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.

Acoustic Emission Testing and Structural Evaluation of Seamless, Steel Tubes in Compressed Gas Service

1986 ◽  
Vol 108 (2) ◽  
pp. 234-240 ◽  
Author(s):  
P. R. Blackburn ◽  
M. D. Rana
Keyword(s):  
Acoustic Emission ◽  
Test Method ◽  
Department Of Transportation ◽  
Structural Evaluation ◽  
Emission Testing ◽  
Industrial Gases ◽  
Acoustic Emission Testing ◽  
Acoustic Emission Test ◽  
Seamless Steel Tubes ◽  
Seamless Steel

Tube trailers are used in the distribution of industrial gases. The tubes, which are seamless steel, measure 22-in. diameter, about 1/2-in. wall, and 34 ft long. The U. S. Department of Transportation mandates periodic re-tests of tubes every 5 yr. Acoustic emission re-tests have been substituted for hydrostatic re-tests. This paper presents an analysis of flaws using fracture mechanics methods and establishes a maximum allowable flaw depth. It describes the acoustic emission test method and presents some typical results. Also, some discussion of the hydrostatic re-test is included.

Acoustic Emission Testing of a Process Reactor

2005 ◽  
Author(s):  
Simon Yuen ◽  
David Wang ◽  
Paul Benedictus
Keyword(s):  
Acoustic Emission ◽  
Slag Inclusion ◽  
Thick Wall ◽  
Operating Pressure ◽  
Weld Overlay ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Acoustic Emission Test ◽  
Ae Signals

An Acoustic Emission Test (AET) was performed on a hydrocarbon processing reactor to inspect for environmental cracking in 2000. The thick-wall reactor was built in 1965, fabricated from 2.25Cr-1Mo steel with Type 347 stainless steel weld overlay. Past internal inspections of the reactor using liquid penetrant had revealed cracking at internal ring supports. Such inspections were exhaustive and time consuming. The AET was performed to achieve 100% inspection coverage of the reactor and to identify suspect areas for further evaluation. The test included over-pressurization of the reactor to 10% above its operating pressure before the shutdown and the actual cooling of the reactor from 745°F to 300°F. Upon completion of the acoustic emission (AE) monitoring, significant indications were identified, most noticeably at the reactor dump nozzle and the bottom head to shell weld. Both of these were in areas that had not been inspected previously. Follow-up inspections, including external ultrasonic and internal liquid penetrant test, were performed to investigate all the areas of significant AE activities. The results showed internal cracks isolated to the weld overlay at the catalyst dump nozzle and a 12” long weld slag inclusion in the bottom head to shell weld. A methodology was developed also to evaluation criticality of AE signals during different stages of AE test.

Detection of the Propagation of Defects in Pressurized Pipes Through the Acoustic Emission Technique Using Artificial Neural Networks

2006 ◽  
Author(s):  
Sergio Damasceno Soares ◽  
Romeu Ricardo da Silva
Keyword(s):  
Neural Networks ◽  
Acoustic Emission ◽  
Artificial Neural Networks ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Emission Testing ◽  
Acoustic Emission Testing ◽  
Artificial Neural ◽  
Acoustic Emission Test ◽  
Non Destructive

The acoustic emission test has distinguished relevance in non-destructive testing and, therefore, existing research abound at present aiming at the improvement of the reliability of their results. In this work, the methodologies and the results obtained in a study performed are presented to implement pattern classifiers by using artificial neural networks, aiming at the propagation of existing defects in pressurized pipes by means of Acoustic Emission testing (AE). Parameters that are characteristic of AE signals were used as input data for the classifiers. Several tests were performed and the classification performances were in the range of 92% for most of the instances analyzed. Studies of parameter relevance were also performed and showed that only a few of the parameters are actually important for the separation of classes of signals corresponding to No Propagation (NP) of defects and Propagation (P) of defects. The results obtained are pioneering in this type of research and encouraged the present publication.

scholarly journals Characterization of acoustic emission signals under 3-point bending test

2021 ◽  
Vol 1201 (1) ◽  
pp. 012034
Author(s):  
N B G Nguyen ◽  
H G Lemu ◽  
O Gabrielsen ◽  
I El-Thalji
Keyword(s):  
Acoustic Emission ◽  
Input Data ◽  
Bending Test ◽  
Three Point Bending ◽  
Emission Testing ◽  
Signal Characteristics ◽  
Master's Thesis ◽  
Acoustic Emission Testing ◽  
Existing Data

Abstract This paper summarizes a master’s thesis project which explored whether the characteristics of Acoustic Emission Testing (AET) signals can be used to detect yielding in steel samples undergoing a three-point bending test. A subset of existing data from a three-point bending test was exported and used as input. Data was processed by utilizing and developing tools to visualize and analyse the signal characteristics, primarily through a parameter-based approach. Signals were visualized, and parameters were optimized to identify and classify signal types. According to the obtained results, some limitations on classification were experienced due to the length of the hit data recorded. Though the work reported in this article lead to a reliable method for detecting yielding, the developed algorithms were not successful in identifying characteristics that could be used to detect yielding.

scholarly journals Acoustic Emission Testing and Ib-Value Analysis of Ultraviolet Light-Irradiated Fiber Composites

2021 ◽  
Vol 11 (14) ◽  
pp. 6550
Author(s):  
Doyun Jung ◽  
Wonjin Na
Keyword(s):  
Acoustic Emission ◽  
Irradiation Time ◽  
Tensile Load ◽  
Failure Behavior ◽  
Value Analysis ◽  
Emission Testing ◽  
Final Failure ◽  
Acoustic Emission Testing ◽  
Woven Glass Fiber ◽  
Ae Signals

The failure behavior of composites under ultraviolet (UV) irradiation was investigated by acoustic emission (AE) testing and Ib-value analysis. AE signals were acquired from woven glass fiber/epoxy specimens tested under tensile load. Cracks initiated earlier in UV-irradiated specimens, with a higher crack growth rate in comparison to the pristine specimen. In the UV-degraded specimen, a serrated fracture surface appeared due to surface hardening and damaged interfaces. All specimens displayed a linearly decreasing trend in Ib-values with an increasing irradiation time, reaching the same value at final failure even when the starting values were different.

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