Microscopic Investigation of Rock Direct Tensile Failure Based on Statistical Analysis of Acoustic Emission Waveforms

Zhang, Zhenghu; Ma, Keping; Li, Hua; He, Zhiliang

doi:10.1007/s00603-022-02788-w

Cited by 20 publications

(7 citation statements)

References 23 publications

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“…Where σ t is the tensile stress, εis the strain, E is Young's modulus, and D is the damage variable. According to the research by Zhang et al (2006), the relationship between the damage variable and the AE cumulative rings can be directly defined as:…”

Section: Figurementioning

confidence: 99%

Bending-damaged fracture criterion and numerical implementation of limestone beam under three-point bending test

Tian

et al. 2023

Front. Earth Sci.

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To study the characteristics of tensile cracking by rock-bending damage, the bending stress–strain curves and the cumulative ringing counts were obtained by a three-point bending test and acoustic emission (AE) monitoring of limestone beams. Based on the Lemaitre strain equivalent principle and the continuous damage theory, the bending damage variable D was defined by the AE cumulative ringing counts, and the bending crack damage evolution equation was established according to the Weibull distribution of the rock element strength. To realize the numerical test of the bending deformation, the damage variable D was used as the intermediate variable, and the specific process of damage bending stress transformation and the realization of the tensile crack criterion were secondary developed by FISH language in FLAC3D. According to the results, the central part of rock beam deforms downward under the action of bending stress, and both ends tilt up. Therefore, the bending failure begins with the tensile crack at the bottom of the rock beam and gradually extends to the compression zone. The maximum damage value is about 0.402 before the peak stress. The compressive stress in the x direction increases from the neutral layer to the top of the rock beam, and the tensile stress in the x direction increases from the neutral layer to the bottom of the rock beam. The maximum tensile stress is distributed in the center of the bottom of the specimen, where the bending effect is obvious. The stress–time curve was divided into the (Ⅰ) compaction stage, (Ⅱ) expansion stage, and (Ⅲ) penetration stage, accordingly, and the evolution of damage equation was divided into three stages: initial damage stage, slow damage stage, and accelerated damage stage. The curves of the experimental result, theoretical model prediction result, and numerical simulation result were in good agreement with each other, which indicates that the numerical simulation based on the criterion of rock damaged fracture can better reflect the bending process of rock beams under three-point bending stress.

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Section: Figurementioning

confidence: 99%

Bending-damaged fracture criterion and numerical implementation of limestone beam under three-point bending test

Tian

et al. 2023

Front. Earth Sci.

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“…The transmission function of the Wiener filter was obtained from the signal-to-noise ratio; the snoring signal after spectral subtraction will further reduce the noise after passing through this filter, which performs well in sleep snoring noise processing applications. Acoustic signal recognition and processing technology are beginning to be developed in terms of theoretical fundamental research, which indicates the feasibility of acoustic thermometry has been proven, but there is as yet no report on the application of acoustic thermometry to loose coal. , In this paper, experimental tests on the acoustic emission of loose coal bodies are carried out at a later stage, and then the acoustic propagation characteristics of the composite effect between the burning sound and the applied acoustic waves in the process of coal spontaneous combustion are studied, and the evolution characteristics for the key parameters of the superimposed acoustic waves are analyzed, in order to investigate the mutual disturbance law of the “dual-source” composite acoustic waves; the proposed acoustic wave decomposition filtering algorithm will be used to study the clutter filtering rules in combustion sound and background noise, to construct the spectral separation method between combustion sound and applied acoustic wave. Using Biot’s theory and numerical simulations, the attenuation and propagation of externally applied acoustic waves in loose coal are studied, and the influence of coal properties, porosity, and other characteristics on key parameters of acoustic waves (for example, signal distortion, propagation distance, and TOF) is examined to contribute toward the development of acoustic thermometry technologies for the detection of the different stages of the loose coal spontaneous combustion.…”

Section: Dual Source Acoustic Thermometry To Detect Fires In Loose Coalmentioning

confidence: 99%

Early Detection of Coal Spontaneous Combustion by Complex Acoustic Waves in a Concealed Fire Source

et al. 2023

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Prevention and control of coal spontaneous combustion are key to coal mining and storage. Existing technologies for the detection of coal spontaneous combustion have limitations, but coal spontaneous combustion creates some serious disasters in areas of the world where coal mining and/or storage exists. New technologies to detect coal spontaneous combustion are urgently needed to reduce the loss of life and resources. The article reviews the main techniques employed to detect coal spontaneous combustion and their advantages and disadvantages; it also reviews the good application prospect of acoustic temperature measurement technology on coal spontaneous combustion and introduces the basic principle of acoustic coal temperature measurement. The evolution of combustion sound and the propagation and attenuation of acoustic waves in quasi-porous media are discussed to form the basis for the development of acoustic thermometry technologies that can be used to accurately identify acoustic signals and temperature fields in loose coal. The concept of "single-source" coal temperature measurement to "dual-source" coal temperature measurement achieved by using combustion sound and an additional sound source device in the automatic combustion of loose coal in the mined area is discussed. The deep learning methods and correlation analyses are available to map the relationships between combustion sound, coal temperature, and sound velocity, and acquire coal temperature from dual source composite acoustic signals. The study lays the foundation for the development of acoustic thermometry technologies that have applications in different stages of combustion and applied to the early warning, prevention, and control of spontaneous combustion in coal, and it contributes to improving the environmental safety and efficiency of coal mining and storage.

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“…Zhao et al [ 9 ] through assessing the AE characteristics of sandstone under triaxial compression, revealed the relationship between the damage process and the dynamic phenomena in rocks (rapid changes in stress during the loading process). Zhang et al [ 10 ] conducted direct tensile tests, studying the spatial and temporal distribution of AE signals throughout the loading process. They analyzed the distribution and evolution patterns of the normalized applied stress in AE waveform main frequencies.…”

Section: Introductionmentioning

confidence: 99%

Acoustic emission characteristic of sandstone and sandstone like material under multi-path loading

Zhuang,

Peng,

Zhao

et al. 2024

PLoS ONE

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Using spline interpolation to select proportions of similar materials, a comparative analysis of the fracturing behavior of sandstone specimens and similar material specimens was conducted through Brazilian splitting tests under multi-path loading. The study revealed that during stepwise loading, both sandstone and similar materials exhibited memory effects and plastic deformation. However, under constant velocity loading, the relationship between force and displacement in sandstone showed linearity after compaction. Employing MATLAB optimization algorithms for the inversion of acoustic emission event information, the distribution of fracture points, and the evolution of cracks were analyzed. The findings indicated that under stepwise loading, both sandstone and similar materials exhibited banded distribution of peak frequencies, with sandstone concentrated in the mid-low-frequency range and similar materials leaning towards the low-frequency range. The amplitude-frequency characteristics of acoustic emission signals suggested that initially, sandstone produced low-frequency, low-amplitude signals. As cracks developed, these signals gradually transformed into high-frequency, high-amplitude signals, ultimately leading to macroscopic failure. The ringing counts and b-values of sandstone displayed an approximate "W" shape distribution, with a subsequent decrease in b-values during final failure. In contrast, the acoustic emission counts were inversely related to b-values. Similar materials exhibited slightly more acoustic emission counts than sandstone, with relatively lower b-values. The crack development process of both sandstone and similar materials was confirmed through these observations. From the perspective of section initiation and local damage, sandstone and similar materials exhibited similar failure characteristics. The proportions of quartz sand: cement: water = 9:1:0.9 in similar materials demonstrated the most similar characteristics to sandstone in terms of mechanical loading, acoustic emission features, and failure morphology. This suggests that these similar materials can be used as substitutes for sandstone in analogous simulation experiments. The study provides theoretical support for understanding rock fracture mechanisms, offers guidance for the selection and proportioning of similar materials, and holds significance for predicting and controlling rock fracture behavior in engineering applications.

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Microscopic Investigation of Rock Direct Tensile Failure Based on Statistical Analysis of Acoustic Emission Waveforms

Cited by 20 publications

References 23 publications

Bending-damaged fracture criterion and numerical implementation of limestone beam under three-point bending test

Bending-damaged fracture criterion and numerical implementation of limestone beam under three-point bending test

Early Detection of Coal Spontaneous Combustion by Complex Acoustic Waves in a Concealed Fire Source

Acoustic emission characteristic of sandstone and sandstone like material under multi-path loading

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