scholarly journals Mechanical Behavior of Frozen Porous Sandstone under Uniaxial Compression

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Hong-Ying Wang ◽  
Qiang Zhang
Keyword(s):  
Tensile Strength ◽  
Longitudinal Wave ◽  
Uniaxial Compression ◽  
Wave Velocity ◽  
Compression Strength ◽  
Peak Strain ◽  
Secant Modulus ◽  
Longitudinal Wave Velocity ◽  
Uniaxial Compression Strength ◽  
Porous Sandstone

The influence of low temperature on longitudinal wave velocity, uniaxial compression strength, tensile strength, peak strain, secant modulus, and acoustic emission characteristics of yellow sandstones was studied. The results show that the secant modulus increases with decreasing temperature when the axial strain is less than 0.6%, and a contrary influence performs for the subsequent stage due to the fracture of the pore ice. With the decrease in temperature, the uniaxial compression strength first increases and then remains at a relatively constant value of 34.44 MPa at about -40°C while the temperature ranges from -40°C to -70°C. The tensile strength shows an approximate linear increment as the temperature. The peak strain gradually increases with temperature in a three-stage piecewise linear form, and the increasing rate gradually decreases with the decreasing temperature. The phase transformation from liquid water at a temperature of 20°C to solid ice at a temperature of -3°C significantly increases the longitudinal wave velocity from 1.55 km/s to 3.36 km/s. When the temperature is lower than -10°C, the longitudinal wave velocity approximately increases linearly at a rate of 2.67 × 10 − 3   km / s · ° C − 1 with decreasing temperature.

scholarly journals Linking static and dynamic mechanical properties for metamorphic rocks from Austria including their anisotropic effect

2021 ◽  
Author(s):  
Nina Gegenhuber ◽  
Melanie Krueger
Keyword(s):  
Uniaxial Compression ◽  
Wave Velocity ◽  
Compression Strength ◽  
Dynamic Properties ◽  
Oil Industry ◽  
Economic Factor ◽  
Compressional Wave ◽  
Uniaxial Compression Strength ◽  
Geomechanical Properties ◽  
Anisotropic Effect

AbstractThe derivation of geomechanical properties from petrophysical/geophysical data is not only of great importance in the oil industry but also in mining, geothermal projects and tunnelling, for reduction of costs and to improve security. For the oil industry and geothermal sector, it is mainly important for drilling rate and the stability of the borehole and, as a result, the economic factor. A key issue is that geomechanical properties, which can support a better planning of a project, cannot be measured in the borehole or on the surface directly. In this study, the focus is put on anisotropic effects on the correlation between static and dynamic properties, which is neglected in most studies but important because values can vary extremely. Therefore, measurements in the geotechnical laboratory of compressional and shear wave velocity during uniaxial compression strength test were taken. Additionally, typical properties like bulk and grain density as well as porosity were determined too. Different samples (carbonate–silica schist, marble and phyllite) from the "Zentrum am Berg"-research tunnelling centre at the "Erzberg" in Austria were used. Shown are correlations between uniaxial compression strength and compressional wave velocity as well as for static and dynamic Young’s modulus including their anisotropic effect. The results are promising and provide an opportunity for further applications on log data.

Determining the Thermal Shock Elastic Behavior of Mullite Ceramic Regenerator Material by Ultrasonic Testing

2014 ◽  
Vol 633 ◽  
pp. 472-475 ◽  
Author(s):  
Tian Tian Sun ◽  
Yan Xia Wang ◽  
Hai Yun ◽  
Dong Huan Zhang ◽  
Qing Hui Shang
Keyword(s):  
Thermal Shock ◽  
Longitudinal Wave ◽  
Shear Wave ◽  
Wave Velocity ◽  
Temperature Difference ◽  
Shear Wave Velocity ◽  
Modulus Of Elasticity ◽  
Longitudinal Wave Velocity ◽  
Mullite Ceramic ◽  
Mullite Ceramics

Mullite material is a material commonly used in honeycomb regenerator, because in the process of using material under big temperature difference effect, so have a great demand for its thermal shock resistance. The used mullite ceramics were made by the direct solid phase sintering method, and the modulus of elasticity of the mullite ceramics measured by ultrasonic pulse-echo method in a thermal shock and thermal fatigue experiment, respectively. In the air-cooling condition, the study found the mullite ceramic without thermal shock that the longitudinal wave velocity and shear wave velocity respectively 3970(m/s) and 2492(m/s). After 45 times thermal shock of temperature difference of 800°C, longitudinal wave velocity and shear wave velocity decreased to 3910(m/s) and 2457(m/s), and the value of the modulus of elasticity changed 1020MPa. By observing the change of the elastic modulus value rule, can know the elastic deformation of thermal shock on the material performance of thermal shock damage. Moreover, the results can provide the data basis for the calculation of the residual strength and the numerical simulation of thermal stress.

Ultrasonic Study on Crystal Orientation Effects Upon Point Defect Growth Caused by Cross Slip Under Plastic Deformation

2004 ◽  
Author(s):  
Michiaki Kobayashi
Keyword(s):  
Plastic Deformation ◽  
Longitudinal Wave ◽  
Wave Velocity ◽  
Crystal Orientation ◽  
Pure Shear ◽  
Cross Slip ◽  
Polished Surface ◽  
Longitudinal Wave Velocity ◽  
Velocity Change ◽  
Change Tendency

Concerned with the longitudinal wave velocity changes under plastic deformation in pure shear state, the experimental results of longitudinal wave velocity are categorized to two types: (i) simple decreasing change tendency at polished surface specimens, and (ii) chaotic change tendency at unpolished surface specimens. In the present paper, the effects of surface roughness and crystal orientation on the amount of cross slip under plastic deformation are studied via finite element polycrystal model (FEPM) from the viewpoint of longitudinal wave velocity change showing a sensitive response to the point defects caused by cross slip.

Monitoring of Longitudinal-Wave Velocity and Attenuation of SrTiO3at Low Temperatures Using Picosecond Ultrasound Spectroscopy

2012 ◽  
Vol 51 (7S) ◽  
pp. 07GA09 ◽  
Author(s):  
Akira Nagakubo ◽  
Akihiro Yamamoto ◽  
Kenichi Tanigaki ◽  
Hirotsugu Ogi ◽  
Nobutomo Nakamura ◽  
...  
Keyword(s):  
Longitudinal Wave ◽  
Wave Velocity ◽  
Low Temperatures ◽  
Longitudinal Wave Velocity
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