Advanced Acoustic Emission Techniques for Failure Analysis in concrete

摘要

In order to investigate fracture mechanisms in concrete, quantitative acoustic emission (AE) techniques can be applied. In this context a 3D localization of the recorded AE events is required. In a first step experiments were carried out to evaluate the influence of various factors on the accuracy of localization results. AE sources were either artificially generated on the surface of the specimens or obtained from loading tests. An eight channel acquisition unit was used to record AE parameters and waveforms. The quality of arrival time determination was found to be crucial for the localization and could be improved with the employment of an energy based algorithm. In a second step selected AE events, recorded during pull-out tests, were analyzed quantitatively. With the help of a relative moment tensor inversion technique AE source characteristics could be recovered.