispersion observed on the different results suggests that if only a few tests are analysed, the conclusions may not be representative. A statistical approach is more appropriate to analyse the mechanical properties of the chalk. The dynamic Young’s Modulus and Poisson’s ratio calculated from laboratory samples (centimetres) and in situ rocks (about ten metres) do not reveal any clear impact of size on these elastic properties. The presence of discontinuities has a major impact on both the dynamic Young’s modulus and Poisson’s ratio. Decreasing values of these properties have been observed where discontinuities (fractures, flints) have been detected. Finally, the overburden rock thickness above the underground quarries (from 14m to 50m) seems to have no effect on the mechanical properties; the uncertainty of the measurements, partly due to the heterogeneity of the chalk mass, is likely to be more important than the effect of load on the pillars.

Experimental investigation of the effects of clay content and compaction stress on the elastic properties and anisotropy of dry and saturated synthetic shale

Geophysics ◽  
2018 ◽  
Vol 83 (5) ◽  
pp. C195-C208 ◽  
Author(s):  
Fei Gong ◽  
Bangrang Di ◽  
Jianxin Wei ◽  
Pinbo Ding ◽  
He Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Symmetry Axis ◽  
Young's Modulus ◽  
Clay Content ◽  
Mechanical Anisotropy ◽  
Poisson's Ratio ◽  
Compaction Stress

Anisotropy in shales is an important issue in exploration and reservoir geophysics, and it has been proven extremely difficult to correlate anisotropy in natural shale by means of a single variable (in this case, clay content or compaction stress) because of the influence of multiple factors, such as water content, total organic carbon content, and complex mineral compositions. Thus, we used quartz, kaolinite, calcite, and kerogen extract as the primary materials to construct two sets of synthetic shale samples, each with a different clay content by weight and a different compaction stress. Ultrasonic experiments were conducted to investigate the anisotropy of velocity and mechanical properties in dry and saturated samples of our synthetic shales. The results reveal that the velocities decrease with clay content by weight and increase with compaction stress and that these changes are significant at low compaction stress. The velocity anisotropy of the samples increases with clay content and compaction stress due to the increasing alignment of the clay platelets. S-wave anisotropy is more sensitive to the clay content or compaction stress than P-wave anisotropy. The dynamic Young’s modulus [Formula: see text] of the samples decreases with clay content and increases with compaction stress, whereas Poisson’s ratio [Formula: see text] increases with clay content and decreases with compaction stress. Young’s modulus perpendicular to the symmetry axis is always larger than that parallel to the symmetry axis, but Poisson’s ratio perpendicular to the symmetry axis may be larger or smaller than that parallel to the symmetry axis, which indicates that mechanical properties have obvious anisotropic behavior. The elastic properties and anisotropy are also affected by fluids; the values of elastic and mechanical anisotropy parameters in saturated samples are significantly lower than those in dry samples.

Ultrasonic velocity and mechanical anisotropy of synthetic shale with different types of clay minerals

Geophysics ◽  
2018 ◽  
Vol 83 (2) ◽  
pp. MR57-MR66 ◽  
Author(s):  
Fei Gong ◽  
Bangrang Di ◽  
Jianxin Wei ◽  
Pinbo Ding ◽  
Xiao Pan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Clay Minerals ◽  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Applied Pressure ◽  
Mechanical Anisotropy ◽  
Poisson's Ratio ◽  
Velocity Anisotropy ◽  
Different Types

Clay minerals are the most abundant materials in shale. Their presence significantly influences the elastic behavior of reservoir rocks as a function of mineral type, volume, and distribution, and their orientation controls the shale’s intrinsic anisotropic behaviors. Thus, knowing the elastic properties of shale with different types of clay minerals is imperative for fully understanding the seismic properties of the reservoir. However, it is extremely difficult to measure the elastic properties of natural shale by means of a single variable (in this case, the type of clay), due to the influences of multiple factors, including water, total organic carbon content, complex mineral composition, and so on. Thus, we use quartz, clay (kaolinite, illite, and smectite), carbonate, and kerogen extract as the primary materials to construct synthetic shale with different types of clay. Ultrasonic experiments were conducted to study the anisotropy of velocity and mechanical properties (Young’s modulus and Poisson’s ratio) in dry synthetic shale samples as a function of applied axial stress. The results show that the velocity of samples increases with applied pressure and the rate of velocity increase is higher at low pressures. Similarly, the dynamic Young’s modulus and Poisson’s ratio increase with applied pressure; [Formula: see text] is always larger than [Formula: see text], but [Formula: see text] may be larger or smaller than [Formula: see text]. Furthermore, velocity anisotropy and mechanical anisotropy decrease with the increase of stress and are sensitive to stress and lithology. The closure of large aspect-ratio pores (and/or microcracks) seems to be a dominant mechanism controlling the change of anisotropy. Finally, the changes in mechanical anisotropy under applied stress are larger compared with the changes in velocity anisotropy, indicating that mechanical properties are more sensitive to the changes in rock property.

scholarly journals Elastic Properties of Thulium Doped Zinc Borotellurite Glass

2016 ◽  
Vol 863 ◽  
pp. 70-74 ◽  
Author(s):  
Laoding Hasnimulyati ◽  
Mohamed Kamari Halimah ◽  
Zakaria Azmi ◽  
Abdul Halim Shaari ◽  
Mansor Ishak
Keyword(s):  
Young’S Modulus ◽  
Elastic Properties ◽  
Poisson’S Ratio ◽  
Elastic Moduli ◽  
Young's Modulus ◽  
Longitudinal Shear ◽  
Poisson's Ratio ◽  
Melt Quenching ◽  
Ultrasound Technique ◽  
Quenching Method

A series of Tm-doped zinc borotellurite glass have been extracted by conventional melt-quenching method. The density was measured and it had been found that the value is increased by the increment of Tm3+ ion. The elastic properties of the sample were determined by measuring longitudinal and shear velocities using an ultrasound technique. Then the values inserted into equations that calculate the elastic moduli of the glass samples. These include longitudinal, shear, bulk, Young’s modulus and also the Poisson’s ratio. The longitudinal and shear velocities show an increment as Tm3+ increases from 0.01 to 0.03 mol content. The trend then changes as Tm3+ increases from 0.03 to 0.05 mol content. In terms of elastic moduli, it produces a rapid increment with Tm3+ until 0.03 mol content. But after that, the increment becomes slow until 0.05 mol of Tm3+. The value of Poisson’s ratio decreases with the addition of Tm3+ concentration.

Sign in / Sign up

Export Citation Format

Share Document