Fatigue behavior and damage analysis by the acoustic emission technique of cross-ply laminates under tensile loading

2017 ◽  
Vol 13 (2) ◽  
pp. 150-164
Author(s):  
Imen Ben Ammar ◽  
Abderrahim El Mahi ◽  
Chafik Karra ◽  
Rachid El Guerjouma ◽  
Mohamed Haddar
Keyword(s):  
Acoustic Emission ◽  
Mechanical Behavior ◽  
Fatigue Behavior ◽  
Glass Fibers ◽  
Tensile Tests ◽  
Hybrid Fibers ◽  
Content Type ◽  
Laminated Materials ◽  
Ae Signals ◽  
Damage Investigation

Purpose The purpose of this paper is to study the mechanical behavior in fatigue tensile mode of different cross-ply laminates constituted of unidirectional carbon fibers, hybrid fibers and glass fibers in an epoxy matrix; and to identify and characterize the local damage in the laminated materials with the use of the acoustic emission (AE) technique. Design/methodology/approach The tests in the fatigue mode permitted the determination of the effect of the stacking sequences, thickness of 90° oriented layers and reinforcement types on the fatigue mechanical behavior of the laminated materials. The damage investigation in those materials is reached with the analysis of AE signals collected from fatigue tensile tests. Findings The results show the effects of reinforcement type, stacking sequences and thicknesses ratio of 90° and 0° layers on the mechanical behavior. A cluster analysis of AE data is achieved and the resulting clusters are correlated with the damage mechanism of specimens under loading tests. Originality/value The analysis of AE signals collected from tensile tests of the fatigue failure load allows the damage investigation in different types of cross-ply laminates which are differentiated by the reinforcement type, stacking sequences and thicknesses ratio of 90° and 0° layers.

Mechanical behaviour and damage evaluation by acoustic emission of composite materials

2013 ◽  
Vol 9 (1) ◽  
pp. 100-115 ◽  
Author(s):  
I. Ben Ammar ◽  
A. El Mahi ◽  
C. Karra ◽  
R. El Guerjouma ◽  
M. Haddar
Keyword(s):  
Acoustic Emission ◽  
Mechanical Behaviour ◽  
Failure Load ◽  
Glass Fibers ◽  
Damage Mechanism ◽  
Hybrid Fibers ◽  
Emission Data ◽  
Content Type ◽  
Static Tensile ◽  
Damage Investigation

PurposeThe aim of the present study is to investigate the mechanical behaviour of cross‐ply laminates under static tensile and buckling loading. Different cross‐ply laminates constituting of carbon fibers (CFRP), hybrid fibers (HFRP) and glass fibers (GFRP) in an epoxy matrix were considered. This work is also interested in identifying and characterizing the local damage in the composites with the use of acoustic emission method (AE).Design/methodology/approachThe cross‐ply laminates are differentiated by the stacking sequences, thickness of 90° oriented layers and reinforcement. They are subjected to the static tensile and buckling load. The damage investigation is reached by the analysis of acoustic emission signals collected from static buckling tests.FindingsThe results show the effects of reinforcement type, stacking sequences and thicknesses ratio of 90° and 0° layers on the stiffness, failure load and displacement. A cluster analysis of acoustic emission data is achieved and the results are correlated to the damage mechanism of specimens under buckling tests.Originality/valueThe analysis of acoustic emission signals collected from static buckling tests under loading levels of 40, 60 and 100 per cent of the static failure load allows the damage investigation in cross‐ply laminates.

Reciprocating compressor valve damage estimation under varying speeds through the acoustic emission technique

2019 ◽  
Vol 10 (5) ◽  
pp. 621-633
Author(s):  
Hoi-Yin Sim ◽  
Rahizar Ramli ◽  
Ahmad Saifizul
Keyword(s):  
Acoustic Emission ◽  
Regression Analysis ◽  
Flow Rate ◽  
Reciprocating Compressor ◽  
Damage Estimation ◽  
Content Type ◽  
Air Compressor ◽  
Ae Signal ◽  
Valve Opening ◽  
Ae Signals

Purpose The purpose of this paper is to examine the effect of reciprocating compressor speeds and valve conditions on the roor-mean-square (RMS) value of burst acoustic emission (AE) signals associated with the physical motion of valves. The study attempts to explore the potential of AE signal in the estimation of valve damage under varying compressor speeds. Design/methodology/approach This study involves the acquisition of AE signal, valve flow rate, pressure and temperature at the suction valve of an air compressor with speed varrying from 450 to 800 rpm. The AE signals correspond to one compressor cycle obtained from two simulated valve damage conditions, namely, the single leak and double leak conditions are compared to those of the normal valve plate. To examine the effects of valve conditions and speeds on AE RMS values, two-way analysis of variance (ANOVA) is conducted. Finally, regression analysis is performed to investigate the relationship of AE RMS with the speed and valve flow rate for different valve conditions. Findings The results showed that AE RMS values computed from suction valve opening (SVO), suction valve closing (SVC) and discharge valve opening (DVO) events are significantly affected by both valve conditions and speeds. The AE RMS value computed from SVO event showed high linear correlation with speed compared to SVC and DVO events for all valve damage conditions. As this study is conducted at a compressor running at freeload, increasing speed of compressor also results in the increment of flow rate. Thus, the valve flow rate can also be empirically derived from the AE RMS value through the regression method, enabling a better estimation of valve damages. Research limitations/implications The experimental test rig of this study is confined to a small pressure ratio range of 1.38–2.03 (free-loading condition). Besides, the air compressor is assumed to be operated at a constant speed. Originality/value This study employed the statistical methods namely the ANOVA and regression analysis for valve damage estimation at varying compressor speeds. It can enable a plant personnel to make a better prediction on the loss of compressor efficiency and help them to justify the time for valve replacement in future.

scholarly journals Damage evolution in wood – pattern recognition based on acoustic emission (AE) frequency spectra

Holzforschung ◽  
2015 ◽  
Vol 69 (3) ◽  
pp. 357-365 ◽  
Author(s):  
Franziska Baensch ◽  
Markus G.R. Sause ◽  
Andreas J. Brunner ◽  
Peter Niemz
Keyword(s):  
Pattern Recognition ◽  
Acoustic Emission ◽  
Cluster Formation ◽  
Low Frequency ◽  
Tensile Tests ◽  
Most Probable Number ◽  
Frequency Spectra ◽  
Probable Number ◽  
Ae Signal ◽  
Ae Signals

Abstract Tensile tests on miniature spruce specimens have been performed by means of acoustic emission (AE) analysis. Stress was applied perpendicular (radial direction) and parallel to the grain. Nine features were selected from the AE frequency spectra. The signals were classified by means of an unsupervised pattern recognition approach, and natural classes of AE signals were identified based on the selected features. The algorithm calculates the numerically best partition based on subset combinations of the features provided for the analysis and leads to the most significant partition including the respective feature combination and the most probable number of clusters. For both specimen types investigated, the pattern recognition technique indicates two AE signal clusters. Cluster A comprises AE signals with a relatively high share of low-frequency components, and the opposite is true for cluster B. It is hypothesized that the signature of rapid and slow crack growths might be the origin for this cluster formation.

Determining the feasibility of identifying creep rupture of stainless steel cladding tubes on-line using acoustic emission technique

2015 ◽  
Vol 6 (3) ◽  
pp. 410-418
Author(s):  
N Mahendra Prabhu ◽  
K.A. Gopal ◽  
S. Murugan ◽  
T.K. Haneef ◽  
C. K. Mukhopadhyay ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Acoustic Emission ◽  
Creep Rupture ◽  
Acoustic Emission Technique ◽  
Content Type ◽  
Fuel Pin ◽  
On Line ◽  
Clad Tube ◽  
Non Destructive ◽  
Ae Signals

Purpose – The purpose of this paper is to determine the feasibility of identifying the creep rupture of reactor cladding tubes using acoustic emission technique (AET). Design/methodology/approach – The creep rupture tests were carried out by pressuring stainless steel capsules upto 6 MPa at room temperature and then heating continuously in a furnace upto rupture. The acoustic emission (AE) signals generated during the creep rupture tests were recorded using a 150 kHz resonant sensor and analysed using AE Win software. Findings – When rupture occurs in the pressurized capsule tube representing the cladding tube, AE sensor attached to a waveguide captures the mechanical disturbance from the capsule and these data can be advantageously used to identify the creep rupture event of the cladding tube. Practical implications – The creep rupture data of fuel clad tube is very important in design and for smooth operation of nuclear reactors without fuel pin failure in reactors. Originality/value – AE is an advanced non-destructive evaluation technique. This technique has been successfully applied for on-line monitoring of creep rupture of the reactor cladding tube which otherwise could be detected by thermocouple readings only.

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.

Akustische Emissionsmessung an Papier/Acoustic emission analysis on paper – Identification of failure mechanisms in the forming of sustainable fibre materials

2020 ◽  
Vol 110 (10) ◽  
pp. 650-655
Author(s):  
Julian Mushövel ◽  
Torben Völker ◽  
Peter Groche
Keyword(s):  
Acoustic Emission ◽  
Tensile Test ◽  
Failure Mechanisms ◽  
Tensile Tests ◽  
Test Rig ◽  
Emission Analysis ◽  
Ae Signals ◽  
Acoustic Emission Analysis

Die Faserbewegungen und mikromechanischen Mechanismen während der Umformung von Papier sind bis heute nicht gänzlich geklärt. In dieser Arbeit werden die Einsatzmöglichkeiten der akustischen Emissionsmessung (AE-Messung) zur Analyse des Faserverhaltens untersucht. Zu diesem Zweck werden Zugversuche mit Papierproben an einem Miniaturzugprüfstand durchgeführt. Zusammenhänge zwischen mikromechanischen Prozessen im Papier und den Peak-Frequenzen der detektierten AE-Signale werden aufgedeckt.   The fibre movements and micromechanical mechanisms during the forming of paper are still not fully understood. This paper investigates the application of acoustic emission analysis (AE analysis) for the characterization of fibre behaviour. For this purpose, tensile tests with paper samples are performed on a miniature tensile test rig. Correlations between micromechanical processes in the paper and the peak-frequencies of the detected AE signals are found.

Acoustic Emission Test on Steel/Composite and Steel/Composite/Steel Built-Up Sections

2011 ◽  
Author(s):  
Rushie Ghimire ◽  
Gary Anderson ◽  
Fereidoon Delfanian
Keyword(s):  
Acoustic Emission ◽  
Tensile Tests ◽  
Glue Line ◽  
Stress And Strain ◽  
Steel Component ◽  
Cumulative Count ◽  
Steel Composite ◽  
Acoustic Emission Test ◽  
Ae Signals ◽  
Composite Steel

Acoustic Emission (AE) has been widely used to monitor and inspect built-up steel/composite sections; primarily at the glue line. AE testing was conducted on steel-composite (SC) and steel-composite-steel (SCS) built-up sections to determine the glue line failure and damage sustained by the inner layer of the built-up section by putting the sensors on the inner and outer layers of the built-up sections. The straight specimens of steel/composite and steel/composite/steel were tested with load applied to only one steel layer. The AE sensors were placed on the outer steel component so that detected signals traveled through the loaded steel, glue lines, and the composite or the loaded steel component, two glue lines, composite and unloaded steel components of the built-up section(s). The AE signals received by the sensors placed on the loaded steel in tension was compared to signals of sensors placed directly opposite on the unloaded steel or composite to determine the effect the steel/composite and steel/composite/steel built-up sections had on the signal. AE signals were also compared to signals generated during tensile tests of steel specimens only and composite specimens only. AE parameters like amplitude, hits, counts, frequency, cumulative count, and rise time of the AE signals were recorded, analyzed, and compared. AE parameters were also compared to traditional material properties (like yield and failure stress and strain). Tested specimens were examined with a microscope and observations were compared and analyzed relative to AE and material parameters, and reported.

Structural integrity assessment of H2S storage tanks using acoustic emission and ultrasonic techniques

2015 ◽  
Vol 6 (1) ◽  
pp. 73-89 ◽  
Author(s):  
C. K. Mukhopadhyay ◽  
T.K. Haneef ◽  
T. Jayakumar ◽  
G.K. Sharma ◽  
B.P.C. Rao
Keyword(s):  
Acoustic Emission ◽  
Heavy Water ◽  
Structural Integrity ◽  
Ultrasonic Inspection ◽  
Storage Tanks ◽  
Content Type ◽  
Water Plant ◽  
Ultrasonic Techniques ◽  
Ae Signals ◽  
Point Type

Purpose – The purpose of this paper is to present the results of acoustic emission (AE) and ultrasonic inspection of two H2S storage tanks carried out in a heavy water plant, in order to characterize point type defects observed during earlier ultrasonic inspection and to ensure that these defects are not growing during hydrotesting of the tanks. Design/methodology/approach – Using multiple AE sensors and AE source location methodology, the entire tank could be covered to detect and locate any dynamic sources of AE associated with local plastic deformation and/or growing discontinuities from any part of the tank during the hydrotest. For confirmation of the results obtained by AE, ultrasonic inspection on the tanks and on virgin plates from which the tanks were manufactured, were carried out. Findings – The AE signals generated during first pressurisation are attributed to the micro yielding of the material of the tanks. A few scattered AE events were observed at a few locations during the hydrotesting of the tanks and these are due to structural and rubbing noise. During hold periods and repressurising cycle of the hydrotesting, no detectable AE events were observed and this confirmed the absence of any growing discontinuity in the tanks during the hydrotesting. Ultrasonic inspection on the tanks and on virgin plates confirmed that the point type defects detected are manufacturing defects and not formed during service life. Practical implications – The combined results from AE and ultrasonic techniques confirmed the structural integrity of the tanks and ensured their healthiness for continued operation. Originality/value – The paper brings out the use of AE and ultrasonic techniques for monitoring hydrotesting of storage tanks of a heavy water plant. The storage tanks where point type defect indications were reported during previous ultrasonic inspection and whether these defects are growing during hydrotesting of the tanks or not, were required to be known before the tanks are put in to further service. AE signals collected during pressurising and repressurising cycles of the hydrotest and subsequent inspection by ultrasonic confirmed the vessels to be free from growing defects during the hydrotest and provided baseline data for future inspection.

scholarly journals Damage evolution in wood: synchrotron radiation micro-computed tomography (SRμCT) as a complementary tool for interpreting acoustic emission (AE) behavior

Holzforschung ◽  
2015 ◽  
Vol 69 (8) ◽  
pp. 1015-1025 ◽  
Author(s):  
Franziska Baensch ◽  
Michaela Zauner ◽  
Sergio J. Sanabria ◽  
Markus G.R. Sause ◽  
Bernd R. Pinzer ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Acoustic Emission ◽  
Synchrotron Radiation ◽  
Damage Evolution ◽  
Tensile Tests ◽  
High Time Resolution ◽  
Micro Computed Tomography ◽  
Crack Evolution ◽  
Microscopic Scale ◽  
Ae Signals

Abstract Tensile tests of miniature spruce wood specimens have been performed to investigate the damage evolution in wood at the microscopic scale. For this purpose, the samples were stepwise tensile loaded in the longitudinal (L) and radial (R) directions and the damage evolution was monitored in real-time by acoustic emission (AE) and synchrotron radiation micro-computed tomography (SRμCT). This combination is of outstanding benefit as SRμCT monitoring provides an insight on the crack evolution and the final fracture at microscopic scale, whereas AE permits the detection of the associated accumulation and interaction of single damage events on all length scales with high time resolution. A significant drawback of the AE testing of wood has been overcome by means of calibrating the AE amplitudes with the underlying crack length development. Thus, a setup-dependent and wood species-dependent calibration value was estimated, which associates 1 μm2 crack area generating of 0.0038 mV in the detected AE amplitude. Furthermore, for both L and R specimens, AE signals were classified into two clusters by using a frequency-based approach of unsupervised pattern recognition. The shares of AE signals of both clusters correlate with the ratio of the relative crack area of the interwall and transwall cracks gained from the fractographic analysis of SRμCT scans.

scholarly journals Acoustic Emission Characteristics and Damage Evolution of Rock under Different Loading Modes

Energies ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3649
Author(s):  
Ersheng Zha ◽  
Ru Zhang ◽  
Zetian Zhang ◽  
Ting Ai ◽  
Li Ren ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Fracture Surface ◽  
Tensile Stress ◽  
Energy Release ◽  
Failure Modes ◽  
Failure Process ◽  
Tensile Tests ◽  
Single Fracture ◽  
Loading Modes ◽  
Ae Signals

To study the evolution of acoustic emission (AE) parameters and the differences in the fracturing and failure process of rocks under different loading modes, AE signals of marble were detected during uniaxial compression tests (UCTs), direct tensile tests (DTTs) and indirect tensile tests (ITTs) in this paper. Then, the temporal and spatial evolution of the AE parameters and damage development of rock under different loading modes were analyzed. The results showed that the sequence of total AE events and AE counts under different loading modes was UCT > DTT > ITT. In the DTT and ITT, the energy release of AE signals was concentrated at the peak stress and weakened rapidly afterward, whereas in the UCT, there were still a large number of AE signals accompanied by violent AE energy release during the postpeak stage. The generation mechanism of AE sources in rock and the corresponding failure modes were different under different loading modes. In the UCT, the multiple cleavage fractures were mainly caused by compression-induced fracturing. In the DTT, the single fracture surface was generated by tensile stress, whereas in the ITT, compressive-tensile stress was applied to the fracture surface. In addition, the stress levels at which the b-value and the spatial fractal dimension Ds of AE events decreased dramatically were consistent under the different loading modes, and the sequence was UCT < DTT < ITT. According to the changes in AE parameters during the whole process of rock deformation and failure, the first and second precursor points before failure were defined to distinguish the development of microfracture damage and failure processes in rocks under the different loading modes. The above results have certain significance for future studies on the monitoring of surrounding rock instability and failure prediction.

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