scholarly journals Experimental Study on Mechanical Properties, Energy Dissipation Characteristics and Acoustic Emission Parameters of Compression Failure of Sandstone Specimens Containing En Echelon Flaws

2019 ◽  
Vol 9 (3) ◽  
pp. 596 ◽  
Author(s):  
Dongming Zhang ◽  
Shujian Li ◽  
Xin Bai ◽  
Yushun Yang ◽  
Yapei Chu
Keyword(s):  
Mechanical Properties ◽  
Acoustic Emission ◽  
Energy Dissipation ◽  
Warning Signal ◽  
Video Camera ◽  
Likelihood Method ◽  
Acoustic Emission Energy ◽  
Emission Energy ◽  
Compression Failure ◽  
Precursor Information

To further understand the fracture behavior of rock materials containing en echelon flawsand determine precursor information for the final collapse of damaged mineral assemblies undercompression, a series of uniaxial compression experiments using a loading system, an acousticemission system and a video camera was conducted on sandstone specimens containing en echelonflaws. The mechanical properties, energy dissipation characteristics and acoustic emissionparameters of compression failure of selected specimens were successively analyzed. The resultsshowed that crack initiation was accompanied by a stress drop, step-like characteristics on theenergy consumption curve and increased crackling noises, which were used as early warningsignals before the final collapse happened. In addition, we used the histogram statistics methodand maximum likelihood method to analyze the distribution of acoustic emission energy anddetermined that the acoustic emission energy distributions of sandstone specimens containing enechelon flaws followed a power law. With the progress of the experiment, the optimum exponentschanged in different stages and gradually decreased as failure was approached, which could alsobe used as an early warning signal before the final collapse happened. This paper may providesome theoretical basis for monitoring and warning about the collapse and instability of engineeringrock masses containing en echelon flaws.

scholarly journals Study on Multiparameter Precursory Information Identification of the Fracture of Yellow Sandstone

2019 ◽  
Vol 2019 ◽  
pp. 1-15 ◽  
Author(s):  
Xiao Fukun ◽  
Wang Houran ◽  
Liu Gang
Keyword(s):  
Acoustic Emission ◽  
Early Warning ◽  
High Frequency ◽  
Damage Evolution ◽  
Average Frequency ◽  
Acoustic Emission Energy ◽  
Emission Energy ◽  
Acoustic Emission Count ◽  
Precursor Information ◽  
Precursory Information

In order to explore the disaster caused by uncontrollable instability of coal and rock mass, a multiparameter fusion system is constructed to predict and predict disasters more accurately by identifying the mechanical and acoustic precursors of coal and rock fracture. In order to explore the precursor information of yellow sandstone rupture, the damage evolution process of yellow sandstone is analyzed from the four aspects of rock mechanics, acoustic emission time domain, frequency domain, and characteristic parameters, and the body strain, dissipated energy and acoustic emission counting, acoustic emission energy, average frequency, peak frequency, b value, and entropy value precursor information identification points are obtained, and 8 parameters are analyzed by time series fusion. The specific conclusions are as follows: body strain in the violent stage of damage evolution, the slope is zero, the zero end point is the precursor information identification point, the dissipative energy curve overall shows the “s” type, the early growth rate is faster—the medium-term stability—the later period is slowed down, and the upper slope boundary point of the “s” type curve is used as the precursor information identification point. In the violent stage of damage evolution, the layered features of the acoustic emission count are obvious, the specific gravity shift is more obvious, and the high count appears as the precursor information identification point; the acoustic emission energy accumulates the high-energy signal and is accompanied by the steady and rapid growth of energy as the precursor information identification point. The effects of shearing main cracks, shear microcracks, tensile cracks, and composite cracks on the acoustic emission count and energy in the damage evolution process are analyzed. The increase of medium- and high-frequency signals and the reduction of high-frequency signals predict the rupture. The average frequency signal change law is continuous high frequency-blank-continuous high frequency, with the blank period end point as the damage precursor identification point; the b value damage evolution stage shows a continuously steady increase to a rapid increase, with the continuous stable growth starting point as the crack identification point. In the process of damage evolution, the sample entropy presents an orderly, chaotic, disordered, and orderly process. The end of chaos and the beginning of disorder are used as the prejudging demarcation points. Based on the time sequence, an eight-parameter comprehensive early warning system is constructed. The indicators are classified into five levels for early warning in the stage of severe damage evolution. The identification of multiparameter precursory information of yellow sandstone provides a new research idea and analysis angle and method for the failure of other coal and rock masses.

Acoustic emission energy relates to bond strength

1975 ◽  
Vol 8 (5) ◽  
pp. 249-257 ◽  
Author(s):  
G.J. Curtis
Keyword(s):  
Acoustic Emission ◽  
Bond Strength ◽  
Acoustic Emission Energy ◽  
Emission Energy

Subcritical Fracturing of Sandstone Characterized by the Acoustic Emission Energy

2019 ◽  
Vol 52 (7) ◽  
pp. 2459-2469 ◽  
Author(s):  
Yuekun Xing ◽  
Guangqing Zhang ◽  
Bin Wan ◽  
Hui Zhao
Keyword(s):  
Acoustic Emission ◽  
Acoustic Emission Energy ◽  
Emission Energy

scholarly journals Acoustic emission energy to pulse height converter

1973 ◽  
Author(s):  
B.W. Speller
Keyword(s):  
Acoustic Emission ◽  
Pulse Height ◽  
Acoustic Emission Energy ◽  
Emission Energy
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