| Autor: |
Koschitzki, R., Schacht, G., Schneider, D., Marx, S., Maas, H.-G. |
| Zdroj: |
Proceedings of SPIE; June 2011, Vol. 8085 Issue: 1 p80850I-80850I-8, 727659p |
| Abstrakt: |
This paper focuses on space- and time-resolved crack detection in concrete structures by combining photogrammetric techniques with acoustic emission analysis. For the photogrammetric measurements, the surface of reinforced concrete members is textured with a random pattern. A consumer-grade digital camera is used to observe the region of interest during the loading tests. In a sequence of images, cracks are visualized by detecting discrepancies in local displacement vector fields, which are obtained from matching algorithms applied to consecutive images. Critical areas of concrete samples are additionally equipped with several acoustic emission sensors to monitor the crack formation and propagation by acoustic emission analysis. The parameter-based method is used to record specific parameters in real time and enables the distinction between bending or shear cracks depending on the signal energy and duration. During the loading tests, information about the crack prolongation is used to derive the time of transition from stable to unstable phase. The acoustically detected shear cracks are monitored in the images to track growth and to stop the experiment before a critical bearing status is reached. Thus, shear cracks can be localized temporally and locally on the surface and inside the structure. In a next step, the detected cracks have to be checked for certain properties providing information about the condition of the structure. Indicators with high level significance referring to structures with no or low advance notice of failure constitute a focal point of further research. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
|
