ISSN:
1662-8985
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Acoustic Emission (AE) testing in concrete structures shows great potential formonitoring and assessing the health condition of structures. Source location is normally based onthe arrival times of transient signals, the simplest method is known as the Time of Arrival (TOA)method, where the location of the damage can be determined from the arrival time of the event attwo or more sensors. When using this method, the wave velocity of the signals that propagatethrough the material needs to be determined. Homogenous materials, such as steel, have welldefinedvelocities, but in non-homogeneous materials such as concrete the wave velocity is moredifficult to predict. This makes the use of a single wave velocity as required in the TOA methodvery difficult due to the variety of wave velocities obtained, especially for large structures.This paper explores wave propagation in concrete structures over a variety of source to sensordistances. Experiments were performed on a reinforced concrete beam and a reinforced concreteslab, using an Hsu-Nelsen (H-N) Source. It is found that, in general, as the source to sensor distanceincreases, the wave velocity decreases. The presence of longitudinal and transverse waves isdemonstrated and the influence of the part of the waveform used for temporal measurement isexplored. In order to provide a practical approach to velocity determination, different thresholds areinvestigated and the results are discussed in relation to the wave modes present
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/01/39/transtech_doi~10.4028%252Fwww.scientific.net%252FAMR.13-14.205.pdf
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