Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Eine Plattform für die Wissenschaft: Bauingenieurwesen, Architektur und Urbanistik
Application of acoustic techniques in the evaluation of heterogeneous building materials
The accuracy of the reconstruction of the longitudinal seismic velocity distribution, anomaly localisation and resolution in the tomographic process can be improved by applying the proposed new experimental procedure based on the calculation of the cross-correlation function (CCF). The interpretation of the cross-correlograms relating to several ancient columns of the investigated historical Church of San Bartolomeo and deduced from the previously described processing sequence has been an objective constraint to precisely define the location and the geometry of anomaly zones of the transit times of the longitudinal wave rays. Thanks to this knowledge, together with the range velocity values deduced from different in situ measurements (ultrasonic and SLWTT tests), it was possible to implement and constrain the algebraic reconstruction technique (ART) by introducing prior knowledge of the investigated medium. From the analysis of the results of the SLWTT it was possible to locate damaged or altered zones inside the columns. These results were confirmed at a reliability level greater than 90 % by a few microcores on the most representative situations detected by SLWTT. Moreover, we applied a standard error analysis to evaluate accuracy in the computation of the velocity field. The computed standard deviation of mean velocities gives a relative error of 6 % of the computed mean velocity (about 2700 m/s). The RMS errors obtained by the previously described computation for the velocities relating to the altered and unaltered parts of the investigated structure give very small percentage errors (6 %), which validated the results of the SLWTT measurements.
Application of acoustic techniques in the evaluation of heterogeneous building materials
The accuracy of the reconstruction of the longitudinal seismic velocity distribution, anomaly localisation and resolution in the tomographic process can be improved by applying the proposed new experimental procedure based on the calculation of the cross-correlation function (CCF). The interpretation of the cross-correlograms relating to several ancient columns of the investigated historical Church of San Bartolomeo and deduced from the previously described processing sequence has been an objective constraint to precisely define the location and the geometry of anomaly zones of the transit times of the longitudinal wave rays. Thanks to this knowledge, together with the range velocity values deduced from different in situ measurements (ultrasonic and SLWTT tests), it was possible to implement and constrain the algebraic reconstruction technique (ART) by introducing prior knowledge of the investigated medium. From the analysis of the results of the SLWTT it was possible to locate damaged or altered zones inside the columns. These results were confirmed at a reliability level greater than 90 % by a few microcores on the most representative situations detected by SLWTT. Moreover, we applied a standard error analysis to evaluate accuracy in the computation of the velocity field. The computed standard deviation of mean velocities gives a relative error of 6 % of the computed mean velocity (about 2700 m/s). The RMS errors obtained by the previously described computation for the velocities relating to the altered and unaltered parts of the investigated structure give very small percentage errors (6 %), which validated the results of the SLWTT measurements.
Application of acoustic techniques in the evaluation of heterogeneous building materials
Anwendung akustischer Verfahren zur Bewertung heterogener Bauwerksmaterialien
Fais, S. (Autor:in) / Casula, G. (Autor:in)
NDT&E International ; 43 ; 62-69
2010
8 Seiten, 8 Bilder, 1 Tabelle, 18 Quellen
Aufsatz (Zeitschrift)
Englisch
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