scholarly journals Determination of elastic parameters of grain with oedometric and acoustic methods

2012 ◽  
Vol 49 (No. 2) ◽  
pp. 56-60 ◽  
Author(s):  
M. Stasiak
Keyword(s):  
Hydrostatic Pressure ◽  
Moisture Content ◽  
Shear Wave ◽  
Equilibrium Moisture Content ◽  
Shear Wave Velocity ◽  
Modulus Of Elasticity ◽  
Uniaxial Compression Test ◽  
Elastic Parameters ◽  
Acoustic Methods

Values of modulus of elasticity E and Poisson’s ratio   were determined with two methods adopted from geotechnique. First approach used was a method proposed by Sawicki (1994). This type of examination was applied to estimate values of E and v for wheat and rapeseed beddings for five levels of moisture content ranging from 6% to 20%. Modulus of elasticity E of wheat was found to decrease with an increase in moisture content. With the second method values of E were determined based on measurement of shear wave velocity. Tests were performed for bedding of wheat and rapeseed under equilibrium moisture content. Values of modulus of elasticity were found to depend of hydrostatic pressure and were higher then those determined in uniaxial compression test.

Shear Strength Monitoring System Based on Measurement of Shear Wave Velocity and Moisture Content

2014 ◽  
Vol 635-637 ◽  
pp. 750-754
Author(s):  
Peng Hu ◽  
Qing Li ◽  
Yi Wei Xu ◽  
Nan Ying Shentu ◽  
Quan Yuan Peng
Keyword(s):  
Shear Strength ◽  
Moisture Content ◽  
Shear Wave ◽  
Monitoring System ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Bender Elements ◽  
Strength Measurement ◽  
Soil Shear Strength ◽  
The Relationship

Expound the importance of soil shear strength measurement at mudslide hidden point to release the loss caused by the disaster, explain the relationship between shear wave velocity, moisture content and shear strength, design the shear strength monitoring system combining the shear wave velocity measured by Piezoelectric bender elements and moisture content.

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.

Pre-grading of spruce logs containing frozen and unfrozen water by means of frequency-based nondestructive testing (NDT)

Holzforschung ◽  
2016 ◽  
Vol 70 (1) ◽  
pp. 79-85 ◽  
Author(s):  
Julia K. Denzler ◽  
Andreas Weidenhiller
Keyword(s):  
Nondestructive Testing ◽  
Moisture Content ◽  
Industrial Application ◽  
Modulus Of Elasticity ◽  
Dynamic Modulus ◽  
The State ◽  
Temperature Measurements ◽  
Unfrozen Water ◽  
State Of Matter

AbstractThe possibility for pre-grading of logs throughout the year has been evaluated based on dynamic modulus of elasticity (MOEdynor simplifiedEdyn) by means of frequency-based nondestructive testing (NDTfreq). The challenge is thatEdynis variable in the frozen, partly frozen, and unfrozen states of logs (state of matter). In the unfrozen state, NDTfreqis reliable if the moisture content does not fall below fiber saturation. The state of the matter was tested via temperature measurements of air and log by means of an infrared technique and sensors, and information was evaluated from NDTfreq. The temperature measurements proved to be inefficient for industrial application because of unreliable data and long measurement times, whereas the NDTfreqmeasurements allowed the determination of meaningful damping factors. A sufficient level of predictability for more than 60% of the measurements was found. The log measurements in the partly frozen state are inconclusive becauseEdyndata fluctuate in the presence of both liquid and frozen water. For the completely frozen logs, a correction is introduced as a precaution that avoids an overestimation ofEdynin the unfrozen state.

Measuring shear and compression wave velocities of soil using bender–extender elements

2009 ◽  
Vol 46 (7) ◽  
pp. 792-812 ◽  
Author(s):  
E. C. Leong ◽  
J. Cahyadi ◽  
H. Rahardjo
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Compression Wave ◽  
Small Strain ◽  
Reliable Determination ◽  
Digital Oscilloscope ◽  
Compression Waves ◽  
Wave Velocities

Piezoceramic elements have been used for laboratory measurement of wave velocity in soil and rock specimens. Shear-wave piezoceramic elements (bender elements) are commonly used to measure shear wave velocity for the determination of small-strain shear modulus. Compression-wave piezoceramic elements (extender elements), on the other hand, are less commonly used as compression wave velocity is less frequently measured. In this paper, the performance of a pair of bender–extender elements for the determination of both shear and compression wave velocities is examined with respect to the resolution of the recorder, bender–extender element size. and excitation voltage frequency. The evaluation showed that the performance of the bender–extender elements test can be improved by considering the following conditions: (i) the digital oscilloscope used to record the bender–extender element signals should have a high analog to digital (A/D) conversion resolution; (ii) the size of the bender–extender elements plays an important role in the strength and quality of the receiver signal, especially for compression waves; and (iii) using a wave path length to wavelength ratio of 3.33 enables a more reliable determination of shear wave velocity.

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