In-situ damage assessment of FML joints under uniaxial tension combining with acoustic emission and DIC: Geometric influence on damage formation

To explore the mechanical properties and damage evolution characteristics of carbonaceous shale with different confining pressures and water-bearing conditions, triaxial compression tests accompanied by simultaneous acoustic emission (AE) monitoring were conducted on carbonaceous shale rock specimens. The AE characteristics of carbonaceous shale were investigated, a damage assessment method based on Shannon entropy of AE was further proposed. The results suggest that the mechanical properties of carbonaceous shale intensify with increasing confining pressure and degrade with increasing water content. Moisture in rocks does not only weaken the cohesion but also reduce the internal friction angle of carbonaceous shale. It is observed that AE activities mainly occur in the post-peak stage and the strong AE activities of saturated carbonaceous shale specimens appear at a lower normalized stress level than that of natural-state specimens. The maximum AE counts and AE energy increase with water content while decrease with confining pressure. Both confining pressure and water content induce changes in the proportions of AE dominant frequency bands, but the changes caused by confining pressure are more significant than those caused by water content. The results also indicate that AE entropy can serve as an applicable index for rock damage assessment. The damage evolution process of carbonaceous shale can be divided into two main stages, including the stable damage development stage and the damage acceleration stage. The damage variable increases slowly accompanied by a few AE activities at the first stage, which is followed by a rapid growth along with intense acoustic emission activities at the damage acceleration stage. Moreover, there is a sharp rise in the damage evolution curve for the natural-state specimen at the damage acceleration stage, while the damage variable develops slowly for the saturated-state specimen.

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Crack monitoring and damage assessment of BFRP-jacketed concrete cylinders under compression load based on acoustic emission techniques

Construction and Building Materials ◽

10.1016/j.conbuildmat.2020.121936 ◽

2021 ◽

Vol 272 ◽

pp. 121936

Author(s):

Gao Ma ◽

Cheng Wu ◽

Hyeon-Jong Hwang ◽

Bo Li

Keyword(s):

Acoustic Emission ◽

Damage Assessment ◽

Compression Load ◽

Concrete Cylinders ◽

Crack Monitoring

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Analysis of acoustic emission entropy for damage assessment of pearlitic ductile cast irons

Material Design & Processing Communications ◽

10.1002/mdp2.158 ◽

2020 ◽

Vol 2 (3) ◽

Cited By ~ 1

Author(s):

Danilo D'Angela ◽

Marianna Ercolino ◽

Costanzo Bellini ◽

Vittorio Di Cocco ◽

Francesco Iacoviello

Keyword(s):

Acoustic Emission ◽

Damage Assessment ◽

Cast Irons

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Uniaxial tension damage mechanics of steel fiber reinforced concrete using acoustic emission and machine learning crack mode classification

Cement and Concrete Composites ◽

10.1016/j.cemconcomp.2021.104205 ◽

2021 ◽

pp. 104205

Author(s):

J.G. Yue ◽

Y.N. Wang ◽

D.E. Beskos

Keyword(s):

Machine Learning ◽

Acoustic Emission ◽

Reinforced Concrete ◽

Uniaxial Tension ◽

Damage Mechanics ◽

Steel Fiber ◽

Fiber Reinforced Concrete ◽

Fiber Reinforced ◽

Steel Fiber Reinforced Concrete

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In situ characterization of the functional degradation of a [001¯] oriented Fe-Mn-Al-Ni single crystal under compression using acoustic emission measurements

Acta Materialia ◽

10.1016/j.actamat.2021.117333 ◽

2021 ◽

pp. 117333

Author(s):

Anja Weidner ◽

Alexei Vinogradov ◽

Malte Vollmer ◽

Phillip Krooß ◽

Mario J. Kriegel ◽

...

Keyword(s):

Acoustic Emission ◽

Single Crystal ◽

In Situ Characterization

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A Simple and Accurate Interpretation Method of In Situ Stress Measurement Based on Rock Kaiser Effect and Its Application

Geofluids ◽

10.1155/2018/9463439 ◽

2018 ◽

Vol 2018 ◽

pp. 1-13 ◽

Cited By ~ 2

Author(s):

Kang Zhao ◽

Shuijie Gu ◽

Yajing Yan ◽

Keping Zhou ◽

Qiang Li ◽

...

Keyword(s):

Acoustic Emission ◽

Fractal Dimension ◽

Principal Stress ◽

In Situ Stress ◽

Time Range ◽

Kaiser Effect ◽

Time Stress ◽

Stress Curve ◽

Interpretation Method

Many deep underground excavation practices show that the size and distribution of in situ stress are the main factors resulting in the deformation and instability of the surrounding rock structure. The in situ stress measured by the Kaiser effect of rock is used by engineers because of its economy and convenience. However, due to the lack of quantitative judgment basis in determining the Kaiser point position, there is a large artificial error in the practical application. In response to the problem, this study systematically investigates the characteristics of rock acoustic emission curve on the basis of the fractal theory and establishes an accurate and simple interpretation method for determining the Kaiser point position. The indoor rock acoustic emission test was carried out by drilling a rock sample at a mine site. By using the conventional tangent method, the cumulative ringing count rate-time-stress curve of rock acoustic emission is analyzed to preliminarily determine the time range of Kaiser point appearance. Considering that the fractal dimension of the rock Kaiser point is lower than the adjacent point, the minimum point of the fractal dimension of this time range can be determined from the fractal dimension-time-stress curve. Such determined point is the Kaiser point. The size of the in situ stress is calculated using an analytical method. Based on the value of the in situ stress, the distribution of the in situ stress in the mining area is further analyzed using the geological structure of the mine. The maximum principal stress is 19.38 MPa, with a direction of N (30°-40°) E, and the minimum principal stress is 8.02 MPa with a direction of N (50°-60°) W. The maximum and minimum principal stresses are approximately in the horizontal plane. The intermediate principal stress is 11.73 MPa in vertically downward. These results are basically consistent with the distribution statistical law of the measured in situ stress fields in the world. The results presented in the study could provide a reference for the later mining, stability evaluation, and support of the surrounding rock.

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