Quantitative statistical analysis of the crack propagation and fracture process of self‐compacting rubber concrete based on acoustic emission

2021 ◽  
Author(s):  
Pan Ming ◽  
Jun Lu ◽  
Miaoyan Liu ◽  
Xin Cai ◽  
Xudong Chen
Keyword(s):  
Acoustic Emission ◽  
Statistical Analysis ◽  
Crack Propagation ◽  
Fracture Process ◽  
Rubber Concrete

Study on Acoustic Emission Signatures during the Process of Edge Chipping for Engineering Ceramics

2011 ◽  
Vol 697-698 ◽  
pp. 93-96 ◽  
Author(s):  
Xiu Jian Tang ◽  
Xin Li Tian ◽  
Jian Quan Wang ◽  
Ya Tao Mao ◽  
F.Q. Li
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Static Load ◽  
Average Frequency ◽  
Displacement Curve ◽  
Edge Chipping ◽  
Kaiser Effect ◽  
Engineering Ceramics ◽  
Highly Active ◽  
Fracture Processes

The developments of edge chipping for engineering ceramics are analyzed. An edge chipping experiment under static load is adopted to study the fracture process of edge chipping. The results show that the fracture processes of edge chipping under different edge distances are similar, which can be divided into four stages based on load-displacement curve. There is obviously Kaiser Effect during the fracture processes of edge chipping. Counts, average frequency, RMS, duration, amplitude and inverse calculation can be used to describe the process of edge chipping for engineering ceramics. Amplitude, duration and average frequency become highly active on the eve of fracture, which can be regard as the omens of edge chipping and used to predict the fracture of edge chipping.

Study of the Metal Crack Propagation by Acoustic Emission Testing

2011 ◽  
Vol 105-107 ◽  
pp. 2179-2182
Author(s):  
Wei Min Zhang ◽  
Shu Xuan Liu ◽  
Yong Qiu ◽  
Cheng Feng Chen
Keyword(s):  
Acoustic Emission ◽  
Crack Propagation ◽  
Acquisition System ◽  
Signal Acquisition ◽  
Sensor Signal ◽  
Acoustic Emission Sensor ◽  
Axial Tension ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Signal Operating

Crack propagation is the main reason which leads to the invalidity of the metal components. A set of detecting equipment based on the acoustic emission method was designed, and it was mainly composed of acoustic emission sensor, signal operating circuits and signal acquisition system. Specimens of 16MnR material were manufactured and the static axial tension test of them was carried on. Acoustic emission signals from the specimen were detected by acoustic emission equipment by using piezoelectric ceramic sensor. Signal datum were acquired and operated by the acquisition system, as well as the acquisition program written for it. The final results has demonstrated that acoustic emission equipment designed for the test performed well in acquiring the signals induced by the metal crack propagation.

Experimental analysis of crack evolution in concrete by the acoustic emission technique

2015 ◽  
Author(s):  
J. Saliba ◽  
A. Loukili ◽  
J.P. Regoin ◽  
D. Grégoire ◽  
L. Verdon ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Process ◽  
Process Zone ◽  
Mouth Opening ◽  
Acoustic Emissions ◽  
Plain Concrete ◽  
Crack Mouth Opening Displacement ◽  
Notch Depth ◽  
Opening Displacement ◽  
Magnitude Distribution

The fracture process zone (FPZ) was investigated on unnotched and notched beams with different notch depths. Three point bending tests were realized on plain concrete under crack mouth opening displacement (CMOD) control. Crack growth was monitored by applying the acoustic emission (AE) technique. In order to improve our understanding of the FPZ, the width and length of the FPZ were followed based on the AE source locations maps and several AE parameters were studied during the entire loading process. The bvalue analysis, defined as the log-linear slope of the frequency-magnitude distribution of acoustic emissions, was also carried out to describe quantitatively the influence of the relative notch depth on the fracture process. The results show that the number of AE hits increased with the decrease of the relative notch depth and an important AE energy dissipation was observed at the crack initiation in unnotched beams. In addition, the relative notch depth influenced the AE characteristics, the process of crack propagation, and the brittleness of concrete.

scholarly journals Progressive Failure and Acoustic Emission Characteristics of Red Sandstone with Different Geometry Parallel Cracks under Uniaxial Compression Loading

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Xizhen Sun ◽  
Fanbao Meng ◽  
Ce Zhang ◽  
Xucai Zhan ◽  
He Jiang
Keyword(s):  
Acoustic Emission ◽  
Crack Initiation ◽  
Crack Propagation ◽  
Geometric Distribution ◽  
Progressive Failure ◽  
Fractured Rock ◽  
Propagation Mode ◽  
Wing Crack ◽  
Red Sandstone ◽  
Parallel Cracks

The geometric distribution of initial damages has a great influence on the strength and progressive failure characteristics of the fractured rock mass. Initial damages of the fractured rock were simplified as parallel cracks in different geometric distributions, and then, the progressive failure and acoustic emission (AE) characteristics of specimens under the uniaxial compression loading were analyzed. The red sandstone (brittle materials) specimens with the parallel preexisting cracks by water jet were used in the tests. The energy peak and stress attenuation induced by the energy release of crack initiation were intuitively observed in the test process. Besides, three modes of rock bridge coalescence were obtained, and wing crack was the main crack propagation mode. The wing crack and other cracks were initiated in different loading stages, which were closely related to the energy level of crack initiation. The propagation of wing crack (stable crack) consumed a large amount of energy, and then, the propagation of shear crack, secondary crack, and anti-wing crack (unstable crack) was inhibited. The relationship between the crack propagation mode and the geometric distribution of existing cracks in the specimen was revealed. Meanwhile, the strength characteristic and failure mode of fractured rock with the different geometric distributions of preexisting crack were also investigated. The energy evolution characteristics and crack propagation were also analyzed by numerical modeling (PFC2D).

Study on Interfacial Crack Propagation and Fracture between Embedded Steel and HSHPC

2007 ◽  
Vol 348-349 ◽  
pp. 853-856
Author(s):  
Shan Suo Zheng ◽  
Lei Li ◽  
Guo Zhuan Deng ◽  
Liang Zhang
Keyword(s):  
Crack Propagation ◽  
High Performance ◽  
Fracture Process ◽  
Fracture Process Zone ◽  
High Performance Concrete ◽  
Process Zone ◽  
Interfacial Crack ◽  
High Strength ◽  
Interfacial Fracture ◽  
Softening Process

Steel reinforced high strength and high performance concrete (SRHSHPC) specimens were experimented to study the mechanical behaviors between steel and concrete interface. In experiment, interfacial bond softening process was observed, which can be explained in terms of damage along the interface, leading to progressive reduction of shear transfer capability between steel and high strength and high performance concrete (HSHPC). In this paper, bond softening process along the interface is considered in the analysis of crack-induced debonding. Interfacial bond-slip mechanism between steel and HSHPC is studied in detail based on fracture mechanics. With the help of acoustic emissions technology, the crack propagation in the interlayer was observed, thus the interfacial crack propagation and fracture model is set up. Under the assumption that the interlayer is weak concrete compared with concrete matrix, the stress field as well as displacement field around the crack tip is deduced. The characteristics of interfacial fracture process are discussed and a model for interfacial fracture process zone is built up. With this model, the size of fracture process zone can be derived. At last, the influence of the fracture process zone on interfacial fracture toughness is determined using critical fracture toughness. All these may contribute to improvement of theory for SRHSHPC composite structure.

LONG RANGE CORRELATION PROPERTIES OF AFTERSHOCK RELAXATION SIGNALS

Fractals ◽  
1995 ◽  
Vol 03 (04) ◽  
pp. 839-847 ◽  
Author(s):  
A. VESPIGNANI ◽  
A. PETRI ◽  
A. ALIPPI ◽  
G. PAPARO ◽  
M. COSTANTINI
Keyword(s):  
Time Series ◽  
Acoustic Emission ◽  
Statistical Analysis ◽  
Power Spectrum ◽  
Power Law ◽  
Amplitude Distribution ◽  
Relaxation Processes ◽  
Critical Dynamics ◽  
Range Correlation ◽  
Correlation Properties

Relaxation processes taking place after microfracturing of laboratory samples give rise to ultrasonic acoustic emission signals. Statistical analysis of the resulting time series has revealed many features which are characteristic of critical phenomena. In particular, the autocorrelation functions obey a power-law behavior, implying a power spectrum of the kind 1/f. Also the amplitude distribution N(V) of such signals follows a power law, and the obtained exponents are consistent with those found in other experiments: N(V) dV≃V–γ dV, with γ=1.7±0.2. We also analyzed the distribution N(τ) of the delay time τ between two consecutive acoustic emission events. We found that a N(τ) distribution rather close to a power law constitutes a common feature of all the recorded signals. These experimental results can be considered as a striking evidence for a critical dynamics underlying the microfracturing processes.

Research on fatigue crack propagation of micro-alloyed steel by acoustic emission

2015 ◽  
Vol 19 (sup5) ◽  
pp. S5-420-S5-422 ◽  
Author(s):  
H. W. Wang ◽  
H. Q. Xiao ◽  
H. Bai ◽  
H. Bai ◽  
Z. Y. Han ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Alloyed Steel ◽  
Micro Alloyed Steel
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