scholarly journals Эмиссионная активность при ударном разрушении керамик A-=SUB=-2-=/SUB=-B-=SUB=-6-=/SUB=-

2018 ◽  
Vol 44 (15) ◽  
pp. 58
Author(s):  
И.П Щербаков ◽  
А.A. Дунаев ◽  
А.Е. Чмель
Keyword(s):  
Time Series ◽  
Acoustic Emission ◽  
Crystallite Size ◽  
Time Resolution ◽  
Impact Loading ◽  
Electromagnetic Emission ◽  
Mechanical Action ◽  
Parallel Time ◽  
Emission Activity

AbstractIn this paper, we present results of a study of the generation of electromagnetic emission during impact loading of ZnS and ZnSe ceramics prepared by various techniques. The choice of the type of mechanical action is associated with the typical applications of these ceramics. Separate contributions to emission activity from the dislocations movement and the microcracks development depending on the crystallite size in the ceramics are shown. The electromagnetic emission is compared with parallel time series of pulses of mechanoluminescence and acoustic emission. In all three cases, emission activity was recorded with a time resolution of 10 ns.

scholarly journals Акустическая и электромагнитная эмиссии при ударном повреждении сверхтвердых керамик SiC и AlMg-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=-

2019 ◽  
Vol 61 (10) ◽  
pp. 1763
Author(s):  
А.Г. Кадомцев ◽  
Е.В. Гольева ◽  
А.A. Дунаев ◽  
А.Е. Чмель ◽  
И.П. Щербаков
Keyword(s):  
Acoustic Emission ◽  
Impact Damage ◽  
Atmospheric Precipitation ◽  
Electromagnetic Emission ◽  
Optical Devices ◽  
Dust Particles ◽  
Wide Spectral Range ◽  
Impact Action ◽  
Emission Activity ◽  
Different Origin

AbstractIn this paper, we employ SiC super hard ceramics that are widely used for the manufacture of individual means of protecting people from point impact effects and MgAl_2O_4 ceramics transparent in a wide spectral range that are used for protective screens of optical devices of aircraft, which are exposed to solid dust particles and atmospheric precipitation. Here, we study generation and relaxation of microcracks under impact action by using acoustic emission and electromagnetic emission, respectively. Since the mechanism of generation of these types of emissions has a different origin, then a comparison of the emission activity of one and another type allowed identifying general and individual patterns of impact damage to SiC and MgAl_2O_4 solid ceramics.

Estimation of Rock In-Situ Stress by Acoustic and Electromagnetic Emission

2006 ◽  
Vol 13-14 ◽  
pp. 357-362 ◽  
Author(s):  
Yasuhiko Mori ◽  
P. Sedlak ◽  
Josef Sikula
Keyword(s):  
Acoustic Emission ◽  
Simultaneous Measurement ◽  
Rock Sample ◽  
Electromagnetic Emission ◽  
In Situ Stress ◽  
New Method ◽  
Acoustic Emission Activity ◽  
Kaiser Effect ◽  
Emission Activity

The Kaiser Effect in acoustic emission is often used for an estimation of the stress to which rocks have been subjected. However, there are cases in which the Kaiser Effect is not clear, since the noises due to the contact and/or the stick slip between the pre-induced fracture surfaces are measured during the reloading process. In such cases, estimation of previous stress is difficult by the conventional method which is based on the acoustic emission activity observed under reloading process. In the tests for the Kaiser Effect on rocks, therefore, the noises must be eliminated from the acoustic emission generated from newly created cracks during the second loading process. Such techniques as analysis of the difference between the acoustic emission activity observed in the first and second reloading and the analysis of the change in the slope of the acoustic emission amplitude distribution have been proposed. In this paper we present a new method by which the maximum previous stress in rocks can be directly estimated without any post signal analysis. In the new method, simultaneous measurement of acoustic and electromagnetic emission during loading test of rock sample is employed. The electromagnetic emission in the deformation of rock sample generates only when the fresh surfaces due to cracking are created in the material, and the source of electromagnetic emission is the electrification between the fresh crack surfaces. This paper describes the simultaneous measurement of acoustic and electromagnetic emission useful for estimating the rock in-situ stress.

Tool Wear Detection Using Time Series Analysis of Acoustic Emission

1989 ◽  
Vol 111 (3) ◽  
pp. 199-205 ◽  
Author(s):  
S. Y. Liang ◽  
D. A. Dornfeld
Keyword(s):  
Time Series ◽  
Acoustic Emission ◽  
Tool Wear ◽  
Time Series Analysis ◽  
Cutting Tool ◽  
Shear Zones ◽  
Parameter Vector ◽  
Model Parameter ◽  
Cutting Tool Wear ◽  
Series Analysis

This paper discusses the monitoring of cutting tool wear based on time series analysis of acoustic emission signals. In cutting operations, acoustic emission provides useful information concerning the tool wear condition because of the fundamental differences between its source mechanisms in the rubbing friction on the wear land and the dislocation action in the shear zones. In this study, a signal processing scheme is developed which uses an autoregressive time-series to model the acoustic emission generated during cutting. The modeling scheme is implemented with a stochastic gradient algorithm to update the model parameters adoptively and is thus a suitable candidate for in-process sensing applications. This technique encodes the acoustic emission signal features into a time varying model parameter vector. Experiments indicate that the parameter vector ignores the change of cutting parameters, but shows a strong sensitivity to the progress of cutting tool wear. This result suggests that tool wear detection can be achieved by monitoring the evolution of the model parameter vector during machining processes.

Control of Defects on the Parameters of the Electromagnetic Response under Pulsed Mechanical Excitation of the Sample

2015 ◽  
Vol 1085 ◽  
pp. 316-318
Author(s):  
Petr Khorsov ◽  
Nikolay Khorsov ◽  
Vladimir Surzhikov
Keyword(s):  
Acoustic Emission ◽  
Dielectric Material ◽  
Electromagnetic Emission ◽  
Excitation Pulse ◽  
Electromagnetic Response ◽  
Electromagnetic Signal ◽  
Random Component ◽  
Dielectric Sample ◽  
Random Components ◽  
Stepwise Loading

The paper assessed the possibility of using acoustic emission from the dielectric sample during stepwise loading. The electromagnetic signal from the sample was detected by using an apparatus of mechanical repeatedly pulsed excitation of the sample at each stage of loading. It was found that the response consists of a deterministic component (due to the excitation pulse) and random components noise and acoustic emission. It were allocated random components, calculated their standard deviations. The influence of the electromagnetic emission on standard deviation of the random component of response under step load on the specimen was evaluated. It has been shown that the component of the electromagnetic emission can be an informative parameter to evaluate defectiveness of the object of a dielectric material under load.

scholarly journals Local stress fields in solids estimated by acoustical emission method

2021 ◽  
Vol 2103 (1) ◽  
pp. 012064
Author(s):  
V L Hilarov ◽  
E E Damaskinskaya
Keyword(s):  
Time Series ◽  
Acoustic Emission ◽  
Stress Field ◽  
Estimation Method ◽  
Local Stress ◽  
Stress Fields ◽  
Emission Method ◽  
Macroscopic Fracture ◽  
Stress Estimation ◽  
Kinetic Concept

Abstract Based on the Zhurkov’s kinetic concept of solids’ fracture a local internal stress estimation method is introduced. Stress field is computed from the time series of acoustic emission intervals between successive signals. For the case of two structurally different materials the time evolution of these stresses is examined. It is shown that temporal changes of these stresses’ accumulation law may serve as a precursor of incoming macroscopic fracture.

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.

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