Acoustic Emission Source Location and Experimental Verification for Two-Dimensional Irregular Complex Structure

Hu, Qingchun; Dong, Longjun

doi:10.1109/jsen.2019.2954200

Cited by 43 publications

(9 citation statements)

References 30 publications

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“…Acoustic emission (AE) analysis provide spatial-temporal information about the evolution process of rock fracture [3][4][5][6], where the AE waveforms emitted under different fracture modes have obvious differences [7]. Combining the time domain and frequency domain characteristics of AE signals is a significant means to characterize rock fracture types.…”

Section: Introductionmentioning

confidence: 99%

Micro-Crack Mechanism in the Fracture Evolution of Saturated Granite and Enlightenment to the Precursors of Instability

Dong

Zhang

2020

Sensors

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To explore the potential precursors of rock instability, it is necessary to clarify the mechanism of micro-crack from fracturing to failure, which involves the evolution of fracture size, orientation, source model, and their relationships to the loading. The waveforms of acoustic emission (AE) recorded by the sensor network attached rock sample during laboratory tests provide a data basis for solving these problems, since these observations are directly related to the characteristics of the fracturing sources. Firstly, we investigated the source mechanism, looking at the rise angle and the average frequency (RA-AF) trends during five loading stages in a uniaxial compression test. Results show that the proportion of shear events significantly increases when approaching instability. Secondly, we calculated the moment tensor for each event, considering the uncertainties of P-wave polarity, azimuth, and the takeoff angles of the rays. Moment tensor solutions suggest that there are obviously more crack events than shear events in all loading stages. Moment tensor evolutions confirmed that the decreasing of isotropic component and the increment of double-couple can be used as precursors of rock fracturing development. Considering the limitations of these two methods, it is suggested that we should be concerned more about the proportions of individual failure components and their evolutions over time, instead of absolutely classifying the events into a certain source type.

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Section: Introductionmentioning

confidence: 99%

Micro-Crack Mechanism in the Fracture Evolution of Saturated Granite and Enlightenment to the Precursors of Instability

Dong

Zhang

2020

Sensors

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“…The researches show that the AE localization results basically correspond to the actual damage. At the same time, the AE source localization method overcomes factors such as the pre-determined wave velocity (Dong et al, 2011) and the wave's propagation path (Hu and Dong, 2019) as a straight line in the update iteration to achieve high-precision positioning for complex spatial structures (Dong et al, 2020a,b). In order to meet the stress environment in which deep rock masses are located, carrying out laboratory AE experiments under complex stress paths (Du et al, 2016) provides a more effective ground reference value for engineering practice.…”

Section: Introductionmentioning

confidence: 99%

AE Characteristics of Rockburst Tendency for Granite Influenced by Water Under Uniaxial Loading

Zhang

Sun

et al. 2020

Front. Earth Sci.

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In deep mining, granite is stored with high energy duing to its structural integrity and brittleness. Rock bursts usually occur because stress changes and mining disturbances during mining, which seriously threaten safe production. Focusing on the factor -waterwhich may reduce the brittleness and rockburst tendency of granite, this work discussed the brittleness index and AE characteristics of dry and saturated water granite samples under uniaxial loading. The results show that the peak strength and elastic modulus of the saturated water granite are reduced. The damage degree of the water sample is larger than that of the dry sample, and the brittle failure is significantly reduced. The cumulative number of acoustic emission (AE) events in saturated water granite is significantly reduced compared to the dry sample, which is a decrease of 31.5%. However, AE event rate is higher than that of dry granite in the late loading period; AE quiet period of saturated water granite lasts longer and is more obvious than that of dry granite. Dry granite stores and releases more energy during the whole loading process, and the proportion of high energy level AE events in the later stage of loading is higher. The b value of the two samples show a downward trend with fluctuation in the critical state of fracture and a jump increases at the moment of instability. The decrease of b values of dry granite is larger than that of saturated water granite. Results suggest that the decline of AE b value of granite can be taken as the precursor of rock burst, and water can significantly reduce the rockburst tendency of granite.

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“…Dong et al [14] combine with the arrivals of multi-sensor and inversion of the real-time average for iterative method based on the time differences to locate source coordinates with clear arrivals. SSL monitors the development of the crack in real time for the complex structure by searching the fastest wave path over the structure with irregular spaces in order to improve location accuracy [15]. An analytical SSL method was developed for a simplified algorithm and conditions without an iterative algorithm, without pre-measured velocity, without initial value, and without square root operations [16].…”

Section: Introductionmentioning

confidence: 99%

Parametric Estimations Based on Homomorphic Deconvolution for Time of Flight in Sound Source Localization System

Park

Choi

Kim

2020

Sensors

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Vehicle-mounted sound source localization systems provide comprehensive information to improve driving conditions by monitoring the surroundings. The three-dimensional structure of vehicles hinders the omnidirectional sound localization system because of the long and uneven propagation. In the received signal, the flight times between microphones delivers the essential information to locate the sound source. This paper proposes a novel method to design a sound localization system based on the single analog microphone network. This article involves the flight time estimation for two microphones with non-parametric homomorphic deconvolution. The parametric methods are also suggested with Yule-walker, Prony, and Steiglitz-McBride algorithm to derive the coefficient values of the propagation model for flight time estimation. The non-parametric and Steiglitz-McBride method demonstrated significantly low bias and variance for 20 or higher ensemble average length. The Yule-walker and Prony algorithms showed gradually improved statistical performance for increased ensemble average length. Hence, the non-parametric and parametric homomorphic deconvolution well represent the flight time information. The derived non-parametric and parametric output with distinct length will serve as the featured information for a complete localization system based on machine learning or deep learning in future works.Sensors 2020, 20, 925 2 of 32 deliver the situation over the non-line-of-sight (NLOS) locations. Presently, the human and vehicle are cooperated to drive the transport sorely based on the vision information. Hence, indirect imminent endangerment cannot be realized until the human has the visual contact. For example, a car with emergency braking cannot be perceived by the indirect position observers. The squeal sound provides the situation. However, the system cannot recognize the direction to activate the pre-emptive safety devices which reduce or remove the impact of the secondary collisions. The sound information can be used for improving the safety of future autonomous transport system.The driver barely obtains the acoustic information since the vehicle structure debilitates the propagation by airtight cabin. The acoustic perception on sound source and arrival direction are both required to understand the situation. The SSL system mounted on a vehicle could provide the comprehensive information to improve the driving conditions by monitoring the surroundings including the NLOS observation. The conventional SSL approaches recently employed for transport are as follows. The moving vehicle presences are identified by sound localization based on the arrival time difference between the microphones [8]. A sensing technique to localize an approaching vehicle is proposed by an acoustic cue from the spatial-temporal gradient method [9]. For the sequential movement events of vehicles, robust direction-of-arrival estimation is realized by the incoherent signal-subspace method based on a small microphone array [10].The 3D structure of ve...

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Acoustic Emission Source Location and Experimental Verification for Two-Dimensional Irregular Complex Structure

Cited by 43 publications

References 30 publications

Micro-Crack Mechanism in the Fracture Evolution of Saturated Granite and Enlightenment to the Precursors of Instability

Micro-Crack Mechanism in the Fracture Evolution of Saturated Granite and Enlightenment to the Precursors of Instability

AE Characteristics of Rockburst Tendency for Granite Influenced by Water Under Uniaxial Loading

Parametric Estimations Based on Homomorphic Deconvolution for Time of Flight in Sound Source Localization System

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