Similarity matrices as a new feature for acoustic emission analysis of concrete

The acoustic emission signal contains information about the fracture process which emits the signal and its travel path to the recording sensor. This is expressed in the signal's shape. Estimating the cross correlation function or the magnitude squared coherence function between several signals of clustered events, leads to information about the similarity of these signals, i.e. about the fracture processes and the travel paths. It is possible to use the signal's original shape or to calculate the envelope by the Hilbert transform or to use only a small window around the onset of the signal. With the help of a similarity matrix it is possible to investigate very quickly changes in the physical properties of the ray path of events from one cluster. I.e. changes concerning the dimension of the fracture area or internal stress redistributions become visible. The similarity analysis can be used to identify true acoustic emissions from artefacts and it can be used to reduce the number of events which must be localized to characterize the failure behaviour. Furthermore, the results can be surveyed by other fracture analysis procedures.

[1]  Burkhard Buttkus.  Spektralanalyse und Filtertheorie , 1991 .

[2]  T. Meier,et al.  Similarity of waveforms and relative relocalisation of the earthquake swarm 1997/1998 near Werdau , 2003 .

[3]  Hansruedi Maurer,et al.  Microearthquake cluster detection based on waveform similarities, with an application to the western Swiss Alps , 1995 .

[4]  Christian U. Grosse,et al.  Quantitative zerstörungsfreie Prüfung von Baustoffen mittels Schallemissionsanalyse und Ultraschall , 1996 .

[5]  E. O. Brigham,et al.  The Fast Fourier Transform , 1967, IEEE Transactions on Systems, Man, and Cybernetics.

[6]  Stefan Köppel,et al.  Schallemissionsanalyse zur Untersuchung von Stahlbetontragwerken , 2002 .

[7]  Hans W. Reinhardt,et al.  Shear of structural concrete members and pure mode II testing , 1997 .

[8]  J. Pechmann,et al.  Constraints on relative earthquake locations from cross-correlation of waveforms , 1987 .

[9]  U. Wegler,et al.  Scattering behaviour at Merapi volcano (Java) revealed from an active seismic experiment , 2001 .

[10]  Christian U. Grosse,et al.  Improvements of AE technique using wavelet algorithms, coherence functions and automatic data analysis , 2003 .

[11]  William L. Ellsworth,et al.  Monitoring velocity variations in the crust using earthquake doublets: An application to the Calaveras Fault, California , 1984 .

[12]  Shilang Xu,et al.  Experimental determination of KIIC of normal strength concrete , 1998 .

[13]  Charlotte A. Rowe,et al.  Automatic Phase Pick Refinement and Similar Event Association in Large Seismic Datasets , 2000 .