Localisation of Acoustic Emission in Reinforced Concrete using Heterogeneous Velocity Models
| Autor: | Gollob, Stephan, Vogel, Thomas |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2014 |
| Předmět: |
PROPAGATION SPEED OF VIBRATIONS IN INHOMOGENEOUS MEDIA (ACOUSTICS)
Physics CRACKS (BUILDING MATERIALS) SCHALLEMISSIONSVERFAHREN (MATERIALPRÜFUNG) ACOUSTIC EMISSION AE (MATERIALS TESTING) BEWEHRTER BETON (BAUSTOFFE) SCHALLAUSBREITUNG IN INHOMOGENEN MEDIEN (AKUSTIK) RISSE (BAUSTOFFE) REINFORCED CONCRETE (BUILDING MATERIALS) 0211 other engineering and technologies 02 engineering and technology 01 natural sciences ddc:690 021105 building & construction 0103 physical sciences ddc:530 Buildings 010301 acoustics |
| Zdroj: | 31st Conference of the European Working Group on Acoustic Emission (EWGAE) |
| DOI: | 10.3929/ethz-a-010265299 |
| Popis: | Acoustic emission analysis (AEA) has become a promising method to monitor the change in the condition of concrete structures. The research project aims at investigating the influence of reinforcement and cracks on wave propagation. Therefore localisation algorithms using heterogeneous velocity models are developed. Taking the heterogeneity of concrete and the influence of reinforcement into account will improve the source localisation accuracy. Until now it is common to use homogeneous velocity models to localize the acoustic emission (AE) source. As a consequence effects of heterogeneity especially reinforcements and cracks cannot be considered. Therefore a new numerical reinforced concrete model (NRCM) is developed which is used to investigate the influence of reinforcements and cracks on the wave propagation path and their influence on the signal recorded by piezoelectric sensors. As a rule the reinforcement layout is known. Other wise the layout can be determined using acoustic tomography for example. The only information provided by the velocity model of the specimen is the wave velocity of each voxel depending on the assigned material. A localization method is modified for processing these heterogeneous velocity models. The source location is calculated iteratively. The difference between the calculated signal arrival time and the measured arrival time is used to update the estimated source location and time. It is common to use one homogeneous wave velocity the distance between the estimated source location and a sensor as well as the estimated source time to compute the calculated arrival time. Using the heterogeneous velocity model the wave travel time between the estimated source location and a sensor can be calculated as sum of the wave travel times through every voxel assuming a linear wave propagation path. An acoustic tomogram could be updated using the data recorded by the sensors monitoring the specimen. Hence also the velocity model could be updated. Cracks could be considered in the velocity model even if they occur after the preliminary tomography. The combination of three dimensional acoustic tomography with AE analysis is a novel and promising approach. |
| Databáze: | OpenAIRE |
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