scholarly journals A New Algebraic Solution for Acoustic Emission Source Localization without Premeasuring Wave Velocity

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 459
Author(s):  
Zilong Zhou ◽  
Riyan Lan ◽  
Yichao Rui ◽  
Longjun Dong ◽  
Xin Cai
Keyword(s):  
Acoustic Emission ◽  
Wave Velocity ◽  
Source Localization ◽  
Algebraic Solution ◽  
Positioning Accuracy ◽  
Complex Engineering ◽  
Velocity Changes ◽  
Engineering Practices ◽  
Intermediate Variables ◽  
Squared Residuals

The technique of acoustic emission (AE) source localization is critical for studying material failure mechanism and predicting the position of potential hazards. Most existing positioning methods heavily depend on the premeasured wave velocity and are not suitable for complex engineering practices where the wave velocity changes dynamically. To reduce the influence of measurement error of wave velocity on location accuracy, this paper proposes a new algebraic solution for AE source localization without premeasuring wave velocity. In this method, the nonlinear TDOA equations are established and linearized by introducing two intermediate variables. Then, by minimizing the sum of squared residuals of the linear TDOA equations with respect to the AE source coordinate and two intermediate variables separately, the optimal algebraic solution of the AE source coordinate in the least squares sense is obtained. A pencil-lead breaks experiment is performed to validate the positioning effectiveness of the proposed method. The results show that the new method improves the positioning accuracy by more than 40% compared with two pre-existing methods, and the minimum positioning accuracy of the proposed method can reach 1.12 mm. Moreover, simulation tests are conducted to further verify the location performance of the proposed method under different TDOA errors and the number of sensors.

scholarly journals Study on Acoustic Emission Localization of Concrete Using Modified Velocity

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Jiapeng Li ◽  
Lei Qin
Keyword(s):  
Acoustic Emission ◽  
Wave Velocity ◽  
Source Localization ◽  
Wave Speed ◽  
Localization Algorithm ◽  
Measured Velocity ◽  
3D Localization ◽  
Before And After ◽  
Ae Signal ◽  
Ae Location

To improve the accuracy of the acoustic emission (AE) source localization, a new 3D AE source localization method was investigated which used a combination of the modified velocity and the 3D localization algorithm based on the exhaustive method. The wave speed has a significant effect on the AE location results. With the increase of distance, the AE signal seriously attenuated due to the anisotropy of concrete, and the measured velocity changed for various distances. The velocity-distance curves were obtained when employing different water-cement ratios (W/C) and aggregate sizes. However, the current AE location system adopted constant wave velocity. As a result, the error was tremendous. The accuracy of the localization before and after the modified velocity was compared. The 3D localization results showed that compared with the constant wave velocity, the position deviation of the modified velocity was smaller and the localization results with the modified velocity were more accurate.

Acoustic Emission Source Localization in Ring Gears from Wind Turbine Planetary Gearboxes

2019 ◽  
Vol 83 (1) ◽  
pp. 43-52 ◽  
Author(s):  
Felix Leaman ◽  
Steffen Hinderer ◽  
Ralph Baltes ◽  
Elisabeth Clausen ◽  
Brian Rieckhoff ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Wind Turbine ◽  
Source Localization ◽  
Emission Source ◽  
Acoustic Emission Source

Near-field beamforming analysis for acoustic emission source localization

Ultrasonics ◽  
2012 ◽  
Vol 52 (5) ◽  
pp. 587-592 ◽  
Author(s):  
Tian He ◽  
Qiang Pan ◽  
Yaoguang Liu ◽  
Xiandong Liu ◽  
Dayong Hu
Keyword(s):  
Acoustic Emission ◽  
Source Localization ◽  
Near Field ◽  
Emission Source ◽  
Acoustic Emission Source

scholarly journals The effect of liquid nitrogen cooling on coal cracking and mechanical properties

2018 ◽  
Vol 36 (6) ◽  
pp. 1609-1628 ◽  
Author(s):  
Chengzheng Cai ◽  
Feng Gao ◽  
Yugui Yang
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Acoustic Emission ◽  
Liquid Nitrogen ◽  
Wave Velocity ◽  
Count Rate ◽  
Initial State ◽  
Nitrogen Injection ◽  
Strength Tests ◽  
Liquid Nitrogen Cooling

Liquid nitrogen is a type of super-cryogenic fluid, which can cause the reservoir temperature to decrease significantly and thereby induce formation rock damage and cracking when it is injected into the wellbore as fracturing fluid. An experimental set-up was designed to monitor the acoustic emission signals of coal during its contact with cryogenic liquid nitrogen. Ultrasonic and tensile strength tests were then performed to investigate the effect of liquid nitrogen cooling on coal cracking and the changes in mechanical properties thereof. The results showed that acoustic emission phenomena occurred immediately as the coal sample came into contact with liquid nitrogen. This indicated that evident damage and cracking were induced by liquid nitrogen cooling. During liquid nitrogen injection, the ring-down count rate was high, and the cumulative ring-down counts also increased rapidly. Both the ring-down count rate and the cumulative ring-down counts during liquid nitrogen injection were much greater than those in the post-injection period. Liquid nitrogen cooling caused the micro-fissures inside the coal to expand, leading to a decrease in wave velocity and the deterioration in mechanical strength. The wave velocity, which was measured as soon as the sample was removed from the liquid nitrogen (i.e. the wave velocity was recorded in the cooling state), decreased by 14.46% on average. As the cryogenic samples recovered to room temperature, this value increased to 18.69%. In tensile strength tests, the tensile strengths of samples in cooling and cool-treated states were (on average) 17.39 and 31.43% less than those in initial state. These indicated that both during the cooling and heating processes, damage and cracking were generated within these coal samples, resulting in the acoustic emission phenomenon as well as the decrease in wave velocity and tensile strength.

scholarly journals Modelling time-lapse shear-wave velocity changes in an unsaturated soil embankment due to water infiltration and drainage

First Break ◽  
2017 ◽  
Vol 35 (8) ◽  
Author(s):  
Atsushi Suzaki ◽  
Shohei Minato ◽  
Ranajit Ghose ◽  
Chisato Konishi ◽  
Naoki Sakai
Keyword(s):  
Shear Wave ◽  
Wave Velocity ◽  
Shear Wave Velocity ◽  
Unsaturated Soil ◽  
Time Lapse ◽  
Water Infiltration ◽  
Velocity Changes
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