Characterization of acoustic emission signals from fatigue fracture

2000 ◽  
Vol 214 (9) ◽  
pp. 1141-1149 ◽  
Author(s):  
Z Shi ◽  
J Jarzynski ◽  
S Bair ◽  
S Hurlebaus ◽  
L. J. Jacobs
Keyword(s):  
Acoustic Emission ◽  
Transfer Functions ◽  
Fatigue Cracks ◽  
Experimental Program ◽  
Fracture Mechanisms ◽  
Torsional Fatigue ◽  
Quantitative Understanding ◽  
Critical Components ◽  
Ae Signals ◽  
Geometric Effects

This paper discusses a comprehensive study that is developing a quantitative understanding of the acoustic emission (AE) signals that emanate from fatigue cracks. Two critical components of this study are the development of a transfer function that quantifies and removes geometric effects from a measured AE waveform and an experimental program that monitors and identifies AE signals that occur during the fatigue of cylindrical stainless steel specimens under torsion. Typical waveforms are collected during torsional fatigue and correlated with fracture mechanisms from different stages of testing. Three stages of fatigue are identified by AE waveform characterization and confirmed by microscopic replica observation. The other portion of this study demonstrates the effectiveness of using laser ultrasonic techniques to develop transfer functions to quantify and remove geometric effects from measured acoustic emission waveforms.

scholarly journals Damage Evolution and Fracture Events Sequence Analysis of Core-Shell Nanoparticle Modified Bone Cements by Acoustic Emission Technique

Polymers ◽  
2020 ◽  
Vol 12 (1) ◽  
pp. 208
Author(s):  
O.F. Pacheco-Salazar ◽  
Shuichi Wakayama ◽  
L.A. Can-Herrera ◽  
M.A.A. Dzul-Cervantes ◽  
C.R. Ríos-Soberanis ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Bone Cement ◽  
Solid Phase ◽  
Bending Test ◽  
Fracture Mechanisms ◽  
Core Shell ◽  
Bone Cements ◽  
Four Point Bending ◽  
Ae Signals ◽  
Cement Formulation

In this research, damage in bone cements that were prepared with core-shell nanoparticles was monitored during four-point bending tests through an analysis of acoustic emission (AE) signals. The core-shell structure consisted of poly(butyl acrylate) (PBA) as rubbery core and methyl methacrylate/styrene copolymer (P(MMA-co-St)) as a glassy shell. Furthermore, different core-shell ratios 20/80, 30/70, 40/60, and 50/50 were prepared and incorporated into the solid phase of the bone cement formulation at 5, 10, and 15 wt %, respectively. The incorporation of a rubbery phase into the bone cement formulation decreased the bending strength and bending modulus. The AE technique revealed that the nanoparticles play an important role on the fracture mechanism of the bone cement, since a higher amount of AE signals (higher amplitude and energy) were obtained from bone cements that were prepared with the nanoparticles in comparison with those without nanoparticles (the reference bone cement). The SEM examination of the fracture surfaces revealed that all of the bone cement formulations exhibited stress whitening, which arises from the development of crazes before the crack propagation. Finally, the use of the AE technique and the fracture surface analysis by SEM enabled insight into the fracture mechanisms that are presented during four-point bending test of the bone cement containing nanoparticles.

scholarly journals Acoustic emission for monitoring aircraft structures

2009 ◽  
Vol 223 (5) ◽  
pp. 525-532 ◽  
Author(s):  
K M Holford ◽  
R Pullin ◽  
S L Evans ◽  
M J Eaton ◽  
J Hensman ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Magnetic Particle ◽  
Fatigue Cracks ◽  
Principal Component ◽  
Fatigue Loading ◽  
Probability Density Functions ◽  
Aircraft Industry ◽  
Safety And Reliability ◽  
Critical Components

Structural health monitoring (SHM) is of paramount importance in the aircraft industry: not only to ensure the safety and reliability of aircraft in flight and to ensure timely maintenance of critical components, but also increasingly to monitor structures under test for airworthiness certification of new designs. This article highlights some of the recent advances in the acoustic emission (AE) technique as applied to SHM, and the new approaches that are crucial for the successful use of AE data for diagnostic purposes. These include modal analysis, enhanced location techniques, and novel signal processing approaches. A case study is presented on a landing gear component undergoing fatigue loading in which a linear location analysis using conventional techniques identified the position of fracture and final rupture of the specimen. A principal component analysis approach was used to separate noise signals from signals arising from fatigue cracks, which identified and located further fatigue crack positions, subsequently confirmed by magnetic particle inspection. Kernel probability density functions are used to aid visualization of the damage location.

scholarly journals Proportional monitoring of the acoustic emission in crypto-conditions

2011 ◽  
Vol 59 (5) ◽  
pp. 31-38 ◽  
Author(s):  
Petr Dostál ◽  
Michal Černý ◽  
Jaroslav Lev ◽  
David Varner
Keyword(s):  
Acoustic Emission ◽  
Aluminum Alloys ◽  
Real Time ◽  
Fatigue Cracks ◽  
Current Status ◽  
Fatigue Properties ◽  
Material Degradation ◽  
Emission Method ◽  
Important Benefit ◽  
Ae Signals

The work is aimed at studying corrosion and fatigue properties of aluminum alloys by means of acoustic emission (AE). During material degradation are acoustic events scanned and evaluated. The main objective of the article is a description of behavior of aluminum alloys degraded in specific conditions and critical degradation stages determination. The first part of the article describes controlled degradation of the material in the crypto–conditions. The acoustic emission method is used for process analyzing. This part contains the AE signals assessment and comparing aluminium alloy to steel. Then the specimens are loaded on high-cyclic loading apparatus for fatigue life monitoring. Also, the synergy of fatigue and corrosion processes is taken into account.The aim is the description of fatigue properties for aluminum alloys that have already been corrosion-degraded. Attention is also focused on the structure of fatigue cracks. The main part of the article is aimed at corrosion degradation of aluminium alloys researched in real time by means of AE. The most important benefit of AE detection/recording is that it provides information about the process in real time. Using this measurement system is possible to observe the current status of the machines/devices and to prevent serious accidents.

scholarly journals Application of New Techniques of Signal Processing for Detection of Wear Mechanisms in Turning of AISI 4340 Using Acoustic Emission

2021 ◽  
Author(s):  
Luis Henrique Andrade Maia ◽  
Alexandre Mendes Abrão ◽  
Wander Luiz Vasconcelos ◽  
Jánes Landre Júnior ◽  
Álisson Rocha Machado ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Wear Mechanisms ◽  
Tensile Tests ◽  
Machining Process ◽  
Fracture Mechanisms ◽  
Steel Turning ◽  
Short Time ◽  
Coated Carbide ◽  
Ae Signals ◽  
Aisi 4340

Abstract In this study, the short-time Fourier transform (STFT) technique was used to determine the wear mechanisms acting on uncoated and AlCrN-coated carbide tools and their variations during the machining process. To this end, tensile tests were performed on hardened AISI 4340 steel to characterize the acoustic emission (AE) signals and subsequently isolate the steel deformation and fracture mechanisms from the signs of tool wear during the steel turning. Machining tests were carried out using the following parameters: cutting speeds of 150, 200 and 250 m/min and feed rates of 0.10 and 0.20 mm/rev. The results demonstrate that AE signals in conjunction with STFT analysis can be used to identify abrasive wear, adhesive wear and other phenomena that occur during cutting.

Empirical Approach to Defect Detection Probability by Acoustic Emission Testing

2021 ◽  
Vol 11 (20) ◽  
pp. 9429
Author(s):  
Vera Barat ◽  
Artem Marchenkov ◽  
Valery Ivanov ◽  
Vladimir Bardakov ◽  
Sergey Elizarov ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Defect Detection ◽  
Probabilistic Models ◽  
Fatigue Cracks ◽  
A Priori ◽  
Empirical Approach ◽  
Empirical Generalization ◽  
Microstructure Parameters ◽  
A Priori Estimation ◽  
Ae Signals

Estimation of probability of defect detection (POD) is one of the most important problems in acoustic emission (AE) testing. It is caused by the influence of the material microstructure parameters on the diagnostic data, variability of noises, the ambiguous assessment of the materials emissivity, and other factors, which hamper modeling the AE data, as well as the a priori determination of the diagnostic parameters necessary for calculating POD. In this study, we propose an empirical approach based on the generalization of the experimental AE data acquired under mechanical testing of samples to a priori estimation of the AE signals emitted by the defect. We have studied the samples of common industrial steels 09G2S (similar to steel ANSI A 516-55) and 45 (similar to steel 1045) with fatigue cracks grown in laboratory conditions during cyclic testing. Empirical generalization of data using probabilistic models enables estimating the conditional probability of record emissivity and amplitudes of AE signals. This approach allows to eliminate the existing methodological gap and to build a comprehensive method for assessing the probability of fatigue cracks detection by the AE testing.

NON-DESTRUCTIVE EVALUATION AND STRENGTH CHARACTERISTICS OF CFRP WITH HEAT DAMAGE

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4285-4290 ◽  
Author(s):  
JIN WOOK KIM ◽  
YOUNG UN KIM ◽  
CHANG KWON MOON ◽  
SEOK HWAN AHN ◽  
KI WOO NAM
Keyword(s):  
Acoustic Emission ◽  
Structural Integrity ◽  
Matrix Cracking ◽  
Fracture Mechanisms ◽  
Heat Damage ◽  
Time Frequency ◽  
Reinforced Plastic ◽  
Damage Process ◽  
Distinct Frequency ◽  
Ae Signals

In this study, the heat-damage process of a carbon fiber reinforced plastic (CFRP) under monotonic tensile loading was characterized by acoustic emission. Additionally, epoxy specimens and prepreg specimens were used to determine the characteristics of acoustic emission (AE) signals of epoxy and fiber, respectively. The AE characteristics of CFRP showed three types of distinct frequency regions. Time-frequency analysis methods were employed for the analysis of fracture mechanisms in CFRP such as matrix cracking, debonding and fiber fracture. To evaluate the cumulative counts of AE signals, it seems that the results can be applied usefully to guarantee structural integrity and/or to the survey of destruction of the structure with heat-damage, that was made to the composite materials.

Detection and Monitoring of Fatigue Cracks in Metallic Structures Using Acoustic Emission: Routes to Quantification of Probability of Detection

2014 ◽  
Vol 891-892 ◽  
pp. 1268-1274 ◽  
Author(s):  
Daniel Gagar ◽  
Peter Foote ◽  
Phil E. Irving
Keyword(s):  
Acoustic Emission ◽  
Fatigue Crack ◽  
Fatigue Cracks ◽  
Failure Process ◽  
Probability Of Detection ◽  
Metallic Structures ◽  
Final Failure ◽  
Ae Signal ◽  
Non Destructive ◽  
Ae Signals

The performance and reliability of Structural Health Monitoring (SHM) techniques remain largely unquantified. This is in contrast to the probability of detection (POD) and sensitivity of manual non destructive inspection methods which are well characterised. In this study factors influencing the rates of emission of Acoustic Emission (AE) signals from propagating fatigue cracks were investigated. Fatigue crack growth experiments were performed in 2014 T6 aluminium sheet to observe the effects of changes in crack length, loading spectrum and sample geometry on rates of emission and the probability of detecting and locating the fatigue crack. Significant variation was found in the rates of AE signal generation during crack progression from initiation to final failure. AE signals at any point in the failure process were found to result from different failure mechanisms operating at particular stages in the failure process.

Wavelet Transform and Bispectrum Applied to Acoustic Emission Signals from Adherence Scratch-Tests on Corroded Galvanized Coatings

2006 ◽  
Vol 13-14 ◽  
pp. 83-88 ◽  
Author(s):  
Antolino Gallego ◽  
Jose F. Gil ◽  
J.M. Vico ◽  
Enrique Díaz Barriga-Castro ◽  
J.E. Ruzzante ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Acoustic Emission ◽  
Visual Inspection ◽  
Fracture Mechanisms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Galvanized Coatings ◽  
Scratch Tests ◽  
Ae Signals ◽  
Scanning Electron

Wavelet analysis and bispectrum was applied to Acoustic Emission (AE) signals from scratch tests on corroded hot-dip galvanized samples in order to achieve the detection of corrosion products in pieces non reachable by visual inspection. AE signals were correlated with the fracture mechanisms occurring during scratch tests, while the contact force increased. Results were corroborated by Scanning Electron Microscopy (SEM), Energy Dispersive X-ray spectroscopy (EDX) and X-Ray Diffraction (XRD).

Cellulose Fiber Reinforced Concrete Fracture Mechanisms and Damage Detection Using Acoustic Emission

2012 ◽  
Vol 239-240 ◽  
pp. 3-9 ◽  
Author(s):  
Yu Chen ◽  
David Bloomquist ◽  
Raphael Crowley
Keyword(s):  
Acoustic Emission ◽  
Reinforced Concrete ◽  
Ultimate Load ◽  
Cellulose Fiber ◽  
Fiber Reinforced Concrete ◽  
Fracture Mechanisms ◽  
Concrete Fracture ◽  
Fiber Breakage ◽  
Fiber Reinforced ◽  
Ae Signals

ASTM C78 standard tests for flexural strength of concrete were conducted on cellulose fiber reinforced concrete (CFRC) specimens using varying percentages of ultimate load. During testing, Acoustic Emission (AE) signals were recorded while after testing, a scanning electron microscope (SEM) was used to visually observe surface features. SEM results appear to illustrate three important stages of the fracture process: cement cracking, fiber-cement debonding, and fiber breakage/pullout. AE results were used to bound ranges for a relationship between AE amplitude and CFRC fracture mechanisms.

Использование амплитудного анализа сигналов акустической эмиссии при циклическом и статическом нагружении стальных образцов

2021 ◽  
pp. 18-26
Author(s):  
Л.Н. Степанова ◽  
М.М. Кутень ◽  
А.Л. Бобров
Keyword(s):  
Acoustic Emission ◽  
Carbon Steel ◽  
Fatigue Cracks ◽  
Low Carbon Steel ◽  
Research Data ◽  
Combined Loading ◽  
Low Carbon ◽  
Amplitude Analysis ◽  
Sensitivity Level ◽  
Ae Signals

The results of amplitude analysis of discrete acoustic emission signals from developed sources such as fatigue cracks are presented. A combined loading of low-alloy and low-carbon steel samples with stress concentrators was carried out. The analysis of the probability density of the distribution of the registered AE signals from one source by amplitudes was made. A power-behaved dependence of the frequency of distribution of the amplitude of signals with a high correlation coefficient for AE sources has been established. The research data made it possible to develop a method for restoring the total number of acoustic emission acts from a source at a given sensitivity level.

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