scholarly journals The Effect of High Loading Rate on the Behaviour and Mechanical Properties of Coal-Rock Combined Body

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Fengqiang Gong ◽  
Hao Ye ◽  
Yong Luo
Keyword(s):  
Incident Energy ◽  
Loading Rate ◽  
Peak Stress ◽  
High Loading ◽  
Peak Strain ◽  
Rate Range ◽  
Loading Rates ◽  
High Loading Rate ◽  
Coal Rock ◽  
Second Peak

In order to investigate the high loading rate effect on the behaviour and mechanical properties of coal-rock combined body, the dynamic compressive tests were conducted by using the Split-Hopkinson Pressure Bar (SHPB) device under the loading rate range from 2.7×105 MPa/s to 4.0×105 MPa/s. The stress-strain curves, dynamic peak stress and strain, elastic modulus, and energy distribution law of coal-rock combined body under different loading rates were analyzed and discussed. The results show that the dynamic stress-strain curves of coal-rock combined body have a double-peak feature under high loading rate range, which can be divided into the initial bearing stage, the bearing decline stage, the bearing enhance stage, and the unstable stage. The first peak stress of the coal-rock combined body is independent of the loading rate, while the dynamic compressive strength (the second peak stress) and dynamic peak strain (the second peak strain) have a strong loading rate effect and will generally increase linearly with the loading rate. The first and second elastic moduli of coal-rock combined body are not sensitive to the loading rate. With the increase of the loading rate, the incident energy and reflective energy of coal-rock combined body increase rapidly, while the change of transmitted energy is very small. The absorption energy ratio of the coal-rock combined body shows a good linear law with the incident energy under different loading rates.

scholarly journals Study of Acoustic Emission and Mechanical Characteristics of Coal Samples under Different Loading Rates

2015 ◽  
Vol 2015 ◽  
pp. 1-11 ◽  
Author(s):  
Huamin Li ◽  
Huigui Li ◽  
Baobin Gao ◽  
Dongjie Jiang ◽  
Junfa Feng
Keyword(s):  
Acoustic Emission ◽  
Elasticity Modulus ◽  
Loading Rate ◽  
Peak Stress ◽  
Test System ◽  
Strong Impact ◽  
Peak Strain ◽  
Compression Tests ◽  
Loading Rates ◽  
The Relationship

To study the effect of loading rate on mechanical properties and acoustic emission characteristics of coal samples, collected from Sanjiaohe Colliery, the uniaxial compression tests are carried out under various levels of loading rates, including 0.001 mm/s, 0.002 mm/s, and 0.005 mm/s, respectively, using AE-win E1.86 acoustic emission instrument and RMT-150C rock mechanics test system. The results indicate that the loading rate has a strong impact on peak stress and peak strain of coal samples, but the effect of loading rate on elasticity modulus of coal samples is relatively small. When the loading rate increases from 0.001 mm/s to 0.002 mm/s, the peak stress increases from 22.67 MPa to 24.99 MPa, the incremental percentage is 10.23%, and under the same condition the peak strain increases from 0.006191 to 0.007411 and the incremental percentage is 19.71%. Similarly, when the loading rate increases from 0.002 mm/s to 0.005 mm/s, the peak stress increases from 24.99 MPa to 28.01 MPa, the incremental percentage is 12.08%, the peak strain increases from 0.007411 to 0.008203, and the incremental percentage is 10.69%. The relationship between acoustic emission and loading rate presents a positive correlation, and the negative correlation relation has been determined between acoustic emission cumulative counts and loading rate during the rupture process of coal samples.

Y-TZP, Ce-TZP and as-synthesized Ce-TZP/Al2O3 materials in the development of high loading rate digital light processing formulations

2021 ◽  
Vol 47 (3) ◽  
pp. 3892-3900
Author(s):  
Sophie Cailliet ◽  
Marilyne Roumanie ◽  
Céline Croutxé-Barghorn ◽  
Guillaume Bernard-Granger ◽  
Richard Laucournet
Keyword(s):  
Loading Rate ◽  
High Loading ◽  
Digital Light Processing ◽  
High Loading Rate

Dairy Waste Treatment with Anaerobic Stationary Fixed Film Reactors

1983 ◽  
Vol 15 (8-9) ◽  
pp. 359-368 ◽  
Author(s):  
L van den Berg ◽  
K J Kennedy
Keyword(s):  
Cheese Whey ◽  
Loading Rate ◽  
Cod Removal ◽  
High Loading ◽  
Loading Rates ◽  
Dairy Wastes ◽  
Plant Waste ◽  
Fixed Film ◽  
Dairy Plant ◽  
Removal Efficiencies

Cheese whey and a dilute waste from a cheese factory with a Chemical Oxygen Demand of 66,000 and 4,000 mg (COD)/L respectively, were treated at high loading rates in 0.7 to 1.2 L downflow anaerobic stationary fixed film reactors and an upflow sludge bed reactor. In downflow stationary fixed film reactors treating cheese whey, COD removal efficiencies of 97% were achieved at a loading rate of 5 kg COD/m3/day and 92% at a maximum loading rate of 22 kg COD/m3/day. With dairy plant waste, loading rates of up to 15 kg COD/m3/day were possible with COD removal efficiencies averaging 75%, decreasing slightly with increasing loading rates. In an upflow sludge bed reactor the COD removal efficiency of dairy plant waste, decreased from 87% at 5 kg COD/m3/day to 73% at 15 kg COD/m3/day. A stationary fixed film reactor treating a skim milk powder waste (4,000 ppm) could only be operated at up to 10 kg COD/m3/day with a treatment efficiency of 72%. Methane was produced from all wastes at rates corresponding to 0.32 m3 CH4 (0°C, 1 atm) per kg COD removed. Results show that stationary fixed film reactors are capable of treating dairy wastes at high loading rates and high COD removal efficiencies.

scholarly journals Effects of High Loading Rate on Reinforced Concrete Beams

2014 ◽  
Vol 111 (3) ◽  
Author(s):  
Satadru Das Adhikary ◽  
Bing Li ◽  
Kazunori Fujikake
Keyword(s):  
Reinforced Concrete ◽  
Loading Rate ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
High Loading ◽  
High Loading Rate

scholarly journals Delamination propagation under high loading rate

2020 ◽  
Vol 253 ◽  
pp. 112734 ◽  
Author(s):  
Tianyu Chen ◽  
Christopher M. Harvey ◽  
Simon Wang ◽  
Vadim V. Silberschmidt
Keyword(s):  
Loading Rate ◽  
High Loading ◽  
High Loading Rate ◽  
Delamination Propagation

Experimental Research on Acoustic Emission of Granite under Uniaxial Compression and Splitting Tensile

2012 ◽  
Vol 232 ◽  
pp. 24-27
Author(s):  
Zong Zhan Li ◽  
Jun Lin Tao ◽  
Yi Li
Keyword(s):  
Compressive Strength ◽  
Acoustic Emission ◽  
Uniaxial Compression ◽  
Uniaxial Compressive Strength ◽  
Loading Rate ◽  
Testing Machine ◽  
Peak Stress ◽  
Uniaxial Compression Test ◽  
Peak Strain ◽  
Ae Energy

This paper makes the acoustic emission of granite under uniaxial compression and splitting tensile test by electro-hydraulic testing machine and AE .We studied the relationship of uniaxial compressive strength and splitting tensile strength with the loading rate and AE characteristics of granite .The results show that uniaxial compressive strength and peak strain raise with loading rate, the AE energy gradually increases and get maximum in the 30% of the peak stress in the process of uniaxial compression test, and in the splitting tensile AE energy generates in the initial loading and gets maximum when the granite brittle fracture.

Dynamic Simulation of Crack Propagation with Dislocation Emission and Migration

1995 ◽  
Vol 408 ◽  
Author(s):  
N. Zacharopoulos ◽  
D. J. Rolovitz ◽  
R. A. Lesar
Keyword(s):  
Crack Propagation ◽  
Crack Growth ◽  
Dynamic Simulation ◽  
Loading Rate ◽  
High Loading ◽  
Spatial Evolution ◽  
Dislocation Emission ◽  
Loading Rates ◽  
Simulation Procedure ◽  
And Migration

AbstractWe present a simulation procedure for fracture that self-consistently accounts for dislocation emission, dislocation migration and crack growth. We find that the dislocation microstructure in front of the crack tip is highly organized and shows a complex temporal-spatial evolution. The final dislocation microstructure and the number of emitted dislocations immediately proceeding fracture varies rapidly with the loading rate. For high loading rates, fracture occurs at smaller loads with increasing loading rate. However, the load at fracture shows a maximum with respect to loading rates.

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