Acoustic Emission Responses of Plasma Sprayed Ceramics During Four Point Bend Tests

2008 ◽  
pp. 44-50 ◽  
Author(s):  
Chung-Kwei Lin ◽  
Sang-Ha Leigh ◽  
Christopher C. Berndt ◽  
Robert V. Gansert ◽  
Sanjay Sampath ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Bend Tests ◽  
Point Bend ◽  
Plasma Sprayed

Acoustic Emission Studies of Thermal Barrier Coatings during Cyclic Four Point Bend Tests

1996 ◽  
Author(s):  
J. Voyer ◽  
F. Gitzhofer ◽  
M.L. Boulos ◽  
J. Dionne
Keyword(s):  
Acoustic Emission ◽  
Thermal Barrier Coatings ◽  
Peak Frequency ◽  
Thermal Barrier ◽  
Barrier Coatings ◽  
Emission Signal ◽  
Barrier Coating ◽  
Bend Tests ◽  
Point Bend ◽  
Plasma Sprayed

Abstract In this study, Acoustic Emission (AE) signals are used to monitor the degradation of plasma sprayed Thermal Barrier Coatings (TBC) using cyclic four point bend tests. Signal analysis both in time and frequency domains is carried out in order to identify the key parameters which can be used to classify the acoustic emission signals as a function of the damage mechanisms. This classification offers a mean of prediction of the long-term behavior of the thermal barrier coating based on the acoustic emission signal signature at the early stages of bench testing. The samples consist of a Nickel-based alloy blade coated with a duplex TBC made of a 150 μm thick bond coat covered with a 300 μm thick partially-stabilized zirconia coating. Tests were performed on unnotched and perpendicularly notched samples in order to discriminate the AE from perpendicular cracks. Two broadband transducers are used for acquisition of acoustic emission signals. Measuring the time between signal detection by each of the two transducers provides a means of determination of the location of the source of the acoustic signals. A classification of the signals based on their energy and their maximum peak frequency is presented. A comparison is made between the degradation mechanisms of TBC under thermal cycling conditions that were presented elsewhere (1) and the results of four point bend tests presented here.

Acoustic Emission Studies of Alumina-13% Titania Free-Standing Forms during Four-Point Bend Tests

2005 ◽  
Vol 80 (9) ◽  
pp. 2382-2394 ◽  
Author(s):  
Chung-Kwei Lin ◽  
Christopher C. Berndt ◽  
Sang-Ha Leigh ◽  
Kenji Murakami
Keyword(s):  
Acoustic Emission ◽  
Free Standing ◽  
Bend Tests ◽  
Point Bend ◽  
Emission Studies

scholarly journals Deformation of Plasma Sprayed Thermal Barrier Coatings

1999 ◽  
Author(s):  
Ufuk Senturk ◽  
Rogerio S. Lima ◽  
Carlos R. C. Lima ◽  
Christopher C. Berndt
Keyword(s):  
Acoustic Emission ◽  
Composite System ◽  
Coating Properties ◽  
Failure Characteristics ◽  
Deformation Curves ◽  
Metallic Bond ◽  
Point Bend ◽  
Plasma Sprayed ◽  
Thermally Sprayed

The deformation behavior of thermally sprayed partially stabilized zirconia (PSZ) coatings are investigated using Hertzian indentation and four-point bend testing, with in situ acoustic emission monitoring. The experimental deformation curves, together with the corresponding acoustic emission responses and the fracture properties of the material are used in defining the deformation characteristics of the coating (ceramic overlay with metallic bond coal where applicable) and substrate composite system. Experiments are aimed in examining the influence of the bond coat and the coating properties on the form of deformation. Substrate temperature and pauses during spraying are demonstrated to strongly effect the coating properties and the resulting fracture/failure characteristics of the composite system.

Investigation Of Cracking Mechanisms Of Plasma Sprayed Alumina-13% Titania By Acoustic Emission

1995 ◽  
Vol 409 ◽  
Author(s):  
C.K. Lin ◽  
S.H. Leigh ◽  
R.V. Gansert ◽  
K. Murakami ◽  
S. Sampath ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
High Amplitude ◽  
High Energy ◽  
Physical Models ◽  
Free Standing ◽  
Water Stabilized Plasma ◽  
Heat Treated ◽  
Cracking Mechanisms ◽  
Point Bend ◽  
Plasma Sprayed

AbstractFree standing alumina-13% titania samples were manufactured using high power water stabilized plasma spraying. Heat treatment was performed at 1450°C for 24 hours and then at 1100°C for another 24 hours. Four point bend tests were performed on the as-sprayed and heat-treated samples in both cross section and in-plane orientations with in situ acoustic emission monitoring to monitor the cracking during the tests. Catastrophic failure with less evidence of microcracking was observed for as-sprayed samples. Energy and amplitude distributions were examined to discriminated micro- and macro-cracks. It was found that the high energy (> 100) and high amplitude (say > 60 dB) responses can be characterized as macro-cracks. Physical models are proposed to interpret the AE responses under different test conditions so that the cracking mechanisms can be better understood.

Deformation of Plasma Sprayed Thermal Barrier Coatings

2000 ◽  
Vol 122 (3) ◽  
pp. 387-392 ◽  
Author(s):  
Ufuk Senturk ◽  
Rogerio S. Lima ◽  
Carlos R. C. Lima ◽  
Christopher C. Berndt
Keyword(s):  
Acoustic Emission ◽  
Bond Coat ◽  
Composite System ◽  
Coating Properties ◽  
Failure Characteristics ◽  
Deformation Curves ◽  
Point Bend ◽  
Plasma Sprayed ◽  
Thermally Sprayed

The deformation behavior of thermally sprayed partially stabilized zirconia (PSZ) coatings are investigated using Hertzian indentation and four-point bend testing, with in situ acoustic emission monitoring. The experimental deformation curves, together with the corresponding acoustic emission responses and the fracture properties of the material are used in defining the deformation characteristics of the coating (ceramic overlay with metallic bond coat where applicable) and substrate composite system. Experiments are aimed in examining the influence of the bond coat and the coating properties on the form of deformation. Substrate temperature and pauses during spraying are demonstrated to strongly effect the coating properties and the resulting fracture/failure characteristics of the composite system. [S0742-4795(00)02503-5]

On the Reproducibility of Transducer Coupling for Acoustic Emission Testing

2006 ◽  
Vol 13-14 ◽  
pp. 117-124 ◽  
Author(s):  
James J. Hensman ◽  
C.V. Cristodaro ◽  
Gareth Pierce ◽  
Keith Worden
Keyword(s):  
Acoustic Emission ◽  
Test Results ◽  
Coupling Condition ◽  
Waveform Data ◽  
Three Point Bending ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Acoustic Emission Test ◽  
Point Bend ◽  
Ultrasonic Propagation

An acoustic emission test was simulated using a three point bend specimen and an artificial AE source. Waveform data was recorded as the sample was cyclically loaded in three point bending, and the cross correlation coefficient of the waveforms was used to measure the repeatability of the test. Results were twofold: the stress state of a specimen affects the ultrasonic propagation therein; and the coupling condition of a transducer may not remain constant during a test.

Investigation of the Staging of Damage Accumulation in Polymer Composite Materials during Bending and Tensile Tests

2021 ◽  
Vol 887 ◽  
pp. 116-122
Author(s):  
A.A. Bryansky ◽  
O.V. Bashkov ◽  
Daria P. Malysheva ◽  
Denis B. Solovev
Keyword(s):  
Acoustic Emission ◽  
Composite Materials ◽  
Polymer Composite ◽  
Loading Rate ◽  
Tensile Tests ◽  
Mechanical Tests ◽  
Rate Effect ◽  
Polymer Composite Materials ◽  
Static Tension ◽  
Point Bend

The paper presents the results of the study of registered acoustic emission (AE) parameters during static deformation and damaging of polymer composite materials (PCM). Mechanical tests were done by a static tension and a static three-point bend, accompanied by an acoustic emission method. The assessment of the loading rate effect on defects formation processes was done by additional static tension test at rate equal half of recommended by the standard and static three-point bend test at rate ten times lower than that calculated by the standard. Clustering by frequency components of the recorded AE signals with a self-organizing Kohonen map was performed. The characteristics of the types of PCM structure damage by the centroids of the obtained clusters are given. Based on the clusters accumulation during mechanical tests, the stages of damage formation for static tension and static three-point bend, the loading rate effect on the process of damage formation are described.

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